Asian Marine Biology 10

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ASIAN MAR BIOLOGY 10

ASIAN MARINE BIOLOGY 10

ASIAN MARINE BIOLOGY 10 1993

The Marine Biological Association of Hong Kong

Hong Kong University Press *~*~~)!,[~

© Hong Kong University Press 1994 ISBN 962 209 356 6

Printed in Hong Kong by Nordica Printing Company Limited

THE MARINE BIOLOGICAL ASSOCIATION OF HONG KONG The Association was founded on 12 February 1982 with the following objects: (1) To encourage and assist marine biological research and its beneficial applications in Hong Kong.

(2) To provide means of communication among persons engaged in research in the marine sciences and to provide opportunity for them to forgather by the holding of meetings, symposia, conferences or other gatherings. (3) To act as spokesman when required, on behalf of the interests of marine biology in Hong Kong. (4) To co-operate with other scientific bodies and to seek such affiliations as may be appropriate. (5) To promote the understanding of marine biology in the field of education and amongst the general public in Hong Kong.

Membership of the Association is available in six classes: Full Members, Fellow Members, Student Members, Associate Members, Honorary Members and Sustaining Members.

(i) Full Members. Full members shall be persons who are or have been engaged in or directed research in a branch of marine science and who either possess appropriate academic qualifications or because of knowledge and experience occupy positions that ordinarily would, in the opinion of Council, require academic qualifications. (ii) Fellow Members. Fellow members shall be Full Members who in the opinion of Council are distinguished for their research in marine sciences in Hong Kong and will be entitled to use the designation FMBAHK. (iii) Student Members. Student members shall be persons who are studying relevant subjects at postsecondary but not postgraduate level. (iv) Associate Members. Associate members shall be persons who are interested in the objects of the Association, but do not qualify for full membership. (v) Honorary Members. Honorary members shall be persons distinguished for their research in marine science or who shall have rendered meritorious service to the Association. (vi) Sustaining Members. Sustaining members shall be persons, organizations or institutions who wish to support the objects of the Association.

Current annual subscription rates are set out on the application form available from: The Secretary, The Marine Biological Association of Hong Kong, c/o The Swire Marine Laboratory, The University of Hong Kong, Cape d' Aguilar, Hong Kong

THE MARINE BIOLOGICAL ASSOCIATION OF HONG KONG Officers and Council Honorary President

: Dr L.H.Y. Lee, Ph.D., 1.P.

Honorary Vice-Presidents

: Prof. Wang Gungwu, C.B.E., M.A., Ph.D., F.A.H.A. : Prof. R.S.S. Wu, Ph.D.

Council Chairman

: Prof. Brian Morton

Vice-Chairman

: Dr S.T. Chiu

Secretary

: Dr P.M.S. Mak

Treasurer

: Dr R.Y.H. Cheung

Meeting's Secretary

: Dr S.F. Leung

Membership Secretary

: Dr S.Y. Lee

Librarian

: Dr 1.1. Hodgkiss

Members

: Dr K.H. Chiu : Dr R.G. Ong Che : Dr G. Hodgson

Registered address

: clo The Swire Marine Laboratory, The University of Hong Kong, Cape d' Aguilar, Hong Kong

ASIAN MARINE BIOLOGY Editor Prof. Brian Morton, Department of Zoology and The Swire Marine Laboratory, The University of Hong Kong, Hong Kong Business Editor Dr R. Y .H. Cheung, Department of Biology and Chemistry, City Polytechnic of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Editorial Board Prof. C. Birkeland, University of Guam Marine Laboratory, UOG Station, Mangilao, Guam 96913, USA Dr Y.H. Chien, Department of Aquaculture, National Taiwan College of Marine Science and Technology, Keelung, Taiwan Dr T.E. Chua, International Center for Living Aquatic Resources Management (lCLARM), MC PO Box 1501, Makati, Metro Manila, Philippines Dr L.G. Eldredge Pacific Science Association, PO Box 17801, Honolulu, HI 96817, USA Dr Y.B. Go, Department of Oceanography, College of Ocean Science and Technology, Cheju National University, Cheju 590, South Korea Prof. E.D. Gomez, Marine Sciences Center, University of the Philippines, Diliman, Quezon City 3004, Philippines Dr T.J. Lam, Department of Zoology, National University of Singapore, Kent Ridge, Singapore 0511 Dr S.D. Maynard, Marine Option Program, University of Hawaii, Marine Sciences Building, 1000 Pope Road, Honolulu, HI 96822, USA Dr P. Menasveta, Department of Marine Science, Chulalongkorn University, Phya Thai Road, Bangkok 5, Thailand Prof. T. Okutani, Tokyo University of Fisheries, 4-5-7, Konan, Minato-ku, Tokyo 108, Japan. Prof. C.K. Tseng, Institute of Oceanography, Academia Sinica, 7 Nan-Hai Road, Qingdao, People's Republic of China Dr M. Williams, Australian Institute of Marine Science, P.M.B. No. 3, Townsville MC, Queensland 4810, Australia Dr Yu. M. Yakovlev, Institute of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690032, Russia

INSTRUCTIONS TO AUTHORS

1.

Submission of manuscripts. Papers should be sent to: The Editor, Asian Marine Biology, The Swire Marine Laboratory, The University of Hong Kong, Hong Kong. The submission of a manuscript will be taken to imply that the material is original and that no similar paper is being, or will be, submitted for publication elsewhere. When accepted, the copyright of a paper becomes the property of The Marine Biological Association of Hong Kong and permission must be obtained to reproduce material from papers published by the Association. Theses and serialized studies should not be submitted.

2.

Manuscripts. Papers should be written in clear, concise English with the minimum number of tables and illustrations. Form and content should be carefully checked before submission to avoid the need for corrections in proof. A charge will be made for changes introduced after an article has been typeset. The text may be arranged as follows: (a) Title. This should be concise, specific and typed on a separate cover sheet together with the name(s) of the author(s) and that of the institution in which the research was carried out. The name of a new genus or species must not be included in the title. A short title, of not more than 40 characters (including spaces), should be provided for page headings. (b) Abstract. This should generally not exceed 200 words and must be intelligible to the reader without reference to the main text. Avoid abbreviations. (c) Introduction, followed by the subject matter of the paper. (d) Materials and methods. (e) Results. (f) Discussion (g) Acknowledgements. (h) References-See Section 6. (i) Illustrations-See Section 4. If the paper is short, it may be preferable not to divide it into sections.

3.

Presentation. Two copies of the typescript should be provided, double spaced throughout (including tables, legends and footnotes) on one side of quarto or A4 paper, with a margin of 2.5 cm all round. Please indicate the position of tables and illustrations in the text; tables and legends for illustrations should be typed separately at the end of the manuscript. All pages should be numbered serially and fastened together securely. Except for short contributions, papers should be divided into sections described by headings. The first subhead will be shouldered, the second italicized shouldered and the third run-on with the copy. An initial capital letter must be used for proper names, the Latin names of orders, families and similar names, but not for anglicized derivatives from Latin names or for English names of plants and animals. Generic and specific names must be underlined. Footnotes should be avoided but if essential, must be indicated by superscript figures in the text and collected on a single page placed at the end of the manuscript. If it is necessary to refer to various passages in the text, please ensure that the relevant manuscript page number is given.

Instructions to Authors

If a new taxon is described, the institution in which the type material is deposited must be indicated together with details of the registration assigned to it. Customary abbreviations will be used. Citations in the text should read (Brown 1975) or Brown and Jones (1975). When a paper has more than two authors, the style Smith et al. (1980) or (Smith et al. 1980) should be used. The convention (Brown 1975a), Brown (l975b) should be used when more than one paper is cited by the same author(s) and published in the same year. Note that these papers should be alphabetized by title, discounting an initial article.

4.

Illustrations. All illustrations will be reduced to a size not exceeding 19 x 14 cm. No illustrations should be submitted which will not fit into an envelope 35 x 47 cm. A metric scale should preferably be included on each illustration. If this is not possible, the magnification (or reduction) should be given in the legend and adjusted after any modification in the size of the illustration. Line drawings are referred to as Fig. 1, Fig. 2, etc., and halftone blocks as Plate I, Plate 2, etc. If a line drawing or halftone plate is composed of more than one SUbject, one should be identified as (A), (B), etc. The name(s) of the author(s) and the number of the figure or plate must be marked on the back of all illustrations, and the orientation of the illustrations indicated. (a) Line drawings. These should be submitted on quarto (28 x 21.5 cm) or A4 (30 x 21 cm) sheets. Drawings should be in Indian ink on tracing linens, Bristol board or faintly blue-lined graph paper. Photocopies of drawings cannot be reproduced satisfactorily, but may in the first instance be submitted, and the original drawing sent if the paper is accepted. Explanations should, as far as possible, be placed in the legend; any necessary lettering on figures should be lightly inserted in blue pencil. Graph curves may be distinguished by use of solid pecked --- or dotted ... lines. The following symbols available to the printer also, can be used for experimentally determined points and for keying in the legends: 0, e, 0, ., ~, . , V, ~. (b) Photographic halftone illustrations. Best quality glossy prints should be submitted of a size capable of reduction rather than enlargement. Photographs should be mounted on white backing board and grouped as they will be reproduced.

5.

Numerical matter. Metric system to be used throughout. Only the minimum of numerical matter essential for clarity should be included.

6.

References. Important: Authors are requested to check the list of references against the text to ensure that: (a) The spelling of authors' names and the dates given are consistent. (b) All authors quoted in the text are included in the list of references. If more than one reference by the same author(s), published in the same year is cited, use, a, b, etc., after the year in both text and list, e.g., 1963a. Text citations can be given in either of two ways: (i) Single author: Where more than one reference is given for a single author the publications should be listed chronologically. (ii) Two authors: References for which there are two authors should be arranged first alphabetically then chronologically. For text citations, use both authors' names and the year. Do not use et al. for two author references. (iii) Three or more authors: References with three or more authors should be arranged first alphabetically then chronologically. For all citations in the text it is usually sufficient to quote the surname of the first author, followed by et al. and the date, but for reasons of clarity it may sometimes be necessary to use the names of the first two (or more) authors. ix

Instructions to Authors

Please note that the names of all authors should be given in the list of references and et al. used only in the text. The full title of the paper must be given. Journal titles must also be given in full. The volume number should be followed by the first and last pages of the paper. Include the issue number only when the journal referred to is paginated by issue rather than by volume.

Examples Journal references: Beklemishev, K. V. 1952. Nutrition of predatory intertidal invertebrates and their feeding interrelations with commercial fish and birds. Trudy Vsesoyusnogo Hidrobiologicheskogo Obschestva 5:276-96 (in Russian). Ponder, W.F., Colman, P.H., Yonge, C.M. and Colman, M.H. 1981. The taxonomic position of Hemidonax Morch, 1871 with a review of the genus (Bivalvia: Cardiacea). Journal of the Malacological Society of Australia 3:41-64. Shapiro, D. Y. 1981. Size, maturation and the social control of sex reversal in the coral reef fish Anthias squamipinnis. Journal of Zoology, London 193: 105-28. Tyler, P.A. and Gage, J.D. 1982. The reproductive biology of Ophiacantha bidentata (Echinodermata: Ophiuroidea) from the Rockall Trough. Journal of the Marine Biological Association of the United Kingdom 62:45-56. Book references: Huang, Z.G. and Cai, R.X. 1984. Marine Biofouling and Its Prevention. Beijing: China Ocean Press. (In Chinese) Johnson, R.W. and Ohlhorst, C.W. 1981. Application of remote sensing to monitoring and studying dispersion in ocean dumping. In Ocean Dumping of Industrial Wastes (ed. B.H. Ketchum, D.R. Kester and P. Kilho Park). Vol. 12, Marine science, 175-9l. New York and London: Plenum Press. (Note: 'ed.' here means 'edited by', hence never 'eds.') King, C.A.M. 1972. Beaches and Coasts. London: Edward Arnold. Lam, C.W.Y. 1979. The Assessment of Eutrophication in Estuaries: A Review of New Zealand and Overseas Studies. Hamilton Science Centre Internal Report No. 79/38. 44 pp. New Zealand: Ministry of Works and Development. Morton, B. and Tseng C.K., eds. 1982. The Marine Flora and Fauna of Hong Kong and Southern China. 2 vols. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. (Note: 'eds.' here means 'editors') Tsi, C.Y. and Ma, S.T. 1982. A preliminary checklist of the marine Gastropoda and Bivalvia (Mollusca) of Hong Kong and southern China. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 431-58. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Unpublished material: Cortes-Zaragoza, E. 1983. Morphometrics and relative abundance of tunas (Perciformes: Scombridae) caught off Darigayos Cove, La Union. 85 pp. M.Sc. thesis, University of the Philippines. Shin, P.K.S. 1986. Effects of a spill of bunker oil on the marine biological communities in Hong Kong. Paper presented in the International Symposium on Environmental Pollution and Toxicology, 9-11 September 1986, Baptist College, Hong Kong. x

Instructions to Authors

7.

Proofs. One set of galley proofs and the original manuscript will be sent to the author. Corrections should be made on the marked copy which should be returned with the original manuscript to: The Editor, Asian Marine Biology, The Swire Marine Laboratory, The University of Hong Kong, Hong Kong. Page proofs will not normally be sent to the author.

8.

Copyright/Offprints. Authors submitting a manuscript do so on the understanding that if it is accepted for publication, copyright shall be assigned to The Marine Biological Association of Hong Kong. Offprints may be ordered at the proof stage. The Association will not put any limitation on the personal freedom of the author to use material contained in the paper in other works which may be published elsewhere.

9.

Important. Whenever a Latin name is employed it must be followed by the authority, e.g., Anomalocardia squamosa Lamarck, on first usage in the paper. Authors are reminded that: (a) Descriptions of new taxa must follow the Rules and Recommendations of the International Commission on Zoological (or Botanical) Nomenclature. (b) All primary types of new taxa must be quoted in the paper. (c) Vouchers specimens of each taxon discussed should be deposited in a recognized institutional collection and a registration number obtained which should be quoted in the paper.

10. Word-processor disks. All manuscripts must be provided on a floppy disk after the paper has been accepted for publication, in addition to the final printed version. It will speed the publication of your paper if you can send a copy of the text on 360K or 1.2M 5.25" disk for IBM personal computer, or compatible, or 720K or 1.44M 3.5" disk for Apple Macintosh computer. The disk will be returned to you. (a) Ensure that the disk you send contains only the final version of the paper and is identical to the typescript. (b) Label the disk with author's name, title of paper, machine and the word-processing programme used. (c) Supply the file as a fully formatted 'text only', WordS tar (4 or above) or WordPerfect (4 or above) file on IBM personal computer or a Microsoft Word (3 or above) file on Apple Macintosh computer. (d) Use no special formatting characters. (e) Comply as closely as possible with the general Instructions to Authors.

xi

EDITORIAL From 9-11 September 1992, The Marine Biological Association of Hong Kong and the Agriculture and Fisheries Department and the Environmental Protection Department of the Hong Kong Government coorganized a Colloquium on Red Tides in Hong Kong and South China, attended by some thirty scientists from Hong Kong, China and Great Britain. A total of 14 papers were presented, some of which are, following peer review, published in this issue of Asian Marine Biology. The growing problem of red tides in the coastal waters of the South China Sea is now attracting a greater level of concern. The Second International Conference on the Marine Biology of the South China Sea was convened in Guangzhou from 3-7 April 1993. Organized by the Marine Biology Research Station at Dayawan of The South China Sea Institute of Oceanology, Chinese Academy of Sciences, and the Guangdong Society of Oceanology and Limnology, in conjunction with The Marine Biological Association of Hong Kong, the Conference was a great success. Its success was slightly marred by the fact that very few delegates from countries other than China and Hong Kong could attend. Notwithstanding, there were some ninety delegates, with Hong Kong represented by 23 members of the Association, both scientists and students. The few other delegates were from the United Kingdom (2), the United States (1) and Taiwan (1). The real achievement of the Conference, however, was its organization, being convened in an international hotel and with all talks being in English and, in general, well-presented. The range of talks was extremely wide but I do not consider this to be a particular problem, it probably being more appropriate for such a meeting that delegates obtain a broader insight into the marine biology of the South China Sea. One day, specialist meetings on the South China Sea may be convened, as with the Red Tide Colloquium, but it seems sensible that the triannual meeting be broad-based. The next Conference will be held in Hong Kong in 1996. The Proceedings of the 1993 Conference will be published, after the selected papers have been refereed, by Ocean Press, Beijing. Artificial Reefs have been built in the sea in the United States and Japan and an experimental one made from pulverized fuel ash (PFA) was established by The University of Southampton, UK, three years ago. Now Hong Kong is to have its first such structure and made, like the Southampton model, from experimental PFA/cement mixes. Hong Kong is losing its natural shoreline and shallow subtidal marine habitats fast as a consequence of coastal reclamation. The pace of such reclamation has been stepped up in recent years, particularly with regard to the Port and Airport Strategy (PADS) and the development of the new airport at Chek Lap Kok and the associated reclamation of West Kowloon and North Lantau. Completion of this project will mean that some 18% of Hong Kong's shoreline has been reclaimed. The consequences of such developments and of the sand dredging that is needed to complete them are that Hong Kong will have lost coastal zone areas which are the habitat of mangroves, sea grasses and corals, which are, in turn, the most delicate of our marine communities. Nursery areas for fish and prawns will also be lost. The aims of the Artificial Reef project are, therefore, to ascertain whether such structures can replace reclaimed habitat, particularly for corals, and whether or not they do act as either fish aggregating or fish breeding devices. It is, however, also important to know whether the potentially toxic trace metals found in the PFA are either leached out during immersion or are sealed into the fabric of the reef by the cement, the encrusting organisms and by the hardening effects of seawater. If the experiment works and it can be proven that trace metals are not released from the blocks, it is possible that Artificial Reefs of PFA may become a feature of Hong Kong's coastal wa"ters. Two fatal shark attacks occurred in Hong Kong's eastern waters in early June 1993. Recent fatal shark attacks were in 1979 and 1991 although it is possible that the occasional 'disappearance' of

Editorial

swimmers is also attributable to such attacks. The culprit(s) in 1993 seem to have been tiger sharks that moved into Hong Kong's waters in early summer. The same is possibly true of the 1979 and 1991 cases since these occurred in August and June, respectively. The Hong Kong government seems to have been at quite a loss to know what to do, in terms of public safety at swimming beaches, about such attacks, but one local newspaper sponsored the employment of a shark 'expert' or 'hunter' to kill what he believed to be a rogue shark, malevolently stalking human beings. This has possibly sold newspapers but it also created a local feeling of paranoia reminiscent of the movie 'Jaws' and drowned any scientific debate on possible means to manage at least some local beaches so that they are shark-free. Hong Kong does not have any shark researchers and, in their absence, calls for sensible experts to be brought in from overseas, namely Australia, have been ignored and attention focused instead on the hunter. I believe such hunting is futile since one can never be sure of the true identity of the attacker, nor if there is only one 'rogue' (which I do not believe in anyway). To make Hong Kong's shores safe from shark attack, we would have to kill all of them in the South China Sea. It is almost certainly true that such attacks are 'accidents' waiting to happen, the swimmer being in the wrong place at the wrong time, that is Hong Kong's eastern waters and early in the morning. The analogy is with the chance of being hit by lightning. This, I know, is of no solace to the grieving families of the victims but the truth of the matter is that in sub-tropical Hong Kong, probably anywhere, one has to realize that when you enter the sea you are entering the habitat of a significant predator. Whatever we do in life involves us making decisions about the risks involved. Ultimately the responsibility for swimming in shallow, sub-tropical, seas is our own but, notwithstanding, it does seem incumbent upon the government to try and ensure that at least some of the most popular beaches are shark-free, if only during the summer when many people enjoy swimming. At the 11 th Annual General Meeting of The Marine Biological Association of Hong Kong, the following were either elected or re-elected to office: Dr. S.T. Chiu (Vice-Chairman), Dr P.M.S. Mak (Secretary), Dr R.Y.H. Cheung (Treasurer), Dr. S.Y. Lee (Membership Secretary), Dr R.G. Ong Che (Councillor) and Dr K.H. Chiu (Councillor). Stepping down as Vice-Chairman of the Association is Dr N.Y.S. Woo who has served in this capacity since 1990. Grateful thanks are extended to Dr Woo for his service to the Association. Welcomed onto the Editorial Board of Asian Marine Biology is Dr M. Williams who has replaced Dr J.T. Baker upon his retirement as Director of the Australian Institute of Marine Science and Dr L.G. Eldredge, Executive Secretary of the Pacific Science Association, Hawaii.

Brian Morton

xiv

CONTENTS

The Marine Biological Association of Hong Kong ................................................................................

v

Asian Marine Biology-Editorial Board .................................................................................................. vii Instructions to Authors ............................................................................................................................... viii Editorial ........................................................................................................................................................ xiii Fouling polychaetes of Hong Kong and adjacent waters Wang Iianjun and Huang Zongguo .................................................................................................... . Four new species of Cumacea from Peter the Great Bay, Sea of Japan Ludmilla A. Tzareva and Stella V. Vassilenko ...................................................................................

13

The effects of physical factors and grazing by limpets on the colonization, growth and composition of intertidal algae on a rocky shore at Cape d' Aguilar, Hong Kong I.H. Liu ................................................................................................................................................... 27 Biosynthetic conditions and properties of Streptomyces sp. chitinase isolated from the mangrove rhizosphere Zheng Zhicheng, Zhou Meiying and Zheng Tianling ........................................................................

41

Marine enclosure ecosystem experiments to study red tide mechanisms and processes in Xiamen Harbour, China Lin Yu, Zhuang Dongja, Tang Senming and Chen Xiaolin ..............................................................

45

Some coral reef pontoniine shrimps from Vietnam A.I. Bruce ...............................................................................................................................................

55

Assessing the limiting factors of red tide by bottle bioassay K. C. Ho and /,1. Hodgkiss ...... .................................................................................................... 77 Effect of experimental harvesting on kelp regrowth and on the structure of the shallow-water communities of Bering Island (Commander Islands) V. V. Oshurkov and E.A. Ivanjushina................................................ ................................................... 95 Barnacles as biomonitors of trace metals in the coastal waters near Xiamen, China P.S. Rainbow, Huang Zongguo, Yan Songkai and Brian D. Smith ................................................. 109 Larval development of Eupentacta fraudatrix (Holothuroidea: Dendrochirota) Igor Yu. Dolmatov and V. V. Yushin .................................................................................................... 123

Asian Marine Biology 10 (1 993): 1-12

FOULING POL YCHAETES OF HONG KONG AND ADJACENT WATERS Wang Jianjun and Huang Zongguo Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China

Abstract From 1980 to 1989, 372 samples of fouling organisms were collected from ships, piers, buoys and mariculture cages in Hong Kong and adjacent waters. Seventy species of polychaetes have been recorded. Hydroides elegans, H. dirampha, H. inornata and Pomatoleios kraussii were the dominant species. These are also major biofoulers in Hong Kong, the maximum recorded wet weight of these organisms being 20.34 kg·m- 2 • The distributions of the species in relation to tidal level, salinity gradient and degree of tidal exposure were studied and corresponding indicator species for these different environmental conditions identified.

Introduction There have been few studies of Hong Kong's polychaete fauna. Mak (1980) and Shin (1982) identified species from corals and subtidal sediment habitats, respectively. Hutchings (1990) investigated Hong Kong's Terebellidae and Mackie (1990) the Poecilochaetidae and Trochochaetidae. Mackie and Hartley (1990) described a new species of Prionospio from Hong Kong and Mackie (1991) a new species of Scoloplos. Ohwada (1992) has also described a new local species of Aglaophamus. Although there have been a number of studies of Hong Kong's marine fouling community (Vrijmoed 1973; Greene and Morton 1976; Vrijmoed et al. 1986; Huang and Mak 1982; Huang et al. 1992), there is little known about fouling polychaetes in particular and some of which, e.g., Hydroides elegans (Mak and Huang 1982), are significant. This paper focuses attention on Hong Kong's fouling polychaetes.

Materials and methods From 1980 to 1989, 372 samples of fouling organisms were collected from 64 sites in Hong

Kong and adjacent waters (Fig. 1), including the high, middle and lower tidal levels of the pilings of 29 piers; the water lines, sides and hulls of 22 ships; the water lines, sides, anchor chains and anchoring blocks of 17 buoys; and the cages and rafts at 10 mariculture zones. Such stations are spread all over the estuarine, transitional and marine zones of Hong Kong's waters, as proposed by Morton (1982). Additional samples were collected from the Pearl River estuary. The polychaete communities were analysed, to identify the species, their significance as foulers and their relationship to salinity, tidal level and degree of tidal exposure.

Results Species Seventy species of fouling polychaetes were recorded from the 372 samples obtained during this study, belonging to sixteen families. There were twenty tubiculous and sedentary species, including ten species of Sabellidae and Terebellidae living in membranous tubes and 10 species of Serpulidae and Spirorbidae in calcareous tubes (Table 1). Twelve species were not identified.

J.J. Wang & Z.G. Huang

JULY

30'

20'

A test panels

22" 10'

•

fixed piers

.;.

buoys

-c:: cages and rafts

b

vessels

4 4

,

ESTU~RINE

0

~

a

TRANSITIONAL OCEANIC '----------------------------~~----------------

Fig. 1. A map of Hong Kong and adjacent waters showing the sampling sites and; above; salinity profiles for the Pearl River in January and July. 1. Hunan buoys, 2; Shajiao buoys, 3; Shajiao pier, 4-19; Lingding buoys, 20-21; Chiwan buoys, 22; Shekou pier, 23-27; Deep Bay buoys, 28; Tsim Bei Tsui pier, 29; Lau Fau Shan pier, 30; Tap Shek Kok pier, 31; Tai Lam Chung pier, 32; Tsing Yi pier, 33; Tung Chung pier, 34; Tung Chung cages, 35; Tai 0 pier, 36; Cheung Chau pier, 37; Hong Kong boats and ships, 38; Kennedy Town pier, 39; Tsim Sha Tsui pier, 40; Central District pier, 41; North Point pier, 41; North Point pier, 42; A Kung Ngam pier, 43; Tai Tam pier, 44; Tai Tam buoys, 45; Tai Tam panels, 45a; Cape d'Aguilar rocks, 46; Aberdeen pier, 47; Picnic Bay cages, 48; Shipwreck buoys, 49; Pak Sha Wan cages, 49a; Sai Kung pier, 50; Tap Mun pier, 50a; Tap Mun cages, 51; Wong Shek pier, 52; Wu Kai Sha pier, 53; Chinese University pier, 54; Sam Mum Jai pier, 55; Tai Mei Tuk cages, 56; Tolo Harbour buoys, 57. Lo Fu Fut cages, 58; Kat 0 cages, 59; Kat 0 pier, 60; Kat 0 panels, 61; Obei Tang cages, 62; Ping Chau pier, 63; Nanao pier, 64; Yantian pier.

2

Table 1. Fouling polychaetes recorded from Hong Kong and adjacent waters. Species

Occurrence times

Numbers

Tidal levels

Salinity tolerances

Sites

Cirriformia capensis

3

111

M-S

h

51,64

C. tentaculata

5

33

L

e

39-42

2

L

h

63

L

e

38

70

H-S

h, e

2

S

e

6

H-L

h, e

CIRRATULlDAE

OPHELLlDAE Polyophthalmus pictus PHYLLODOCIDAE Eumida sanguinea Eulalia viridis

21

Phyllodoce sp. Genetyllis castanea

3

16, 18, 20-21, 32, 37-42, 49, 51-52 55 41-42, 49a

HESIONIDAE Micropodarke dubia

H

53

SYLLlDAE Myrianida cf. pachycera

32

Syllis amica

49a

3

"Tl

0

c

3" co "0

0

-<

S. gracilis

11

37

H-S

h, e

Trypanosyllis zebra

4

10

H-S

e

32, 38, 44

CD en

T. taeniaformis

2

7

M-L

e

41, 51

I

2

L

62

co

20,31,44,48, 49a, 50, 51

(")

;;sO> Cl)

S0

::J

Typosyl/is varegata

"

0

W

::J

co

~

c....

Table 1 (continued)

Species

i:....

Occurrence times

Numbers

Tidal levels

T. fasciata

5

131

S

Typosyl/is sp.

7

32

M-S

Salinity tolerances

Sites

::1E

Ql ::l

co

Qo

h

(;)

49a, 51-52, 59

c

71

1242

Halosydna sp.

H-S

h, e

14-27,31-32,36-44,48, 49a, 50-51, 58, 62-64 40

L

Nonparahalosydna pleiolepis

15

293

L-S

e

18-21,32,37-38,41,44

Lepidonotus cf. dentatus

2

2

S

e

37, 44

L. squamatus

4

6

M-S

e

38, 42-43

L. tenuisetosus

7

26

H-M

h, e

31,36,49a,51-52

NEREIDIDAE 24

14

Leonnates decipiens Ceratonereis hircinicola

:::r:

Ql ::l

co

POLYNOIDAE Halosydna brevisetosa

N

20

2

C. marmorata

7

S

21,23

2

L

32

Platynereis bicanaliculata

4

9

S

e

21,23,48

Ne re is multignatha

33

443

M-S

h, e

13-27,31-32,37-41,44,58,63-64

N. nichol/si

12

90

M-S

H, E

18,37-38,42,44,48,50

N. neoneanthes

6

41

L-S

h, e

16, 24-27, 37, 58, 64

N. pelagica

7

18

H-S

e

N. persica

12

117

S

Neanthes succinea

14

138

M-S

37-41,44 9, 16-25

e

21,32,37,40-41,55

Table 1 (continued) Species

Occurrence times

Numbers

Tidal levels

Salinity tolerances

N. ct. virens

Sites 37

Nectoneanthes multignatha

12

L

52

7

74

S

12-16, 20, 23-26

61

631

H-S

5

S

39

269

H

t, 1

3

6

H-M

e

32, 43

2

M

h

63

2

19

H-M

h

63

Eunice antennata

2

6

L-S

e

43-44

Lysidice ninetta

11

59

M-S

e

24-25, 41-44,47, 50, 55, 59,63-64

Marphysa sanguinea

15

53

M-S

e

14,16,21,32,37,39,41,48,63

Pa/o/a siciliensis

2

6

M-L

e

39, 42-43, 47

N.oxypoda Perinereis cu/trifera P. camiguinea P. nuntia P. vancaurica Pseudonereis anoma/a P. variiegata

e

15, 18,21-25,31-32,36-44,47-52,62-64 24-25 5-9, 12-15, 20-25, 36-44, 47-52, 62-64

EUNICIDAE

LUMBRINERIDAE

Lumbrineris sp.

=-5" <0 "0 0

4

8

M-L

e

39

-< 0 ::::T

Q) (l)

ARABELLlDAE

Arabella iric%r

"'Tl 0

CD en

4

M

h

45a

0

::I:

0

:::l

<0

A

0

01

:::l

<0

(J)

(....

Table 1 (continued) Species

L

Occurrence times

Numbers

Tidal levels

Salinity tolerances

Sites

:E

III ~

co Ra N

DORVILlEIDAE

Cv ::r:

Dorvillea cf.

c

III ~

pesudorubrovittata

3

16

L

f, e

3, 32, 39, 41

Dorvillea sp.

3

22

S

f, e

1-2, 23

2

2

M

e

39, 63

Demonax japonicus

8

30

L-S

e

37-38, 43-44

D. microphthalmus

44

816

M-S

e

20-23, 32, 37-44, 47, 49, 51-53

Sabel/a albicans

3

38

S

e

37

Potamilla torelli

3

83

M-S

e

37, 39, 44

4

L

e

38

FLABELLlGERIDAE Pherusa parmata SABELLlDAE

Pseudopotamilla cf. veniformis Hypsicomus sp.

2

4

L

e

40, 42

Branchiomma cingulata

2

4

L-S

h, e

37, 59

8

45

L-S

e

3

S

TEREBELLlDAE Loimia medusa Terebel/a punctata

20-23, 39, 44, 64 44

co

Table 1 (continued) Species

Occurrence times

Numbers

Tidal levels

Salinity tolerances

13

6443

L-S

e

Sites

SERPULlDAE

Serpu/a vermicu/aris Serpu/a watsoni

32, 37, 39, 44

L

38 15,20-21

7

56

L

H. dirampha

33

1705

M-S

e

20-21,32,37-42,47-48

H. e/egans

120

9000

M-S

e

32, 37-44, 50-59, 62, 64

S

e

37

Hydroides a/biceps

H. ct. ezoensis H. inornata

14

1636

M-S

e

36-41

Pomato/eios kraussii

32

9000

H-S

e

21,24,31,36-44,47,49,50a

6

10

L-L

e

22, 47, 59, 63

Oexiospira foraminosus

4

197

M-L

h

49, 51-52, 59

Spirorbis sp.

5

570

M-L

h

49a, 62-63

Spirobranchus tricornis SPIRORBIDAE

"

o

H, M, Land S are high, middle and low tidal levels and the sublittoral zone. h, I, e and water, respectively,

t are

high salinity, low salinity, euryhaline and fresh

S3' co "'0

o

-< o ~

Ql

CD

CD C/l

sa. ::I:

o

::J

co -..J

=" o ::J co

J.J. Wang & Z.G. Huang

Distribution Horizontal distribution Table 1 lists the sampling sites from which every species was obtained. The distribution characteristics of the species appear to be closely related to salinity and degree of tidal exposure.

Salinity Most of the polychaete species identified are euryhaline and are distributed from the low salinity areas of the Pearl River estuary in the west of Hong Kong to the high salinity waters of Mirs Bay in the east. There were more species either in or near high salinity areas than low salinity areas of the Pearl River estuary. Typical high salinity tolerant species were Arabella iricolor, Dexiospira foraminosus and Cirriformia capensis. Low salinity tolerant species were Nereis persica, Nectoneanthes oxypoda, Hydroides albiceps, Perinereis nuntia and Dorvillea spp., some of which were found at sites 1 and 2 near the freshwater and middle reaches of the Pearl River.

Degree of tidal exposure Most of the species were distributed in sheltered and slow-moving waters. Many errant (freeswimming) polychaetes lived in the crevices of large fouling organisms, such as barnacles and oysters. A typical example was the small syllid, Syllis gracilis. Some species that were collected from buoys at sites 13-19 and 48 can withstand a high degree of tidal action in open waters. For example, Arabella iricolor was only collected from wave-exposed rock faces at Hezuijiao. This species is adapted to strong wave action and an oceanic environment.

Vertical distribution Most of the species were distributed in the low tidal and sublittoral zones. Some species were, however, collected from high tidal levels, e.g., Perinereis nuntia. Micropodarke dubia and Syllis amica were also collected from higher tidal levels. These species usually occurred in the crevices of oysters and barnacles. 8

Biofouling significance Eighteen species were collected more than ten times in the 372 samples. The occurrence records for Hydroides elegans, Halosydna brevisetosa and Demonax microphthalmus were between 40-120 times. The individual numbers recorded for seventeen species were all greater than 100·m-2 • In particular, the numbers of H. elegans, H. dirampha, H. inornata, Serpula vermicularis, Pomatoleios kraussii and Halosydna brevisetosa were greater than 1000 individuals·m- 2 (Table 1). Some species of Serpulidae occurred in great numbers in Hong Kong waters, and are the major fouling organisms of mariculture rafts, ships and wharf pilings. Many species of Serpulidae had a peak period of reproduction from April to May, e.g., Hydroides elegans, H. inornata, H. dirampha and Serpula vermicularis. Juveniles of these species colonized the substratum in large numbers and grew quickly on newly submerged mariculture cage nets. The nets of cages were completely colonized by these organisms after immersion for one month, each net knot being covered by -15 individuals. The net holes of mariculture cages submerged for seven months in Baisha Bay were blocked by H. elegans, the thickness and wet weight being 38 mm and 12.48 kg·m- 2 , respectively (Table 2). On pontoons and tugboats which were in the water for a long period of time, the hulls were often covered by Hydroides elegans. Their densities were often so large (3.3 x 10 5 individuals·m- 2) that the white, calcareous tubes grew upwards, the maximal wet weight being 12.22 kg·m- 2 • On ferry docks and lines, the wet weight of H. elegans on some unpainted areas reached 20.48 kg·m- 2 • On the newly-built pilings of the wharf at The Marine Science Laboratory of The Chinese University of Hong Kong, the area below low tide was covered by Hydroides elegans after five months, the thickness and wet weight being 30 mm and 16.71 kg·m- 2 , respectively (Table 2). Meiwo Wharf was built several years ago. The piles corresponding to middle and low tidal levels were covered by Pomatoleios kraussii, the density being as high as 3.0 x 105 individuals·m- 2 , the tubes growing vertically, and the thickness and

Table 2. The characteristics of Hydroides elegans and other tubiculous polychaetes recorded from some structures in Hong Kong waters. Period of immersion (months) Ships

Culture cages

Low tidal levels of piers

Wet weight (kg·m-2 )

Thickness (mm)

Area of cover (%)

Density (individuals·m-2 )

Tugboat

12

12.22

30

70

330,000

Pontoon

16

4.83

15

100

-

Ferry

6

6.68

28

100

-

Liner

12

20.34

16

100

-

Pak Sha Wan

7

12.48

38

100

-

Tap Mun

3

1.65

4

-

-

Lo Fu Fut

3

1.54

13

-

-

Tsing Yi

36

1.57

-

-

-

North Point

36

2.32

15

-

"Tl

o

The Chinese University of Hong Kong

5

16.71

30

£. 5'

-

100

co

"0

o

---

-

----_._-

-

-

- -

-< o

:::r

III

Cl)

CD en

sa. I

o

::J

co

~

o CD

::J

co

J.J. Wang & Z.G. Huang

Table 3. The characteristics of Pomato/eios kraussii on the pilings of two piers in Hong Kong waters. /

Wet weight (kg·m-2 )

Density (individuals·m-2 )

0.78

11,250

-

-

High

0.89

66,666

-

-

Middle

5.56

299,997

100

16

Low

4.51

222,220

100

-

Tai Tarn

Kat 0

wet weight being 16. mm and 5.56 kg·m- 2 , respectively. The surface of the oyster shells collected from high and middle tidal levels at Tai Tarn Pier were also covered by P. kraussii (Table 3).

Discussion Mak (1982) and Shin (1982) report on the marine polychaetes of Hong Kong. During this study, more species of polychaetes were recorded because of the greater extent of the survey area than that investigated by these authors. Some polychaete species that are typical of biofouling communities (lmajima 1980) were also found. Numerous workers have noted that ships can carry fouling organisms into waters in which such species are not reported to occur (Arakawa 1980; Huang and Cai 1984; Morton 1987). Hydroides elegans and Ficopomatus enigmaticus are believed to be introduced into Japan (Arakawa 1980). These species reproduce massively and seriously affect the output of cultivated oysters in Japan. F. enigmaticus was not recorded from this survey, but small numbers of Hydroides ezoensis were collected. The latter species is a major fouling organism along the coast of northern China (Liao 1981; Huang and Cai 1984; Yang and Sun 1988).

10

Area of cover (%) Thickness (mm)

Its appearance in Hong Kong may be related to carriage by ships from these waters. In the development of biofouling communities, tubiculous polychaetes are often dominant only in the initial stage of community formation. Climax biofouling communities are usually dominated by large and long-lived species such as oysters, sponges and barnacles. On some wharfs, ships and mariculture cages in Hong Kong, however, either Hydroides elegans or Pomatoleios kraussii are still dominant in the climax community, indicating the local importance of these species. It also suggests that these species can outcompete other biofouling organisms. This study thus demonstrates that small species can exclude other large species and become dominant in the community structure by virtue of high population densities, centralized settlement periods and rapid growth rates. Acknowledgements Dr P.M.S. Mak, Fisheries Research Station of the Department of Agriculture and Fisheries of the Hong Kong Government, participated in part of this study. Staff of the Biofouling Research Group of the Third Institute of Oceanography also took part in sampling from the Pearl River estuary. We extend our gratitude to them.

Fouling polychaetes of Hong Kong

References

Arakawa, K. Y. 1980. On alien immigration of marine sessile invertebrates into Japanese waters. Marine Fouling 2:29-33. Oreene, O.W. and Morton, B. 1976. Preliminary fouling and corrosion studies of painted metals in Hong Kong harbour. In Proceedings of the IV International Congress on Marine Corrosion and Fouling, Juan-Ies-Pins, Antibes, France, 1976, 225-36. Huang, Z.O. and Cai, R.X. 1984. Marine Biofouling and its Prevention. Beijing: China Ocean Press. Huang, Z.O. and Mak, P.M.S. 1980. The salinity tolerance of the serpulid polychaete, Hydroides elegans (Haswell, 1883), and its possible applications in bioantifouling. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 817-23. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Huang, Z.O., Yan, S.K., Lin, S. and Zheng, D.Q. 1992. Biofouling communities on pier pilings in Mirs Bay, Hong Kong. In The Marine Flora and Fauna of Hong Kong and Southern China III (ed. B. Morton), 529-44. Proceedings of the Fourth International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1989. l::Iong Kong: Hong Kong University Press. Hutchings, P.A. 1990. Terebellidae (Poly chaeta) from the Hong Kong region. In The Marine Flora and Fauna of Hong Kong and Southern China Il (ed. B. Morton), 337-418. Proceedings of the Second International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. Imajima, M. 1980. Polychaetes collected from Tokyo Bay. Marine Fouling 2:23-8. Liao, C.O. 1981. Development and settlement of the larvae of the Hydroides ezoensis. Journal of Shandong College of Oceanology 11 :39-

51. (In Chinese) Mackie, A.S.Y. 1990. The Poecilochaetidae and Trochochaetidae (Annelida: Polychaeta) of Hong Kong. In The Marine Flora and Fauna of Hong Kong Southern China II (ed. B. Morton), 337-62. Proceedings of the Second International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. Mackie, A.S.Y. 1991. A new species of Scoloplos (Polychaeta: Orbiniidae) from Hong Kong and a comparison with the closely related Scoloplos marsupialis Southern, 1921 from India. Asian Marine Biology 8:35-44. Mackie, A.S.Y. and Hartley, J.P. 1990. Prionospio saccifera sp. nov. (Polychaeta: Spionidae) from Hong Kong and the Red Sea with a redescription of Prionospio ehlersi Fauvel, 1928. In The Marine Flora and Fauna of Hong Kong and southern China Il (ed. B. Morton), 363-75. Proceedings of the Second International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. Mak, P.M.S. 1982. The coral associated polychaetes of Hong Kong, with special reference to the serpulids. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 595617. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Mak, P .M.S. and Huang, Z.G. 1982. Studies on biofouling in Tolo Harbour. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 76787. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Morton, B. 1982. An introduction to Hong Kong's 11

J.J. Wang & Z.G. Huang

marine environment with special reference to the north-eastern New Territories. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 25-53. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Morton, B. 1987. Recent marine introductions into Hong Kong. Bulletin of Marine Science 41:503-13. Ohwada, T. 1992. A new species of Aglaophamus (Polychaeta: Nephtyidae) from Hong Kong. In The Marine Flora and Fauna of Hong Kong and Southern China III (ed. B. Morton), 149-56. Proceedings of the Fourth International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1989. Hong Kong: Hong Kong University Press. Shin, P.K.S. 1982. Some polychaetous annelids from Hong Kong waters. In The Marine

12

Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 16172. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Vrijmoed, L.L.P. 1973. An analysis of surface fouling organisms in the coastal waters of Hong Kong. In Proceedings of the Pacific Science Association Special Symposium on Marine Sciences, Hong Kong, 1973 (ed. B. Morton), 129-35. Hong Kong: Government Printer. Vrijmoed, L.P., Hodgkiss, I.J. and Thrower, L.B. 1986. Effects of surface fouling organisms on the occurrence of fungi on submerged blocks in Hong Kong coastal waters. Hydrobiologia 135:123-30. Yang, D.J. and Sun, R.P. 1988. Polychaetous Annelids Commonly Seen from the Chinese Waters. Beijing: China Agricultural Press. (In Chinese)

Asian Marine Biology 10 (1993): 13-26

FOUR NEW SPECIES OF CUMACEA FROM PETER THE GREAT BAY, SEA OF JAPAN Ludmila A. Tzareva and Stella V. Vassilenko Far East State Marine Reserve, Institute of Marine Biology, Russian Academy of Sciences, Vladivostok 690041, Russia Department of Hydrobiology, Zoological Institute, Russian Academy of Sciences, St Petersburg 199034, Russia

Abstract Four new species of Cumacea belonging to three families: Lampropidae, Nannastacidae, Bodotriidae (Lamprops pseudosarsi, L. lomakinae, Cumella kepeli, Bodotria ozolinshi) are described from the southern part of Peter the Great Bay, Sea of Japan.

Introduction The cumacean fauna of Peter the Great Bay and its shallow waters, in particular, is still poorly studied. Of 50 cumaceans found all over the Sea of Japan, 24 species were collected from depths of between 0.8-760 m in Peter the Great Bay and adjacent waters of the Sea of Japan, and only nine species in the upper sublittoral zone at depths of between 1 to 50 m (Lomakina 1958). Recent investigations have added two more subtropical species to the list; these are Lamprops japonica and Bodotria chinensis. The Pacific species Cumella vulgaris (Lomakina 1971) is widespread in Possjet Bay, Sea of Japan. In addition to the four new species described earlier, Diastylis paralaskensis, Dimorphostylis sculpturensis, Eudorellopsis leuconi and Pavlovskeola bicostata, belonging to three families (Diastylidae, Leuconidae, Nannastacidae) (Vassilenko and Tzareva 1990), the collections contained four more new species of Cumacea belonging to three genera and three families (Lampropidae, Nannastacidae, Bodotriidae). All type specimens are deposited in the Zoological Institute, Russian Academy of Sciences, St Petersburg (ZIN). The material was processed by L.A. Tzareva. Doubtful cases of identification of Cumacea were

studied in the Zoological Institute (St Petersburg). The use of Russian and foreign literature data on Cumacea and a comparative analysis of related species from collections of the Zoological Institute have allowed the authors to establish four cumacean species new to science.

Description of Species Lampropidae Lamprops pseudosarsi sp. novo (Figs. 1-3)

Material examined. Holotype (ZIN N 1187001) is a female of length 4.2 mm with a marsupium containing embryos, and three female Paratypes (ZIN N 1187002) of lengths 4.3 mm; 4.2 mm; 4.1 mm; 2.06.1985, Sea of Japan, Peter the Great Bay, 42°38'N, 131°12'E, depth 10 m, collector A. Ozolinsh, using the bottom sampling grab 'Okean' 0.25 m2 • Description. Female holotype. Carapace narrows relatively sharply in the front part and ends as a somewhat elongate pseudorostrum slightly upturned in lateral view. Antero-Iateral angles are poorly pronounced. Carapace has two distinctly marked curved folds. Carina along the mid-line of

L.A. Tzareva & S.V. Vassilenko

Fig. 1. Lamprops pseudosarsi sp. novo Adult female (Holotype ZIN N 1/87001 ),4.2 mm: A, dorsal; 8, pleotelson, dorsal; C, lateral.

14

New Cumacea from the Sea of Japan

B

) e o·

c Fig. 2. Lamprops pseudosarsi sp. novo Adult female (Holotype): A, pereopod 1; S, antenna 2; pereopod 2.

e, 15

o

(,)

3 3

Fig. 3.

Lamprops pseudosarsi sp. novo Adult female (Holotype): A, pereopod 5; 8 , pereopod 4. Lamprops sarsi Derzhavin: C, pleotelson , dorsal.

the carapace continues further as a longitudinal rhombic groove in the first third which is as long as one-third of the carapace length. Posterior portion of the carapace is fringed with a subround ridge. Carapace length is a little less than a quarter of the total body length. First three pectoral segments have transverse medial ridges and a median carina, disappearing on the third segment. Abdomen is shorter than half of the total body 16

length. Basis of pereopod 1 in length is slightly shorter than the length of all the other distal segments together but is 0.6 as long as the 2 distal articles together. Basis of P2 curves in the distal part and is 0.8 as long as the length of the other segments together. P3 is a little longer than P4 and their construction is similar. PS is short and bears long and thick setae. Telson is I.S times longer than the last abdominal segment and bears five

New Cumacea from the Sea of Japan

smooth setae. The middle seta is twice as long as the terminal ones, which are also twice as long as the intermediate. Uropodal peduncle is slightly longer than the telson. Endopodite slightly longer than both distal articles together. First and second articles bear 8 to 9 spines on inner margin and distal article ends in 2 spines, unequal in length. Exopodite is a little shorter than the peduncle and endopodite; its two articles are nearly equally long; they have long plumose setae on the inner margin and one long and one short apical seta (0.3 as long); setal ends split and provided with a long hair in the middle.

Remarks. This species is most closely allied to Lamprops sarsi Derzhavin, 1926. Since we have been able to compare our specimens with those collected by Lomakina from Kamchatka, Sea of Okhotsk and the Tartar Strait and described by Derzhavin and Lomakina, we have identified certain characters which allow us to separate the new species. Lamprops sarsi (Derzhavin 1926) redescribed by Gamo (1965) from Akkeshi Bay, in spite of differences from Derzhavin's specimens strongly differs also from ours. The following characters allowed us to separate the new species: 1. Body is shorter than that of Derzhavin' s specimen but as long as the specimen described by Gamo. 2. Carapace with two distinct folds; they are smooth in Lomakina's specimen while in Gamo's specimen there is only one distinct fold. Rostrum bent slightly upwards. 3. Rear of carapace and first three thoracic segments bear transverse median ridges. 4. First three thoracic segments with median carina. 5. Basis of PI much shorter than other distal articles together, while in Derzhavin's specimen the basis is longer. Carpus as long as ischium and merus together, while in Derzhavin's specimen the carpus is considerably longer. Dactylus 1.6 times longer than propus, while in Derzhavin's specimen the dactylus is one-third shorter than the prop us . 6. Basis of P2 bent and slightly longer than all other articles together, while in Derzhavin's specimen it is shorter and straight.

Carpus somewhat shorter than the two distal articles together, while in Derzhavin's specimen it is much longer than these two articles together. 7. Telson is 1.5 times longer than the last thoracic segment, while in Derzhavin's specimen it is more than twice as long. Its distal portion is three times as long as the proximal one while Derzhavin's specimen is five times narrower. Its end bears smooth spines unequal in length, while in Derzhavin's specimen there are knife-shaped plumose setae of different sizes. 8. Terminal article of uropodal exopodite is nearly equal in length to the proximal article, while in Derzhavin's specimen the proximal article is 0.7 as long as the distal one. Terminal article of endopodite is slightly longer than the middle article; in Derzhavin' s specimen, the terminal one is 0.7 as long as the middle one.

Lamprops lomakinae sp. nov. (Figs. 4-5) Material. Holotype (ZIN N 1185301) is a female of length 7.5 mm with an empty marsupium; 27.07.1981, Sea of Japan, Peter the Great Bay, 42°29'N, 130°51 'E, depth 20 m; substrate: stones, sand, shingle; collector A. Ozolinsh, using bottom-sampling grab 'Okean' 0.25 m2 • Description. Female holotype. Carapace with obtuse rostrum. Subrostral notch vaguely marked. Anterior central part of carapace provided with faint carina, followed by a narrow longitudinal furrow which does not extend as far as the end of the posterior margin of the carapace. Carapace furnished with two lateral distinctly pronounced oblique folds: first one begins beyond the border of the frontal region and before the longitudinal furrow bends upwards near the dorsal carina; second fold parallel with first, beginning from lower part of the subrostral notch. Second and third thoracic segments bear marked carina. Abdomen slightly longer than thorax. Pereopod 1 slender, seventh article 0.5 as long as and narrower than the fifth. P2 articles provided with numerous setae and spines, fifth longest and nearly as long as the combined length of the sixth and seventh together. P3 and P4 are similar in structure. 17

L.A. Tzareva & S.V. Vassilenko

Fig. 4. Lamprops lomakinae sp. novo Adult female (Holotype): A, pleotelson, dorsal; S, lateral; C, carapace, dorsal; 0, maxilliped; E, pereopod 4. 18

New Cumacea from the Sea of Japan

Fig. 5. Lamprops /omakinae sp. novo Adult female (Holotype): A, antenna; B, pereopod 1; C, pereopod 3; D, pereopod 5; E, pereopod 2.

19

L.A. Tzareva & S.V. Vassilenko

Telson markedly shorter than uropodal peduncle, gradually tapering terminally, bearing 5 terminal spines of which the middle is longest, and the two marginal spines are slightly shorter than the middle ones. Uropodal peduncles longer than the inner branch; inner uropodal branch markedly longer than the outer. First article of the inner branch longest, exceeding the combined length of the next two articles; the first and second articles of the inner branch bear a row of spines along the inner margin, becoming longer towards the distal end, first article provided with 7 spines, second with 5 spines, third without lateral spines and terminating in two thin setae; outer branch consists of two narrow articles, which are beset with thin setae along the inner border and at the distal end.

Remarks. The new species is most similar to Lamprops sarsi but differs from the latter by its larger size, obtuse pseudorostrum (L. sarsi has a sharp pseudorostrum), more pronounced 2 oblique folds (in L. sarsi the folds are faint), the presence of a longitudinal furrow on the carapace, which is absent in L. sarsi, end of telson is less tapered, with different relative lengths of the telson's apical spines (shortest spines in L. lomakinae are the two marginal spines, in L. sarsi they are the two middle spines). Second and third thoracic segments bear well-pronounced carina in the middle. N annastacidae Cumella kepeli sp. nov. (Figs. 6-7)

Material. Holotype (ZIN N 1185302) is a female of length 3.2 mm with a marsupium; 03.08.1977, Sea of Japan, south-western Sakhalin, 48°15.3'N, 141°35.4'E, depth 100 m, substrate: silt/sand, collector V. Gulbin. Paratypes (ZIN N 2/85303), 2 juvenile females, length 2.65 and 2.5 mm, Sea of Japan, Peter the Great Bay, Bolshoy Pelis Island (RimskyKorsakov Islands), 27.07.1986, depth 30-35 m, collector A. Ansulevich. Description. Carapace elongate, twice as long as 20

broad when viewed from above, with dorsal hump in the middle, with a dorsal carina along the entire carapace length, bearing in the anterior portion usually 4 sometimes up to 6 spines directed forward (young specimens 3 mm long have one spine and a carina with ill-defined denticles on the posterior portion of the carapace). Lateral borders of carapace each with one small nodule at the posterior border of the frontal region and two roundish large tubercles, one below the posterior border of the frontal region, the other larger one behind the first, in the mid-lateral portion of the carapace; upper portion of the carapace compressed laterally between these nodules, which may be observed from above. Anterior lower margin of carapace dentate. Subrostral notch relatively deep. Last free thoracic segment and first three abdominal segments each provided with two roundish lobes projecting upwards. Fifth abdominal segment is fringed with a transverse furrow in the posterior half. Pereopods 1 with basal article thickened in the middle portion, margins non-dentate, fifth article considerably longer than sixth. P2 with thickened basal article, seventh article twice as long as sixth. P3, P4 and P5 are similar in structure, with few setae and thick, claw-shaped, setae at the tip of the seventh article. Uropods are shorter than last three abdominal segments together, peduncle dentate along the inner border, outer ramus considerably shorter and narrower than the inner one; inner ramus bearing four spines along the inner margin and two spines (one long and one short) at the tip.

Remarks. The new species closely resembles Cumella dentata Lomakina, 1952. Examination of C. dentata holotypes allowed us to distinguish considerable differences between these species (Lomakina 1952). In C. kepeli, the carapace has two nodules and a depressed area between them (in C. dentata the carapace is round, without depressions and prominent nodules). In C. kepeli the carapace has a dorsal hump in the middle, clearly observed in lateral view; C. dentata lacks this hump on the carapace. C. kepeli is furnished with 4 to 6 spines on the dorsal carina only on the anterior part of the carapace; in C. dentata the

New Cumacea from the Sea of Japan

Fig. 6.

Cume/la kepe/i sp. novo Adult female (Holotype ZIN N 1/85302),3.2 m,: A, lateral; B, carapace, dorsal; C, uropod; D, pleotelson, dorsal; E, pereopod 1.

21

L.A. Tzareva & S.V. Vassilenko

Fig. 7. Cumella kepe/i sp. novo Adult female (Holotype): A, pereopod 2; B, pereopod 4; C, pereopod 5; D, pereopod 3. 22

New Cumacea from the Sea of Japan

dorsal carina has 10 to 20 spines along almost the entire length of the carapace. In C. kepeli, the basal articles of pereopods I distally have smooth margins; in C. dentata the lower margins of the basal article are dentate distallly. Bodotriidae Bodotria ozolinshi sp. novo (Figs. 8-9) Material. Holotype (ZIN N 1185304) an ovigerous female, length 3 mm; 27.03.1986, Peter the Great Bay, Sea of Japan; depth 32 m, substrate: silt/sand, collector A. Ozolinsh. Paratypes: 1 male with pleopods, 3.8 mm long (ZIN N 2/85305), Peter the Great Bay, Sea of Japan; 1 female 2.8 mm long with oostegite rudiments, and 1 male 2.8 mm long with underdeveloped pleopods (ZIN N 3/85306), Peter the Great Bay, Sea of Japan, 2.06.1985; depth 10 m, substrate: fine sand; two females 3 and 3.3 mm long, 1 male 2.7 mm long, with pleopod rudiments; 2 males 3.8 mm long with developed pleopods, (ZIN N 4/85307), Peter the Great Bay, Sea of Japan, 14.03.1987, depth 10 m, substrate: fine sand, collector A. Ozolinsh. Description. Female carapace elongate, with one dorsal median carina, each side with two lateral longitudinal folds, which do not reach the posterior margin of the carapace. First upper fold begins somewhat above subrostral notch, continues backwards, then bends towards the middle of the dorsal portion of the carapace, where right and left folds fuse somewhat at an angle; second lower fold is parallel to first, bends sharply upwards to first fold and fuses with it near posterior margin of the carapace. There is another short fold which connects the upper curve of the second fold with the posterior carapace margin. Two lateral longitudinal folds (upper and lower) are pronounced on the second thoracic segment and one longitudinal fold on third thoracic segment. Abdominal segements are narrower than thoracic ones, fifth abdominal segment longest, nearly twice as long as sixth. Pereopod 1 relatively short, fifth article shorter than sixth and seventh combined; fourth article

dentate on the upper edge. In P2, the third article is fused with the basal one and the terminal article is markedly longer than the preceding one. P3 and P4 are similar in structure. Uropodal peduncle somewhat longer than most abdominal segments, inner one-article ramus is shorter than the outer one, bearing 4 dentate and 2 apical spines (one long and the other short) on its inner edge. Male has a more robust and longer abdomen. Carapace sculpture in the male is similar to that of the female, but free thoracic segments lack longitudinal lateral folds. Uropodal peduncle is furnished with a row of long plumose setae along the lower-inner edge, inner ramus with 5 spinelike setae along the inner edge and one terminal elongate seta; outer ramus has long plumose setae along the inner edge. Remarks. This species closely resembles Bodotria chinensis Lomakina, 1960, but differs in that the lower longitudinal fold in B. ozolinshi does not reach as far as the posterior edge of the carapace; in B. chinensis it reaches to the end of the carapace (Lomakina 1960), the upper edge of the fourth articles of pereopods I is dentate; in B. chinensis the fourth articles of pereopods 1 lack dentation and the inner edge of the uropodal endopodites in males and females bears fewer spines and spine-like setae than in B. chinensis.

Discussion The material collected from July 1980 until July 1987 with the use of a bottom sampling grab 'Okean' from depths of 10 to 63 m in different parts of the Far East State Marine Reserve situated in the southern Peter the Great Bay of the Sea of Japan is of considerable interest. Our study has expanded by nearly two times the list of Cumacea species known from Peter the Great Bay. Our collection also includes other new species, but we have no opportunity to describe them because they are either represented by only single specimens or are badly damaged. In the Far East State Marine Reserve we have collected 30 cumaceans belonging to 9 genera and 5 families. Of these, 11 species (one-third of all cumaceans found in the area) are new. More than

23

L.A. Tzareva & S.V. Vassilenko

8

1

0 .1 mm

I

Fig. 8. Bodotria ozolinshi sp. novo Adult female (Holotype ZIN N 1/85304), 3 mm: A, lateral; B, pereopod 3; C, pereopod 1; 0, dorsal; E, pereopod 4; F, pereopod 5.

24

New Cumacea from the Sea of Japan

E

Fig. 9. Bodotria ozolinshi sp. novo Adult male (Paratype ZIN N 2/85305), 3.8 mm: A, lateral; S, maxilliped 3; C, antenna 2; D, pereopod 1; E, antennal; F, pereopod 2; G, pereopod 3; H, pereopod 5; I, pereopod 4; J, pleopod 1; K, uropod.

25

L.A. Tzareva & S.V. Vassilenko

a half of the entire cumacean fauna of the area comprises relatively warm-water (low-boreal) species; the new species are also low boreal and are mostly assigned to warm-water genera. The pattern of vertical distribution of Cumacea is as follows: a majority of warm-water species (low-boreal and subtropical) occur from the

intertidal zone down to 32 m depth; the share of low-boreal species markedly decreases from 32 to 63 m and 47 to 63 m depths are inhabited by boreal-arctic species. Wide-boreal and amphiboreal species occur over the depth range of 10 to 63 m.

References Derzhavin, A.H. 1926. The Cumacea of the Kamchatka expedition. Russian Hydrobiological Journal 5:7-9, 174-82. (In Russian) Gamo, S. 1965. Cumacean Crustacea from Akkeshi Bay, Hokkaido. Publications of the Seto Marine Biological Laboratory 8: 187219. Lomakina, N.B. 1952. New species of cumacean Crustacea from Far Eastern seas. Proceedings of the Zoological Society, Leningrad 12: 15570. (In Russian) Lomakina, N.B. 1958. Cumacea of the Seas of U.S.S.R. Publication of the Academy of Sciences, Moscow, U.S.S.R. No. 66. (In

26

Russian) Lomakina, N.B. 1960. On fauna Cumacea (Crustacea, Malacostraca) coastal zone of Yellow Sea. Oceanologia et Limnologia Sinica 3(2):94-114. (In Russian) Lomakina, N.B. 1971. Cumacean Crustacea (Cumacea) from Possjet Bay, Sea of Japan. Research of the Sea Fauna 8: 182-4. (In Russian) Vassilenko, S.V. and Tzareva, L.A. 1990. New species of Cumacea from the south part of Peter the Great Bay, Sea of Japan. Proceedings of the Zoological Institute, Leningrad 218:54-74. (In Russian)

Asian Marine Biology 10 (1993): 27-40

THE EFFECTS OF PHYSICAL FACTORS AND GRAZING BY LIMPETS ON THE COLONIZATION, GROWTH AND COMPOSITION OF INTERTIDAL ALGAE ON A ROCKY SHORE AT CAPE D' AGUILAR, HONG KONG J.H. Liu The Swire Marine Laboratory, The University of Hong Kong, Hong Kong

Abstract The effects of grazing by Cellana toreuma and Patelloida saccharina at natural densities and at different tidal levels on the colonization and growth of algae in cleared areas were determined by means of herbivore inclusion/exclusion cages on a moderately exposed rocky shore at Cape d' Aguilar, Hong Kong, between October 1990 and May 1991. In grazer-excluded plots, algae occupied quickly all the substratum and grew rapidly. Removing limpets resulted in the establishment of opportunistic species of algae, i.e., Acrochaetium robustum, Bangia fuscopurpurea, Porphyra dentata and Viva iactuca at + 2 m C.D., during the cooler months of the year; they still disappeared in May, however. Encrusting algae, i.e., Gomontia sp. and Hildenbrandia prototypus, formed an algal film, following exclusion of limpets, at + I m C.D. so that algal cover was rather stable over the experimental period. Algal biomass (chlorophyll a; J..lg·cm- 2 ) in ungrazed plots showed a distinct seasonal pattern at + 2 m C.D. Biomass generally increased throughout the experimental period at + I m C.D. In all the open and limpet-enclosed plots, algal cover and biomass were reduced to low levels throughout the experimental period. Algal species composition was different in vertically and horizontally oriented cages. This may be due to the differential effects of waves upon the shore and cage effects. Two-factor analysis of variance of algal percentage cover and chlorophyll a content for each month at both + I m and + 2 m C.D. levels with different grazing treatments showed there to be significant differences between treatments and between months. An S.N.K. test showed that there was a significant difference between ungrazed and grazed plots both by limpets (Cellana or Patelloida) and by all herbivores (open cages). There was, conversely, no significant difference between grazed cages, i.e., grazed by either Cellana or Patelloida or by all herbivores. A statistically significant seasonal pattern of algal biomass characterises the shore. In Hong Kong, limpet grazing has a significant impact on the colonization and growth of intertidal algae, also causing a change in species composition and richness. Physical factors also have a great impact on algal biomass, however, especially at higher tidal levels in summer.

Introduction The species composition and abundance of algae on rocky shores is influenced both by physical factors and biological interactions such as grazing and competition. Marine plant-herbivore relations have been studied for many years (see reviews of early work by Lubchenco and Gaines 1981; Hawkins and Hartnoll 1983; Hawkins et ai. 1992

and Vadas and Elner 1992). Limpets are important herbivores on most shores and in shallow subtidal waters (Underwood 1979; Branch 1981). Their impact on algal abundance and community structure has received much attention (Jones 1948; Southward 1964; Black 1976; Nicotri 1977; Hay 1979; Kitting 1980; Underwood 1980; Underwood and lernakoff 1981; Hawkins 1981 a, b; Steneck 1982; lernakoff 1983, 1985; lara and Moreno

J.H. Liu

1984; Cubit 1984; Farrell 1988). After either removal or exclusion of limpets, opportunistic species of algae proliferate (Underwood 1980; Underwood and lernakoff 1981; Cubit 1984; Farrell 1988), the abundance of large species, such as fucoids can increase (Hawkins 1981 b, 1983) and species diversity and composition can change (Nicotri 1977; lernakoff 1983). The effects of physical stress resulting from low tide emersion, i.e., desiccation, extremes of temperature and variations in light intensity, are also important factors regulating the distribution and abundance of a number of intertidal algae, particularly at higher levels (Lewis 1964; Frank 1965; Chapman 1973; Underwood 1980, 1981). It has been concluded that the summer disappearance of some algae is a direct result of mortality caused by physical stresses (Castenholz 1961; Haven 1973; Hawkins and HartnolI 1983, 1985), a conclusion also reached by Hodgkiss (1984) with regard to Hong Kong shores. Surprisingly few studies have looked at the interaction between physical factors and grazing. The most comprehensive study is that of Cubit (1984) who examined the contribution made by herbivory to seasonal variations in algal cover at the uppermost intertidal levels of a rocky shore on the coast of Oregon. Hong Kong is ideal for studies of this kind because of extreme seasonal fluctuations in climate. From October to April, when rocky intertidal habitats are relatively wet, cool and protected from intense sunlight, fastgrowing algae (blue-green algae, diatoms, filamentous and membranous species of red and green algae) and macroalgae cover them. During the hot, dry and more sunny summer, algae disappear, leaving the middle and high shore with only patches of encrusting species (Liu 1992). It is hypothesized that grazing by herbivores, particularly limpets, may be responsible for the sparseness or absence of intertidal algae in Hong Kong; conversely, physical factors may contribute to seasonal fluctuations in intertidal algae biomass by affecting rates of production. The aim of the present work was to determine the effects of grazing by limpets, i.e., Cellana toreuma (Reeve) and Patelloida saccharina (Linnaeus), on the colonization, growth and composition of an intertidal algal community at Cape d' Aguilar,

28

Hong Kong. To examine the interaction between physical and biotic factors, two tidal levels were chosen with the experiment being conducted from autumn (October) to early summer (May) and covering the period when algae, naturally, cover the shore. To achieve this, a series of cage experiments was established to either contain or exclude herbivores from randomly chosen areas. Algal percentage cover, species richness and composition and chlorophyll a (Jlg.cm- 2 ) were recorded monthly.

Materials and methods The site and species studied The study site is located on the northern shore of Lobster Bay at Cape d' Aguilar, Hong Kong Island (Fig. 1). The site is exposed to moderate wave action and, facing south, is illuminated constantly during the hours of daylight. The shores of Cape d' Aguilar are of coarse tuff (AlIen and Stephens 1971). The mean tidal range in Hong Kong is 1.5 m, though extreme spring tides have a range of 2.8 m (Morton 1982). The study area delineated was between 1 m and 2 m above chart datum, i.e., the eulittoral zone, and was thus awash for approximately 50% of the time. The shore had a great number of limpets and other herbivores as described in Table 1. The rocky shore chosen for study had a rather simple algal community. Sargassum hemiphyllum (Turn.) C. Agardh, was abundant on the lower shore during the less sun-exposed and cooler winter, i.e., from December to March, but was absent in the sunnier and hotter conditions of summer. Encrusting algae were, however, present throughout the year both on the lower shore, i.e., a pink Lithophyllum crust (> 70%), and on the middle shore, where patches of Hildenbrandia prototypus Nardo, Branchytrichia maculans Gomont and Gomontia sp. covered some 10% of the rock surface. Limpets, the predominant herbi vores of the shore, were present year round.

General methods and cage structure The experiments and sampling were carried out at both lower and higher levels of the middle shore,

The effects of grazing by Gel/ana and Patel/oida

HONG I
TAl lAM BAY .

.

.....

"

Fig. 1. A map of Cape d'Aguilar, Hong Kong, showing the location of the study site.

Table 1. Mean densities of limpets and other herbivores on the experimental shore. Mean ± S.D. n = 20. Height above C.D.(m)

Species

Gellana toreuma Patelloida saccharina Nerita albicilla Monodonta labio Lio/ophura japonica 2

Gellana toreuma Nodilittorina vidua Nerita albicilla Monodonta labio Lio/ophura japonica

Individuals.0.05 m·2 (± S.D.) 10.1 9.2 4.4 1.0 0.8

(4.006) (1.542) (1.698) (0.858) (0.834)

2.3 1.3 0.9 0.3 1.0

(1.164) (1.129) (0.852) (0.470) (0.649)

29

J.H. Liu

i.e., at + 1 m and + 2 m C.D. Cages used in the experiments were made of metal netting of 0.5 x 0.5 cm mesh size and were 23 x 23 cm and 4 cm high, i.e., they enclosed an area of - 0.05 m 2 • The cages were fastened to the rock by metal screws and rawlplugs. Gaps between the substratum and the base of a cage were loosely sealed to allow for drainage with a non-toxic DEVCON wet surface repair putty (UW). The experimental areas were first cleared of all organisms by scraping with a knife and a wire brush. Experimental animals were removed carefully from adjacent areas and transferred to the experimental cages. All the cages were checked every 2 to 3 days when dead animals were replaced by equivalent-sized conspecifics and damaged cages repaired. The percentage cover of all visible algae was assessed using a 0.05 m 2 quadrat divided into a grid of 100 evenly-spaced points, and counted as the number of points lying over the algae. Chlorophyll a analysis was used to estimate algal abundance. Between 5-6 randomly-chosen rock samples, each of 1 cm 2 , were chipped from the rock surface of each experimental cage. Samples were analysed within 24 hours of collection, usually after overnight storage in an air-tight and light-sealed container placed in a refrigerator (4°C). Exposure to strong light and high temperatures was also avoided in transit. Chlorophyll a was extracted from each set of rock chips using hot methanol (HMSO 1986). The absorbance of the methanol extract was measured at wavelengths of 665 and 750 nm using a PYE UNICAM PU 8600 UV /VIS spectrophotometer. The absorbance value obtained at 750 nm was subtracted from that obtained at 665 nm and this value can be designated A and used as a correction for turbidity. Calculation of the results followed the formula: 13.9 x A x v Chlorophyll a

=-----~

dxV (HMSO 1986) content of the sample Where A = absorbance v = volume of solvent in mL V = area of rock sampled in cm 2

30

d = cell path length in cm (4.0) and 13.9 = constant

Experimental design Mean densities of limpets and other herbivores on the experimental shore were determined in 20 randomly-thrown quadrats (Table 1). The effects of grazing by either different species of limpets, i.e., Cellana toreuma and Patelloida saccharina, or all herbivores at the natural densities determined above and at different tidal levels on the colonization and growth of algae in cleared areas were determined. Cages were used either to exclude all herbivores (ungrazed plots), and thus prevent grazing, or to enclose limpets (limpetgrazed plots) and thus ensure that the plots were grazed only by limpets. Partial cages (open plots) were also established to allow all herbivores to graze and to serve as the presence of cages themselves. Mean densities of limpets at + 1 m C.D. were 10.1 individuals·0.05 m- 2 for Cellana toreuma and 9.2 individuals·0.05 m· 2 for Patelloida saccharina. The mean density of Cellana toreuma at + 2 m C.D. was 3.0 individuals.0.05 m- 2 • U sing these densities as a guide, 7 grazing treatments were established in 21 experimental cages, i.e., three replicate cages of each treatment, which had been previously cleared of all organisms. These treatments were, on the lower middle shore (+ 1 m C.D.), (1) 10 ·Cellana toreuma (mean shell length 16 mm); (2) 9 Patelloida saccharina (mean shell length 9 mm) in the inclusion cages; (3) cages excluding all herbivores and (4) partial cages. On the higher middle shore (+ 2 m C.D.) they were: (5) 3 Cellana toreuma (mean shell length 16 mm) in the inclusion cages; (6) cages excluding all herbivores and (7) partial cages. It is acknowledged that not all experimental cages were located on a similar slope on the shore, i.e., they did not face the same degree of wave action. They were, instead, categorized as either vertical cages (facing wave action) or horizontal cages (protected from direct wave action). The algal species composition and their sequence of appearance in these cages were different. These data are presented in Table 2 and were not used

The effects of grazing by Gel/ana and Patel/oida

for the estimates of algal percentage cover and chlorophyll a content, i.e., this was not a treatment variable. The experiments commenced on the 27 October 1990 and continued for seven months. The percentage cover and chlorophyll a content of algae in the experimental areas were determined every month. Algal percentage cover and chlorophyll a content for each month were analysed by a two factor (treatment and month) analysis of variance and the means tested by an S.N.K. test.

Results Ungrazed controls

In all the exclusion cages at + 1 m C.D., Gomontia sp. formed a thin algal film within one month following the exclusion of all herbivores. Hildenbrandia prototypus also grew in small amounts within two months following the exclusion and thereafter increased slowly. Algal cover was, however, rather stable during the experimental period (Fig. 2).

At + 2 m C.D., all the exclusion plots were colonized by either Acrochaetium robustum Boergesen (vertical cages) or Gomontia sp. (horizontal cages) during the first month. Bangia Juscopurpurea (Dillw.) Lyngbye (vertical cages) and Porphyra dentata Kjellman (horizontal cages) dominated those areas between December and February. In April, all the ephemeral macro algae died back and were replaced by mainly encrusting algae, i.e., Gomontia sp., in the vertical cages and Hildenbrandia prototypus and Gomontia sp. in the horizontal cages (Table 2). Algal species composition was different in the vertical and horizontal cages (Table 2). There were only three species of algae in the vertical cages but five in the horizontal cages. This may be due to the differential effects of waves on the shore and cages. Again, algal cover was rather stable during the experimental period (Fig. 3). Algal biomass in the exclusion plots at + 2 m C.D. varied seasonally. The amount of chlorophyll a (Jlg·cm2) gives an approximate indication of algal biomass present. Figures 4 and 5 show calculated values of chlorophyll a (Jlg·cm- 2). Algal biomass formed a peak in February and decreased abruptly

100

0 .. ·· ...... ·0· .. · ..

Q)

0 (J'l

0

1

L-

>

1:' 1

T .. 0 ...... 0 D····

0

Q)

I 1

80

'+-

60

0

0·····0 ungrazed

Q)

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u (J'l

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LQ)

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0....

0

o

N

1990

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J

F

M A

M

1991

Fig. 2. Mean (± S.D.) percentage cover of algae in lower middle shore experimental plots (+ 1 m C.D.). 31

w

~

I

N

r

Table 2. Sequence of appearance of algal species in all the experimental cages during the experimental period: percentage cover. Treatment above C.D.

Height

Ungrazed plots

2

Algal species

Month

1

2

3

4

5

6

7

Nov.

Dec.

Jan.

Feb.

Mar.

Apr.

May

95

99

100

87 11

89 3

Acrochaetium robustum Bangia fuscopurpurea Gomontia sp.

100

Gomontia sp. Porphyra dentata Bangia fuscopurpurea Viva lactuca Hildenbrandia prototypus

92

Gomontia sp. Hildenbrandia prototypus

73

(V)

69 5

62 11

Gomontia sp. Hildenbrandia prototypus

67

(H)

70 3

Gomontia sp. Porphyra dentata Hildenbrandia prototypus

1

3

1

Gomontia sp. Hildenbrandia prototypus

0

1

2

4 5

Grazed by Patelloida saccharina

1

Gomontia sp. Hildenbrandia prototypus

0

3

4

Open plots

2

Gomontia sp. Hildenbrandia prototypus

3

3 1

Gomontia sp. Hildenbrandia prototypus

4

(V)

(H)

1

Grazed by Gel/ana toreuma

2

1 - - - -

--

--

93 5 92

- -

- -

7 ----

76

75

3 7

12

15

60 38

42 57

29 70

19 81

67 7

87 10

87 12

84 13

85 15

5 3

11 17

7 6

2

1

4

5

6 3

4 1

0 5

13

12 2

7 6

4 5

2

4 4

5 1

3 1

5 2

1 3

8 4

7 4

5

2 1

25 69 5

-

88 12

70 15

-

------

c·

The effects of grazing by Gel/ana and Patel/oida

100

O.. ····D...... D......

ID

g ..... ~...... g

0

1

(Jl

0

80

0·······0 0·······0

60

T--T

'+-

0 L

ID

>

ungrazed grazed by Gel/ana toreuma open plot

0

U ID (Jl

0

40

........

T

C ID

U L

ID

o

'r

20

·.T

:

CL

()

T

0

.•

···T/

~l!5-T

o N

D

1990

O.

T

=t= .....

T

T

-T_9~l!5

J F 1991

1

I

M A

M

Fig. 3. Mean (± S.D.) percentage cover of algae in higher middle shore experimental plots (+ 2 m C.D.).

afterwards at + 2 m C.D. (Fig. 5). Algal biomass increased during the experimental period at + 1 m C.D. (Fig. 4).

considerable amount « 20%) of encrusting algae (Hildenbrandia prototypus and Gomontia sp.) was present in the + 1 m C.D. cages between February and April.

Grazing by all herbivores (open cages)

In the open cages, where grazing by all herbivores was possible, algal cover (%) and biomass (chlorophyll a; J-Lg·cm- 2 ) were reduced to low levels throughout the experimental period (Figs. 2-5). A few algae, i.e., the encrusting Hildenbrandia prototypus and Gomontia sp., did, however, sustain a presence in these cages. Grazing by Cellana toreuma Cellana toreuma kept the algal cover (%) and biomass (chlorophyll a; J-Lg·cm 2 ) to low levels throughout the experimental period at both + 1 m and + 2 m C.D. (Figs. 2-5). Between January and March, a small area of substratum « 20%) was covered by Porphyra dentata in the cages at + 2 m C.D. in which 3 Cellana toreuma were enclosed, but thereafter disappeared. Porphyra dentata did not occur in the + 1 m C.D. cages. A

Grazing by Patelloida saccharina

Like Cellana toreuma, Patelloida saccharina reduced algal cover (%) and biomass (chlorophyll a; J-Lg·cm 2 ) to low levels, i.e., < 15% and < 3 J.lg·cm- 2, respectively, over the experimental period (Figs. 2 and 4). Algae growing in these grazed plots were largely encrusting species of Hildenbrandia prototypus and Gomontia sp. Two-factor analysis of variance of algal percentage cover and chlorophyll a content for each month at both + 1 m and + 2 m C.D. levels with different grazing treatments shows that there were significant difference between treatments and between months (Tables 3-6). The S.N.K. tests showed that there was a significant difference between ungrazed and grazed plots both by limpets (closed cages containing either Cellana or Patelloida) and by all herbivores (open cages). There was, conversely, no significant difference between the 33

J.H. Liu

15~------------------------------'

D······ 0 ungrazed 0······ 0 grazed by Gel/ana toreuma

~

N

I

'Y open plot • - . grazed by Patel/oida saccharina

'Y -

E

~10 :::t "'-...../

T...... ·~

(J)

T

0 ....... 0

1

.··1

d ~

...c

Cl..

o 5L o

...c U

Fig. 4. Mean (± S.D.) chlorophyll a values (Jlg·cm o2 ) for lower middle shore experimental plots (+ 1 m C.D.). Although the starting point in October 1990 is taken as zero chlorophyll a, it is acknowledged that the initial removal method could not have removed all algal cells.

25~--------------------------------~

~

~

0·····0 ungrazed

N o · · · · · 0 grazed by Gel/ana :L.. I 20 toreuma .

E

'Y-'Y

o

open plot

(J)

::3..15 -

"'-...../

d

~

:.L

£10Cl.. o L o ...c 5U

o

1990

N

D

J

F

M

A

M

1991

Fig. 5. Mean (± S.D.) chlorophyll a values (Jlg·cm o2 ) for higher middle shore experimental plots (+ 2 m C.D.). Although the starting point in October 1990 is taken as zero chlorophyll a, it is acknowledged that the initial removal method could not have removed all algal cells. 34

The effects of grazing by Cel/ana and Patel/oida

grazed cages, i.e., grazed by either Cellana or Patelloida, and those grazed by all herbivores (Tables 3-6). The S.N.K. tests also showed that there was a significant difference between February and most other months for both algal percentage cover and chlorophyll a at + 2 m C.D. (Table 4 and 6). The results of the S.N.K. tests showed that algal percentage cover and chlorophyll a for February, March, April and May at + 1 m C.D. were grouped together with no significant difference between them. Similarly, algal percentage cover and chlorophyll a for November, December and Jannuary at + 1 m C.D. were grouped together with no significant difference between them. There was, moreover, a significant difference (P = 0.05) between the two groups (Tables 3 and 5).

Discussion The experiments show that grazing by both Cellana toreuma and Patelloida saccharina at natural densities has a great impact on the colonization and growth of algae, as compared with ungrazed plots. In the latter, algae occupied

all the substrata quickly and grew rapidly, especially during the winter months. Filamentous and membranous species of red and green algae grew in greater abundance and at higher shore levels from which grazers were experimentally excluded during the cooler months of the year, i.e., from December to February. Clearly, grazing by limpets prevents algal colonization at a time when they would normally be capable of colonizing this region of the shore. Data on the amount of chlorophyll a (f.lg·cm- 2) present on the rock surfaces of both grazer-excluded plots and grazer-enclosed plots also indicate that grazers greatly reduce algal standing biomass. The present work also shows that grazing by limpets causes a change in algal species richness and composition. Removing limpets resulted in the establishment of opportunistic species of algae, i.e., Acrochaetium robustum, Bangia fuscopurpurea, Porphyra dentata and Viva lactuca at + 2 m C.D., during the cooler months of the year. This suggests strongly that limpets eliminate the early stages of such ephemeral species at this tidal level. Grazing by limpets did not, however, eliminate the early stages of encrusting algae which occurred in all the grazed plots during the

Table 3. Two-factor analysis of variance of algal percentage cover for each month at + 1 m C.D. with different grazing treatments (*indicates a significant difference). Source of variation

OF

Seq SS

Adj Ms

Treatment Time TxT Error Total

3 6 18 56 83

57605.7 3914.0 2044.5 702.3 64266.5

19201.9 652.3 113.6 12.5

4 Feb. 34.71

Significant

0.000 0.000 0.000

1531.10 52.01 9.06

Treatment No. 1 2 3 10 Gel/ana 9 Patel/oida Grazing Ungrazed treatment 10.37 13.91 Mean % cover 73.32 S.N.K. tests (p = 0.05) on grazing treatment (numbers as above) 1>4=3=2 Time No. 2 3 Time Nov. Dec. Jan. Mean % cover 17.07 22.42 22.17 S.N.K. tests (p = 0.05) on time (numbers as above) 4=5=6=7>1=2=3

P

F

4 Open cages 14.59

5 Mar. 36.13

6 Apr. 31.98

7 May 31.85

35

J.H. Liu

Table 4. Two-factor analysis of variance of algal percentage cover for each month at + 2 m C.D. with different grazing treatments (*indicates a significant difference). Source of variation Treatment Time TxT Error Total

DF 2 6 12 42 62

P

F

Seq SS

Adj Ms

109975.5 993.7 827.4 364.7 112161.3

54987.7 165.6 69.0 8.7

Significant

0.000 0.000 0.000

6333.14 19.07 7.94

Treatment No. 1 2 3 3 Gellana Open cages Grazing Ungrazed treatment 11.37 15.80 79.55 Mean % cover S.N.K. tests (p = 0.05) on grazing treatment (numbers as above) 1> 2= 3 Time No. 2 3 Time Nov. Dec. Jan. 33.33 34.33 36.33 Mean % cover S.N.K. tests (p = 0.05) on time (numbers as above) 4>1=6=2=7=3 4=5 1=2=3=5=6=7

4 Feb. 45.33

5

6 Apr. 33.33

Mar. 38.67

7 May 34.78

Table 5. Two-factor analysis of variance of algal chlorophyll a content for each month at + 1 m C.D. with different grazing treatments (* indicates a significant difference). Source of variation

DF

Seq SS

Treatment Time TxT Error Total

3 6 18 56 83

349.363 43.512 83.476 19.726 496.078

Adj Ms 116.454 7.252 4.638 0.352

F

P

330.60 20.5 13.17

0.000 0.000 0.000

2 Treatment No. 1 3 9 Patelloida Grazing Ungrazed 10 Gel/ana treatment Mean chlorophyll a content 6.35 1.41 2.41 S.N.K. tests (p = 0.05) on grazing treatment (numbers as above) 1>4=3=2

Time No. 2 Time Nov. Dec. Mean chlorophyll a content 1.94 1.81 S.N.K. tests (p = 0.05) on time (numbers as above) 3=4=5=6=7 5=4=7>1=2 1 =2 =3 6>2 6 =1 36

Significant

4 Open cages 1.41

3 Jan.

4 Feb.

5

6

Mar.

Apr.

7 May

2.57

3.51

3.64

3.34

3.44

The effects of grazing by Gel/ana and Patel/oida

Table 6. Two-factor analysis of variance of algal chlorophyll a content for each month at + 2 m C.D. with different grazing treatments (* indicates a significant difference). Source of variation

OF

Seq SS

Treatment Time TxT Error Total

2 6 12 42 62

776.941 453.420 348.185 40.946 1619.491

Adj Ms 388.471 75.570 29.015 0.975

experimental period, but did reduce biomass. Such results are consistent with the findings of other authors (Lubchenco 1978~ Lubchenco and Gaines 1981 ~ Steneck 1982). Encrusting algae are, probably, more resistant to the effects of grazing by gastropods (Lubchenco and Cubit 1980~ Slocum 1980; Kitting 1980). Cubit (1984) found that a partial reduction in herbivory resulted in the development and persistence of a dense cover of algae throughout the summer months, as well as an overall increase in algal abundance during other times of the year. This author has also indicated that seasonal fluctuations in algal abundance result from variation in rates of algal production rather than from changes in either absolute rates of algal loss to herbivory or physical stresses. Seasonal fluctuations in the abundance of algae can be correlated with the degree of habitat exposure to the physical stresses of desiccation, solar radiation and high temperatures experienced during low tide. Physical factors have a great impact on algal biomass, especially at higher tidal levels on the

Significant

0.000 0.000 0.000

398.47 77.52 29.76

Treatment No. 1 2 3 Gel/ana Ungrazed Grazing treatment 10.22 2.78 Mean chlorophyll a content S.N.K. tests (p = 0.05) on grazing treatment (numbers as above) 1>2 = 3 2 Time No. Time Nov. Dec. Mean chlorophyll a content 2.45 2.89 S.N.K. tests (p = 0.05) on time (numbers as above) 4>5>1=2=6=7 2=3=6=7 4>5=3>1

P

F

3 Open cages 2.76

5

Jan.

4 Feb.

Mar.

6 Apr.

7 May

5.26

10.72

7.24

4.55

3.63

3

shore, where conditions are harsher. In the ungrazed plots at + 2 m C.D., algal biomass, in terms of chlorophyll a (J..Lg·cm- 2 ), showed a distinct seasonal pattern. The pattern has also been statistically identified for both algal percentage cover and chlorophyll a at this level on the shore (Tables 4 and 6). Algal biomass was higher during the cooler months of the year. Such a seasonal pattern is thought to be caused by variations in rates of algal production, which are related to seasonal changes in the physical environment (Hodgkiss 1984; Ho 1986), particularly with regard to temperature (Underwood and lernakoff 1984) and degree of wetting (John son et al. 1974; Quadir et al. 1979; Underwood and lernakoff 1984) during the daylight hours which, in turn, depend on weather conditions, variations in wave height and tidal patterns. In summer, high temperatures and desiccation create lower rates of algal production than in winter. An increased abundance of algae during the winter is unlikely to result from either a seasonal decrease in limpet population density or an interruption of grazing 37

J.H. Liu

activities, because there is at this time simultaneous increases in growth rate and reproductive activity (Liu 1992). Physical factors have little impact on the biomass of the encrusting alga Hildenbrandia prototypus at + I m C.D., where physical conditions are more benign. The biomass and percentage cover of Hildenbrandia prototypus in the un grazed plots at + 1 m C.D. generally increased throughout the experimental period. Acrochaetium robustum, Bangia juscopurpurea, Porphyra dentata and VIva lactuca Linnaeus were, moreover, present in winter and early spring in all grazer-excluded plots at + 2 m C.D., but also disappeared in May. Physical stress is thought to prevent the establishment of the algae during the summer. Such results suggest strongly that a harsh physical environment, especially during low tide, i.e., desiccation, high temperature and light intensity, are important in inhibiting the colonization and growth of intertidal macroalgae in Hong Kong. It was not anticipated that Porphyra dentata would occur in the three Cellana toreuma enclosed cages, even in small amounts « 20%), between January and March. Other ephemeral macroalgae did not. This is thought to be caused by: (I) the effects of the cages and (2) a reduced feeding by Cellana toreuma on the sporelings and young stages of this species, caused by their heavy settlement and higher rates of production. Shading, caused by cages, provides protection from desiccation, insolation and high temperatures. Cages also reduce the mechanical stress of wave action (Cubit 1984). Cages may, thus, provide more suitable conditions for the colonization of Porphyra dentata spores inside the cages even under grazing pressure. It is important to note that Porphyra dentata occurred (1) at higher levels on the shore (+ 2 m C.D.); (2) during the cooler months of the year; (3) in greater amounts in ungrazed plots between December and

March and in small amounts in the three Cellana toreuma grazed plots between January and March and (4) not in open plots which could be grazed by all herbivores. Porphyra dentata appeared in the three Cellana toreuma grazed plots one month later than in the ungrazed plots. It can be assumed that their limited elimination from the latter plots resulted from a reduced grazing level on the sporelings of Porphyra dentata. This allowed them to grow into adults when the heavy settlement and higher rates of production of this species occurred during the most suitable periods of the year, particularly under the protection of the effects of the cages. Limpets, in combination with other herbivores, may thus have a profound impact on the colonization and growth of Porphyra dentata on Hong Kong shores. The great differences in terms of algal biomass, species richness and composition between the grazed and ungrazed plots confirm that limpet grazing has a significant impact on the colonization and growth of intertidal algae in hong Kong. The growth of both ephemeral macroalgae and perennial encrusting algae increase when and where physical conditions are more benign, i.e., during the cooler months of the year and at lower levels on the shore. In conclusion, algal colonization and growth are determined primarily by the grazing of limpets, but are also influenced by physical factors modifying the rates of algal growth.

Acknowledgements I would like to thank my supervisors, Dr I.J. Hodgkiss and Prof. Brian Morton for their advice on this study and for the latters critical reading of the first drafts of the manuscript of this paper. This work forms a part of the thesis submitted to The University of Hong Kong for the degree of Doctor of Philosophy.

References Black, R. 1976. The effects of grazing by the limpet, Acmaea insessa, on the kelp, Egregia laevigata, in the intertidal zone. Ecology 57:265-77. 38

Branch, G .M. 1981. The biology of limpets: physical factors, energy flow, and ecological interactions. Oceanography and Marine Biology Annual Review 19:235-380.

The effects of grazing by Gel/ana and Patel/oida

Castenholz, R.W. 1961. The effect of grazing on marine littoral diatom populations. Ecology 42:783-94. Chapman, A.R.O. 1973. A critique of prevailing attitudes on the control of seaweed zonation on the sea shore. Botanica Marina 16:80-2. Cubit, J .D. 1984. Herbivory and the seasonal abundance of algae on a high intertidal rocky shore. Ecology 65:1904-17. Farrell, T.M. 1988. Community stability: effects of limpet removal and reintroduction in a rocky intertidal community. Oecologia 75: 190-7. Frank, P.W. 1965. The biodemography of an intertidal snail population. Ecology 46:83144. Haven, S.B. 1973. Competition for food between the intertidal gastropods Acmaea scabra and Acmaea digitalis. Ecology 54: 143-51. Hawkins, S.J. 1981 a. The influence of season and barnacle cover on algal colonization of Patella vulgata exclusion cages. Journal of Experimental Marine Biology and Ecology 61:1-15. Hawkins, S.J. 1981 b. The influence of Patella grazing on the fucoid/barnacle mosaic on moderately exposed rocky shores. Kieler Meeresforschung Sonderheft 5:537-43. Hawkins, S.J. 1983. Interactions of Patella and macroalgae with settling Semibalanus balanoides (L.). Journal of Experimental Marine Biology and Ecology 71 :55-72. Hawkins, SJ. and Hartnoll, R.G. 1983. Grazing of intertidal algae by marine invertebrates. Oceanography and Marine Biology Annual Review 21: 195-282. Hawkins, SJ. and Hartnoll, R.G. 1985. Factors determining the upper limits of intertidal canopy-forming algae. Marine Ecology Progress Series 20:265-71. Hawkins, S.J., Hartnoll, R.G., Kain (Jones), J.M., and Norton, T.A. 1992. Plant-animal interactions on hard substrata in the north-east Atlantic. In Plant-Animal Interactions in the Marine Benthos (ed. D.M. John, S.J. Hawkins and J .H. Price), 1-32. Systematics Association Special Volume No. 46. Oxford: Clarendon Press. Hay, C.H. 1979. Some factors affecting the upper

limit of the southern bull kelp Durvillea antarctica (Chamisso) Hariot on two New Zealand shores. Journal of the Royal Society of New Zealand 9:279-89. HMSO, 1986. The determination of chlorophyll a in aquatic environments, vol. 4. In Methods for the Examination of Water and Associated Materials. Section 2. London: HMSO. Ho, Y.B., 1986. Common intertidal algae of the southren part of Hong Kong Island. Memoirs of the Hong Kong Natural History Society 17:103-6. Hodgkiss, I.J. 1984. Seasonal patterns of intertidal algal distribution in Hong Kong. Asian Marine Biology 1:49-57. Jara, H.F. and Moreno, C.A. 1984. Herbivory and structure in a midlittoral rocky community: a case in southern Chile. Ecology 65:28-38. Jernakoff, P. 1983. Factors affecting the recruitment of algae in a midshore region dominated by barnacles. Journal of Experimental Marine Biology and Ecology 67: 17-31. Jernakoff, P. 1985. Interactions between the limpet Patelloida latistrigata and algae on an intertidal rock platform. Marine Ecology Progress Series 23 :71-8. Johnson, W.S., Gigon, A., Gulmon, S.L. and Mooney, H.A. 1974. Comparative photosynthetic capacities of intertidal algae under exposed and submerged conditions. Ecology 55:450-3. Jones, N .S. 1948. Observations and experiments on the biology of Patella vulgata at Port St. Mary, Isle of Man. Proceedings and Transactions of the Liverpool Biological Society 56:60-77. Kitting, C.L. 1980. Herbivore-plant interactions of individual limpets maintaining a mixed diet of intertidal marine algae. Ecological Monographs 50:527-50. Lewis, J.R. 1964. The Ecology of Rocky Shores. London: English Universities Press. Liu, J .H. 1992. The ecology of Hong Kong limpets. 201 pp. Ph.D thesis, The University of Hong Kong. Lubchenco, J. 1978. Plant species diversity in a marine intertidal algal community: importance of food preference and algal competitive 39

J.H. Liu

abilities. American Naturalist 112:23-39. Lubchenco, J. and Cubit, J. 1980. Heteromorphic life-histories of certain marine algae as adaptations to variations in herbivory. Ecology 61 :676-87. Lubchenco, J. and Gaines, S.D. 1981. A unified approach to marine plant-herbivore interactions. I. populations and communities. Annual Review of Ecology 12:405-37. Morton, B. 1982. An introduction to Hong Kong's hydrographic environment with special reference to the north-eastern New Territories. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 25-53. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Nicotri, M.E. 1977. Grazing effects of four marine intertidal herbivores on the microflora. Ecology 58: 1020-32. Quadir, A., Harrison, P.J. and DeWreede, R.E. 1979. The effects of emergence and submergence on the photosynthesis and respiration of marine macrophytes. Phycologia 18:83-8. Slocum, C.J. 1980. Differential susceptibility to grazers in two phases of an intertidal alga: advantages of heteromorphic generations. Journal of Experimental Marine Biology and Ecology 46:99-110. Southward, A.J. 1964. Limpet grazing and the control of vegetation on rocky shores. In Grazing in intertidal and marine environments (ed. D.J. Crisp), 265-73.

40

Oxford: Blackwell. Steneck, R.S. 1982. A limpet-coralline alga association: adaptations and defenses between a selective herbivore and its prey. Ecology 63:507-22. U nderwood, A.J. 1979. The ecology of intertidal gastropods.Advances in Marine Biology 16:111-210. Underwood, A.J. 1980. The effects of grazing by gastropods and physical factors on the upper limits of distribution of intertidal macroalgae. Oecologia 46:201-13. Underwood, A.J. 1981. Structure of a rocky intertidal community in New South Wales: patterns of vertical distribution and seasonal changes. Journal of Experimental Marine Biology and Ecology 51 :57-85. Underwood, A.J. and Jernakoff, P. 1981. Effects of interactions between algae and grazing gastropods on the structure of a low-shore intertidal algal community. Oecologia 48:221-33. Underwood, A.J. and Jernakoff, P. 1984. The effects of tidal height, wave-exposure, seasonality and rock-pools on grazing and the distribution of intertidal macroalgae in New South Wales. Journal of Experimental Marine Biology and Ecology 75: 71-96. Vadas, R. and Elner, R. 1992. Plant-animal interactions in the north-west Atlantic. In Plant-Animal Interactions in the Marine Benthos (ed. D.M. John, S.J. Hawkins and J.H. Price), 33-60. Systematics Association Special Volume No. 46. Oxford: Clarendon Press.

Asian Marine Biology 10 (1993): 41-44

BIOSYNTHETIC CONDITIONS AND PROPERTIES OF STREPTOMYCES SP. CHITINASE ISOLATED FROM THE MANGROVE RHIZOSPHERE Zheng Zhicheng, l Zhou Meiyingl and Zheng Tianling2 IDepartment of Biology, Xiamen University, Xiamen 361005, China 2Environmental Science Research Centre, Xiamen University, Xiamen 361005, China

Abstract The paper reports upon the biosynthetic conditions and some properties of chitinase produced by Streptomyces sp. isolated from the mangrove rhizosphere. The results show that (NH4 )2 SO 4 and organic nitrogen promote the biosynthesis of chitinase, but carbon sources do not. Higher chitinase production was obtained when Streptomyces sp. was grown in media with either 1.5% steeped corn liquor or 2.0% wheat bran. The optimum culture conditions were: pH 7.0 and between 1.0-1.5 mL inoculum at 30°C for 5 to 6 days. The biosynthesis of chitinase was induced by various forms of chitin, e.g., colloidal chitin, demineralized chitin and deacetyl chitin. Hydrolysis of chitin by chitinase occurred over a broad pH range (3.0-8.5). The optimum pH was 5.5, with better stability within a range of pH 4.0 to 7.5. The enzymatic activity increased with temperature within the temperature range of 30°C to 60°C. The optimum temperature was 60°C. Chitinase activity was 90% at 60°C and exhibits higher temperature stability.

Introduction

Materials and methods

Chitin is the principal structural component of insect and crustacean exoskeletons. The human processing of these shellfish generates a waste disposal problem and chitinase is essential to a bioconversion process in which waste shellfish chitin is enzymatically hydrolyzed to Nacetylglucosamine which, in turn, is assimilated by an edible yeast (Carrod and Tom 1978), and can produce ethanol (Cody et al. 1990). Chitinase may be utilized in biological preparations and in the cell fusion of fungi (Sietsma 1981). This paper describes the biosynthetic conditions and some properties of Streptomyces sp. chitinase isolated from samples of the mangrove rhizosphere.

Test strains of Streptomyces sp. were isolated from samples of the mangrove rizosphere (Zheng et al. 1989). The minimal medium was composed of the following mineral salts (%): 0.07 K 2HPO, 0.05 NaCI, 0.05 MgS0 4 ·7H 2 0 and 0.001 FeS0 4 ·7H 2 0 at pH 7.0. The induced medium was composed of minimal medium plus 2.0% demineralized chitin. Fermentation proceeded in a 500 mL flask containing 50 mL medium inoculated with 1.5 mL spore suspension (1.5 x 107 spores·mL- 1), at 30°C, and shake cultured (240 rpm) for 5 days. The culture supernatants were assayed for chitinolytic activity according to the improved method of hexosamine determination of 10hnson (1971). A

Z.C. Zheng, M.Y. Zhou & T.L. Zheng

unit of chitinase activity is defined as the quantity of the enzyme which releases 1 f..lg Nacetylglucosamine (1 mL sample, 5 mg colloidal chitin, 40°C, 1 h).

Results Effect of carbon-nitrogen sources on chitinase biosynthesis

on the biosynthesis of chitinase were examined in the induced medium. The results indicate that biosynthesis of chitinase is affected by culture conditions. The highest chitinase activity was obtained under conditions of pH 7.0, 30°C, an inoculum size of 1.0-1.5 mL and 5 to 6 days (Figs. I and 2).

Some properties of chitinase

TeSts were undertaken in the induced medium whereby different carbon and nitrogen sources were added. The induced medium served as a control. The results show that (NH 4)2 S04 and organic nitrogen promote biosynthesis of chitinase. The highest chitinase activity (284 u'mL- ' ) was obtained in the induced medium to which had been added 1.5% steeped corn liquor. Carbon sources (starch, glucose, sucrose, maltose, fructose, mannitol) did not promote high chitinase activity (Table I).

The addition of various chitins to the minimal medium (Table 2) suggests that chitinase is an induced enzyme. Colloidal chitin, chitin and demineralized chitin are good inducers, especially at concentrations of 2.0% and 3.0% Table 2. Effects of various chitins on chitinase activity (u·mL-1). Conc. (%)

1.5

Inducers

2.0

3.0 -~----.----~

Effect of culture conditions on the biosynthesis of chitinase The effects of initial pH, amount of inoculum, temperature, amount of aeration and culture time

95 78 75 42

Colloidal chitin Chitin Demineralized chitin Deacetyl chitin Control

190 176 115 76

197 180 161 93 0

Table 1. Effects of carbon-nitrogen sources on chitinase biosynthesis (u·mL-1). Inorganic Nitogen

Organic Nitrogen

Carbon

Conc. (%)

Conc. (%)

Conc. (%) Addition

0.3

0.5

(NH 4)2 S04

166

184

NH 4CI

178

NH 4N0 3 (NH 4)2 C0 3

Control

42

0.5

1.5

2.0

Addition

2.0

Steeped corn liquor

205

284

210

Starch

52

162

Yeast extract

175

164

155

Glucose

20

150

143

Pepton

184

180

160

Sucrose

35

28

36

Bean powder

152

187

177

Fructose

43

Wheat bran

163

196

202

Maltose

35

Mannitol

16

Addition

150

Chitinase of Streptomyces

The effects of pH on chitinase activity and the stability of chitin hydrolysis were examined in mixtures of 1 mL enzyme and 1 mL citrate-buffer (0.1 M at various pH values) containing 5 mg

colloidal chitin, incubated at 40°C for 1 h. The hydrolysis of chitin occurred over a pH range of 3.0 to 8.5, with best stability within a pH range of 4.0 to 7.5, and an optimum of pH 5.5 (Fig. 3).

150

150

/ - 7 - ' - ............ '

/

/ :::;-100

~

6 28 1.0

7 30 1.5

8 32 2.0

9 34 2.5

Fig. 1. Effects of initial pH, amount of inoculum and temperature on the biosynthesis of chitinase.

day

.q

~

10 60

-

ee_

I

~ Q::;

I I I

> 60

.~

Q)

.~ 40 ~ Q::;

20 0

3456789 pH

Fig. 3. Effects of pH on chitinase activity and stability. Enzyme activity Enzyme stability

80

.q

I I

>

20

'\

8 50

6 10

Amount of aeration (mL) Time (days)

I I

60

Q)

\

100

80

~ 40

\

Fig. 2. Effects of culture time and amount of aeration on the biosynthesis of chitinase.

100

.j

4 30

2 20

ml

Initial pH Temperature (QC) Amount of inoculum (mL) ........ .

~

I'

I'

-

, , --~' . O....::;;;;..&...----L.--L_&...-.....L.----L._L..-...L..-........---L._

O'--~~~"""&----"'---''--~....I.-~--'---'

5 26 0.5

\, \

,

I'

pH 4 °C 24 ml 0

,

/ i i

Fig. 4

I

30

40

50 °C

60

70

Effects of temperature on chitinase activity and stability. Enzyme activity Enzyme stabiity 43

Z.C. Zheng, M.Y. Zhou & T.L. Zheng

The effects of temperature on chitinase activity and stability of chitin hydrolysis were also examined in mixtures of 1 mL enzyme and 1 mL citrate-buffer (0.1 M, pH 5.0) containing 5 mg of colloidal chitin, incubated at various temperatures for 1 h. The results show that the enzymatic activity of chitin hydrolysis increased with temperature, within a range of 30°C to 60°C. The highest activity occurred at 60°C. Chitinase stability was maintained within a temperature range of 30°C to 60°C and 90% activity was retained at 60°C. The activity declines rapidly at temperatures > 60°C (Fig. 4). A reason for the decline may be deactivation of chitinase at higher temperatures.

Discussion Sources of chitin are abundant in nature. Chitins are structural components of crustaceans, insects, fungi, protozoa and nematodes. Chitin is an unbranched polysaccharide composed primarily of B-l,4 linked N-acetylglucosamine residues with occasional glucosamine residues (Brimacombe and Webber 1964), is highly resistant to organic solvents and requires strong mineral acids for solubilization. Microbial organisms producing chitinase include bacteria (Cody 1989), molds,

yeasts (Cody et al. 1990) and actinomycetes (Hsu and Lockwood 1975). Microbial chitinase is important in the conversion of waste chitin to Nacetylglucosamine which, in turn, is assimilated by other micro-organisms to produce some fermentation products such as edible yeast and ethanol. Microbial chitinase thus has a broad application and could be developed. Marine Streptomyces sp. is able to produce more chitinase (150 u'mL-') in a medium containing chitin used as a sole carbon source, e.g., 2.0% demineralized chitin. The highest chitinase activity (284 u'mL-') was obtained under the specified conditions of 1.5% steeped corn liquor, pH 7.0 at 30°C for 5 days. The enzymatic activity of chitinase has a wide range and a better pH stability. The optimum temperature for enzymatic action and stability of the chitinase is high. The results presented in this paper offer information for the further study, development and application of microbial chitinase.

Acknowledgements The authors wish to thank Prof. Brian Morton and an anonymous referee for their critical reading of the first draft of this paper.

References Brimacombe, J.S. and Webber, J.M. 1964. Mucopolysaccharides: Chemical Structure, Distribution and Isolation, vol. 6, 18-42. New York: Elsevier. Cody, R.M. 1989. Distribution of chitinase and chitobiase in bacillus. Current Microbiology 12:201-5. Cody, R.M., Davis, N.D., Lin, J. and Shaw, D. 1990. Screening microorganisms for chitin hydrolysis and production of ethanol from amino sugars. Biomass 4:285-95. Carrod, P.A. and Tom, R.A. 1978. Bioconversion of shellfish chitin wastes: process conception and selection of microorganisms. Journal of Food Science 43: 1158-61. Hsu, S.C. and Lockwood, J.L. 1975. Powdered 44

chitin agar as a selective medium for enumeration of actinomycetes in water and soil. Applied Microbiology 3:422-6. J ohnson, A.R. 1971. Improved method of hexosamine determination. Analytical Biochemistry 44:628-35. Sietsma, J.H. 1981. Solubility of (I - 7 3)-B-DI (I - 7 6)-B-D-glucan in fungal walls: importance of the presumed linkage between glucan and chitin. The Journal of General Microbiology 125:209. Zheng, Z.C., Zhou, M.Y. and Yao, B.X. 1989. Composition and biological activity of actinomycetes in mangrove rhizosphere. Journal of Xiamen University (Natural Science) 3:306-10.

Asian Marine Biology 10 (1993): 45-53

MARINE ENCLOSURE ECOSYSTEM EXPERIMENTS TO STUDY RED TIDE MECHANISMS AND PROCESSES IN XIAMEN HARBOUR, CHINA * Lin Yu, Zhuang Dongfa, Tang Senming, Chen Xiaolin Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China

Abstract Marine enclosure ecosystem experiments have been conducted in a land-based tank at the Third Institute of Oceanography by the Marine Experimental Enclosure Research Centre (MEERC) to understand red tide stimulating mechanisms. Three experiments on an artificially induced red tide are discussed in this paper. It demonstrates the relationships between the occurrence and scale of red tides and environmental conditions, interspecific reactions and succession. As the results obtained are similar to natural red tide processes observed in western Xi amen Harbour, it is clear that the experiment offers a means of controlling and forecasting red tides in this area.

Introduction The sea is a huge integrated ecosystem of water, sediments and biological components, among which material and energy transference is continuously going on due to water movements. Thus, each specific ecosystem in the sea is maintaining its balance by regular and variable changes. Simultaneous transient water movements make investigation of the sea so much more difficult while ecological results obtained in the laboratory cannot be simply extrapolated to the natural system due to the multidimensional interrelationships of the environment. Marine enclosure ecosystem experiment (MEEE) technology, characterized by its multidisciplinary nature, has been developed over the last three decades. In this controlled enclosure ecosystem, the assessment and study of a marine ecosystem can be conducted in terms of the dynamics of biological succession, energy transference, physical-chemical variations and the timing of biophysiological activities. The system has bridged the gap between flask and sea where difficulties remain in investigation both in the

laboratory and the field (Grice and Reeve 1982; Wu et al. 1988; Lalli 1990). From 1983 to 1986, with the financial aid of The State Oceanographic Administration of China and The International Development Research Centre of Canada, the co-operative Marine enclosure ecosystem experiment by Canada and China has been successfully realized through the efforts of scientists and an international symposium held in Beijing in 1987 to summarise the work. As a result, an experimental base for marine enclosure ecosystem experiments in China was set up by the Marine Experimental Enclosure Research Centre, The State Oceanographic Administration of China. Since 1984, the Marine Experimental Enclosure Research Centre has conducted several experiments in which a total of 51 enclosures were employed to study the effects and fate of pollutants, for example, heavy metals, oil and dispersants (Tang et al. 1990; Zhuang and Lin 1991; Wong and Harrison 1992). Since the spring of 1990, experiments using marine enclosure ecosystem experiment techniques have been conducted to investigate red tides caused by eutrophication.

* This paper was presented at a colloqium on red tides in Hong Kong and South China convened in Hong Kong from 9-11 September 1992.

Y. Lin, D.F. Zhuang, S.M. Tang & X.L. Chen

In these experiments, the interrelationships between some important nutrients, such as N, P, Mn, Fe and B 12' to red tide occurrence and scale, and the general rules of the interactions between the occurrences and species has been studied. Here, the results of three (experiment RI' R2 and R 3 ) out of four experiments are discussed.

Materials and methods The enclosures

Woven polypropylene bags, lined with a layer of polyethylene to prevent water mixing, were used in experiment RI' About 7.5 m 3 of the water column was enclosed in each bag (Fig. lA). The enclosures used in the experiment R2 were fibreglass barrels with volumes of 1.5 m 3 and lined with a layer of polyethylene (Fig. 1B). In addition to the enclosures for the mesocosms experiment, a microcosms experiment, using 60-L polyethylene barrels, was conducted. Facilities and methods

The experiments were carried out in a land-based tank, of 20 x 10 x 5 m 3 , at the Third Institute of Oceanography. The enclosures were fixed to a steel frame and floated in the middle of a larger tank (Fig. lA). The barrels were made to stand in the tank. Before the experiment, nearshore water

was pumped in and distributed simultaneously into the enclosures through a manifold. The big tank was kept at a given depth of water and sea temperature maintained by pumping in fresh seawater every day. This also made up water loss due to tank leakage. The RI experiment was conducted during May and July 1990. Three phases made up the experiment. In the first phase (0-22 days) observations were made to compare variations in phytoplankton biomass under eutrophic and oligotrophic conditions. Bag Cl was set up as the control in which the concentrations of nutrients were monitored with time and compensated for to maintain nutrient levels similar to those in the sea. Bag HI had excess nutrients added and maintained at levels of 30, 20 and 3 JlIllol·L- 1 for nitrate, silicate and phosphate, respectively, by adding nutrients whenever values fell. For bag L I, the concentration of phosphate was maintained low to mimic nutrient levels in the seawater of Western Xiamen Harbour after a spring bloom, while the concentrations of nitrate and phosphate were kept at 15 and 0.2 JlIllol·L-I, respectively. The observations made in the second phase (23-62 days) were to follow phytoplankton dynamics under conditions of high nutrient level and when nutrient levels are transformed from an oligotrophic to a eutrophic state by raising the concentrations of nutrients in bag Cl and LI to the level in bag HI' The addition of nutrients was

-4mt Bag

A Fig. 1.

46

B

The design of the enclosure experiment. A, enclosure bag; 8 , experimental tank and fibreglass barrel.

Red tides in Xiamen Harbour

halted in the third phase (63-76 days) when the released nutrients from the sediments are supposed to support algal growth. The R2 experiment was carried out in the spring of 1991. The nutrients in each barrel were kept at the level of 50 and 3 }JlIlol·L-1 for nitrate and phosphate, respectively. At the same time, concentrations of 0, 25, 50 and 100 Ilg·L-I of soluble manganese were added to barrels C 2, L 2, M2 and H 2, respectively. A microcosm experiment (R3) repeated the R2 experiment in the autumn of 1991. The added water was aged in order to induce algal blooms other than diatoms. Except for C 3 , which was used as a control with no manganese added, all barrels were contaminated with manganese at concentrations above 1.4 mg· L- I. The analytical methods used in the experiments are described by Lin et al. (1992a, b, 1993).

phytoplankton biomass occurred in the phosphate limited bag, L I. However, diatoms bloomed in bag LI when excessive nutrients were added. Dinoflagellates and chrysophytes dominated blooms which were observed in all the bags after 45 days (Fig. 2). In experiment R 2 , the diatom, Skeletonema costatum , formed a bloom four days after the start of the experiment and the numbers of cells reached 3.0, 2.6, 2.7 and 3.0 x 107-L- I in bags C 2, L 2, M2 and H 2, respectively (Fig. 3). During the R3 experiment, an Oscillatoria bloom occurred during which the peak in cell density was 6.1 x 107·L-I, three times that of bag L3 (Fig. 3). The effects of environmental conditions on algal blooms Water column stability. The differences between the enclosed water columns, where the red tide or algal bloom had been induced and the seawater in the vicinity, were that the enclosed water was rather stable compared with the natural water which is always disturbed by tidal currents

Results In experiment RI' an algal bloom was induced in bag HI in the first phase while little change in

50.0

......

CBag

~

LBag

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as I

0

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10.0

o 4

9

14

21

27

34

41

48

55

62

69

76 (d)

Fig. 2. Changes in chlorophyll-a values in the enclosure bags during the R1 experiment. 47

Y. Lin, D.F. Zhuang, S.M. Tang & X.L. Chen

----

C2 0---0 L2 A-·A M2 A--ll. H2

8

7

-

... '

6

.

...~./

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./ ./

~ 0

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o 1 34

6

8

11

14

17

20

(d)

Days Fig. 3. Changes in algal cell density during the R2 and R3 experiments.

and waves. The area where red tides occur frequently are inside Baozhuyu Bay in western Xiamen Harbour, where the sea is calm and water exchange weak. The similarity of the water conditions here to the enclosed water column may be one important factor influencing red tide occurrences (Zhang et al. 1989; Lin et al. 1992a).

especially active phosphate, in western Xiamen Harbour, have a close relationship with the occurrence and developments of red tides in this area. This is also indicated by the results of a closed observation on red tides in the area in 1986 and 1987 (Chen 1987; Zhang et al. 1989; Lin et al. 1992a).

The relationships between nutrient level and red tide occurrence

The relationship between dissolved manganese and red tides

The three experiments showed that eutrophication of the enclosed water column always led to either algal blooms or red tides, if certain physical factors were met. Investigations in western Xiamen Harbour demonstrated that nutrient levels of the area are in a mesotrophic state. It could be, therefore, that basic conditions for a red tide occurrence in the enclosed water column are met when nutrients are added. In comparison, bag Ll did not bloom in the first phase at low phosphate concentrations. It did, however, when sufficient nutrients were supplied. This shows that the concentrations of nutrients,

Figures 4 and 5 show that, though different concentrations of dissolved manganese were added, variations in phytoplankton numbers and structure were almost the same. This suggests that dissolved manganese at a level of 3-4 Ilg·L-l, as in barrel C 2 , is sufficient for the multiplication of algae and red tide occurrences. The excessive dissolved manganese at levels < 80 Ilg·L-1 in seawater would make no difference to phytoplanktonic biomass and community structure. The situation changed, however, when the concentration reached lA mg·L-l, as in barrel L3 where the structure of the phytoplankton

48

Red tides in Xiamen Harbour

~ 1.3° c:

~

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>

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Fig. 4. Changes in the concentrations of dissolved manganese in the R2 and R3 experiments.

100

100

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80

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60

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40

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0 0

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Days

Fig. 5. The percentage changes in the importance of phytoplankton groups in the R2 experiment. (0 - diatoms, • - dinoflagellates, ~ - microflagellates, ® -

Cryptophyta).

49

Y. Lin, D.F. Zhuang, S.M. Tang & X.L. Chen 100~-------------------,

100 - - - - - - - - - - -.......

80

80

60

60 40

20

20

o1

3 4 6 8 11 Days

14

17 20

o1

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8 11 Days

14

17 20

Fig. 6. The percentage changes in the importance of phytoplankton groups in the R3 experiment. (€l - microflagellates, @ - Cryptophyta. 0 - Cyanophyta.)

community varied and numerical development was confined to a certain extent, in comparison with C 3 (Lin et al. 1993). Interspecijic reactions and red tides Phytoplankton succession. As sufficient nutrients were kept in bag HI' algae bloomed in the

following sequence: diatoms (dominated by Navicula and Nitzchia), dinoflagellates and Chrysophyta. Figure 7 shows the changes in numbers of dinoflagellates and diatoms. The numerical changes seem to show species exclusion, since no dinoflagellates were observable when diatoms bloomed after 11 to 18 days. Dinoflagellates increased to high numbers

8

~

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12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 Days

Fig. 7. The temporal distribution of diatoms (e (... - ... ) in bag Hl of the Rl experiment. 50

e), dinoflagellates (0- 0) and microflagellates

Red tides in Xiamen Harbour

with the decline of the diatoms until day 45, when few diatoms were detected. After 55 days, diatoms recovered in numbers and dinoflagellates disappeared again at day 69. It is clear from Table 1, that more centric diatom species occurred in the first 10 days; most species of pennate diatoms occurred from 11 to 23 days, disappeared after 47 days and reappeared later. More dinoflagellate species appeared later in the experiment. In view of either the numbers of diatoms and dinoflagellates or the species diversity of both in each phase of the experiment, algal blooms induced by eutrophication in the enclosed water column first occurred in diatoms and then dinoflagellates and microflagellates (~ 20 Jlm). The species and numbers of dinoflagellates always dominated in the later part of the experiment. This phenomenon was repeated in the R2 and R3 experiments. Davis (1982) has commented on the results of Foodweb I experiment, in which phytoplankton succession was similar to our experiments. In general, such succession may not occur in Xiamen Harbour, but this is not contradictory with the results of our experiments. Our experiments

only showed that phytoplankton succession during a red tide proceeds under a eutrophic state. (Lin etal.1992b) It is interesting that the experimental sequence was rather similar to the process of red tide occurrences in western Xiamen Harbour in 1986. The first unusual bloom was dominated by Dactyliosolen mediterraneus for one week. Ten days later Gymnodinium sp. took this position and formed a larger scale dinoflagellate red tide (Du 1988). It can be considered that experiment RI successfully simulated red tide algal succession, which is induced by nutrient enrichment from the seawater of western Xiamen Harbour. It demonstrated the processes of red tide occurrence. The experiment has its practical significance in that the data obtained can be used to forecast possible red tide occurrences in this area. Grazing pressure. These experiments demonstrated that in many mesocosm experiments, zooplankton populations were variously sensitive to pollutant stress which, in turn, led to alterations in ecosystem structure. In this case, the development of phytoplankton populations was

Table 1. The appearance time of various phytoplankton species in bag H1 of the R1 experiment. Appearence time (days)

Ske/etonema costatum Tha/assiosira subtilis Chaetoceros spp. Rhizosolenia sp. Amphora costata Navicula spp. Nitzschia spp. Pleurosigma sp. Amphora ostrearica Dip/oneis bombus Fragilaria sp. Ceratium sp. Gymnodinium sp. Periodinium sp. Exuviaella sp. Prorocentrum micans Chrysophyta microflagellates

(~

20 Jlm)

1-10

+ + + + + + + +

11-20

21-23

24-47

+ + + + + + +

+ + +

+ + +

+

48-58

+

+ +

69-76

+

+ + +

+ + + + + +

+

+

+

+ + + +

+ +

+ +

+ +

+ + +

59-68

+

+ + 51

Y. lin, D.F. Zhuang, S.M. Tang & X.L. Ch en

closely correlated with the zooplankton community and individual numbers (Parsons et al. 1984; Chen et al. 1988; Tang 1992).

Discussion Though these preliminary results can only demonstrate some mechanisms of red tide occurrence at the community level, to understand the whole mechanism will need much more research. The relationships between such factors as Fe, B 12 and organic matter to red tide occurrence and scale, disturbance to the water column and interference with phytoplankton succession by the rate of supply of nutrients, all need to be investigated. Results and data from these types of experiments are necessary for red tide forecasting and control. As the water columns enclosed were typical of western Xiamen Harbour characterized by mesotrophication, some physical and chemical conditions, such as the concentration of dissolved manganese, have already met the requirement for an algal bloom. It is difficult to obtain a

quantitative relationship between environmental factors and algal biomass. What could be done is to analyse ecological effects resulting from changes in these factors. In conclusion, the experiments are limited by the conditions of the experimental seawater. In addition, the materials and energy exchange between sediments and the water column are important links in the process of red tide occurrence. We are examining the possibility of conducting enclosure experiments that combine the pelagic and benthic ecosystems. It is believed that such a system is indispensable to the study of red tide mechanisms.

Acknowledgements The authors gratefully acknowledge the National Science Foundation of China for funding project No. 9389008. Special thanks are due to Prof. Brian Morton for his critical reading of the first draft of the manuscript of this paper. We also thank an anonymous referee for his corrections and suggestions.

References Chen, X.L., Lin, J.M. and Lalli, C.M. 1988. The effects of heavy metals and sediments on zooplankton in a experimental marine ecosystem. Acta Oceanologica Sinica 4:6301. Chen, Y.W. 1987. Analysis the trophic condition of Xiamen Harbour. Marine Environmental Science 3: 15-9. (In Chinese) Davis C.O. 1982. The importance of understanding phytoplankton life strategies in the design of enclosure experiments. In Marine Mesocosms (ed. G.D. Grice and M.R. Reeve), 323-33. New York: Springer-Ver1ag. Du, Q. 1989. Investigations on red tide in the west area of Xiamen sea. Journal of Jinan University (monograph of study on red tides), 57-67. Grice, G.D. and Reeve, M.R. 1982. Marine Mesocosms. New York: Springer-Verlag.

52

Lalli, C.M. 1990. Enclosed Experimental Marine Ecosystems: A Review and Recommendations. New York: Springer-Verlag. Lin, Y., Chen, X.L., Zhuang, D.F., Tang, S.M. and Lin, R.C. 1992a. Preliminary study on red tide caused by nutrient enrichment in marine enclosed ecosystem. Oceanologia et Limnologia Sinica 3:312-7. Lin, Y., Chen, X.L., Zhuang, D.F., Wu, S.S., Cai, Z.P., Tang, S.M. and Lin, R.C. 1992b. Primary analysis on the phytoplankton community structure of red tide processes in marine enclosed ecosystem. Acta Ecologica Sinica 3:213-8. Lin, Y., Tang, S.M., Chen, X.L. and Zhuang, D.F. 1993. The effects of dissolved Mn on the multiplications of two red tide algae in the enclosure ecosystem. Acta Oceanoiogica Sinica 4:91-8.

Red tides in Xi amen Harbour

Parsons, T.R., Harrison, P.I., Acreman, I.C., Dovey, H.M., Thompson, P.A., Lalli, C.M., Lee, K., Li, G.G. and Chen, X.L. 1984. An experimental marine ecosystem reponse to crude oil and Corexit 9527: part 11biological effects. Marine Environmental Research 13:265-75. Tang, S.M., Chen, X.L. and Zhuang, D.F. 1990. Marine ecosystem enclosure experiment and environment protection. In The Third International Conference of Specialists in Marine Fishery-East China Sea Symposium, 1990, 80-4. Tokyo. Tang, S.M. 1992. The effect of BP-II00X dispersant and dispersed crude oil on the phytoplankton populations in MEE. Acta Oceanologica Sinica 2: 130-4.

Wong, C.S. and Harrison, P.I. 1992. Marine ecosystem enclosed experiments. Proceedings of a Symposium held in Beijing, China. Ottawa: International Development Research Centre. Wu, I.P., Chen X.L., Zhuang D.F. and Wu S.S. 1988. Progress in marine ecosystem enclosure experiments. Advances in Ecology 1:43-50. Zhuang, D.F. and Lin, Y. 1991. The effects of nutrients and heavy metals on the plankton in marine enclosed ecosystems. Acta Oceanologica Sinica 4:637-40. Zhang, S.I., Xu, K.C., Chen, Q.H. and Zeng, Z.W. 1989. Observation of a red tide event in the western harbour, Xiamen. Acta Oceanologica Sinica 3 :464-6.

53

Asian Marine Biology 10 (1993): 55-75

SOME CORAL REEF PONTONIINE SHRIMPS FROM VIETNAM

A.J. Bruce Division of Natural Sciences, Northern Territory Museum, P.O. Box 4646, Darwin 0801, Australia

Abstract Records are provided of 25 species of pontoniine shrimps from the coral reefs of Vietnam. Few carideans have been previously reported from Vietnamese seas and all species, except Anchistus miersi De Man, Coralliocaris graminea and Periclimenes brevicarpalis (Schenkel), are now recorded there for the first time, although most are common and well-known Indo-West Pacific species. Most of the species reported are commensals of corals or bivalve molluscs. Many more species associated with other types of host, or free-living, may be expected to occur in Vietnamese waters. The fauna of Vietnam is compared with those of Hong Kong and Singapore.

Introduction The shrimp fauna of Vietnam has attracted very little scientific attention, and few pontoniine shrimps from that country have been reported in the scientific literature. The only citations located are those of Kemp (1922), who reported the occurrence of Anchistus miersi (De Man), Coralliocaris graminea (Dana), and Periclimenes brevicarpalis (Schenkel), all from Pulo Con Dua (Pulo Condore). The pontoniine faunas of both Singapore and Hong Kong are comparatively well known, having been initiated by the studies of Lanchester (1900) and Stimpson (1860), respectively and augmented considerably in more recent times (John son 1961, 1979; Bruce 1979, 1982, 1990a, 1992). Almost 60 species are known collectively from the three regions, but less than half have been collected from any single locality. Both Hong Kong and Singapore represent restricted sites and habitats that have now been long subjected to intense human interference. Their present faunas may well represent their actual and probably diminishing fauna, but the long coastline of Vietnam may be expected to provide a much great diversity in due course when studied in more detail. The present collection was made by Dr T.A. Britaev and Dr Y.Y. Dgebuadze by snorkel and

SCUBA in 1985-87, supported by the Institute of Evolutionary Animal Morphology and Evolution, Moscow, and Marine Research Institute of Vietnam, Nha Trang, and 1989-90, by the SovietVietnamese Tropical Research Centre, and consists primarily of species from branching coral hosts and bivalve molluscs. The collections were made mainly at Tarn, Tre and Mung Islands, off Nha Trang. The specimens reported upon are deposited in the collections of the Northern Territory Museum, Darwin. A parallel collection has been placed in the collection of the Zoological Collection, Moscow State University. Restricted synonymies only are provided, with fuller details being available in Holthuis (1952). Carapace length (CL) refers to the postorbital carapace length.

Systematic Account

Anchistus australis Bruce Anchistus australis Bruce, 1977: 56-62, figs 7-9. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. 19, 3 rn, 7 March 1990, NTM Cr.008374.

A.J. Bruce

Fig. 1. Map of localities mentioned in text; inset, approximate position of localities in the South China Sea.

Remarks. The female has a rostral dentition of 4/ I, the male has a dention that may be interpreted as 5/0 or 4/1. Host. Tridacna squamosa Lamarck [Mollusca: Tridacnidae] . Distribution. Type locality: Capre Cay, Swain Reefs, Great Barrier Reef. Also known from Indonesia, northern Australia, New Caledonia, Fiji and the Marshall Islands. 56

Anchistus custoides Bruce Anchistus custoides Bruce, 1977: 50-56 figs. 46. Material examined. (i) 1 juv., Tre Island, stn 2, 7 m, 14 February 1987, NTM Cr.008375. Remarks. The single example has a carapace length of 2.5 mm, and lacks both second pereiopods, with a single attached first pereiopod

Pontoniine shrimps from Vietnam

and a detached ambulatory pereiopod. The rostrum has three minute denticles distodorsally and the first pereiopod chela has non-cannulate fingers and palm.

24 December 1988, NTM Cr.008380. (ii) 1 ovig. female, Tarn Island, stn. 12, 6 January 1989, NTM Cr.008381. Remarks. The specimens agree closely with previous descriptions.

Host. Pinna sp., [Mollusca: Pinnidae]. Distribution. Type locality: Gillet Cay, Swain Reefs, Great Barrier Reef. Also known from the Ryukyu Islands, Japan; One Tree and Heron Islands, Capricorn Islands, Great Barrier Reef and Seram Island, Indonesia. Anchistus custos Forsskal Cancer custos Forsskal, 1775: 94. Harpilius inermis Miers, 1884: 291, pI. 32 B. Anchistus inermis - Borradaile, 1898:387. Anchistus custos - Holthuis, 1952: 105-109, figs. 86-89. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. 2, 2 m, 13 February 1987, NTM Cr.008378. (ii) 1 male, 1 ovig. female, Tarn Island, stn. 5, 2 m, 20 February 1987, NTM Cr.008376. (iii) 2 juv., Tre Island, stn. 6, 2-4 m, 25 February 1987, NTM Cr.008377. (iv) 1 male, 1 ovig. female, Tre Island, stn. 13,26 March 1990, NTM Cr.008379. (v) 1 male, 1 ovig. female, idem, NTM Cr.008484. Remarks. The specimens are typical of this wellknown, common and widely-distributed species. Host. All specimens were found in association with Pinna sp. or Pinna bicolor Chemnitz [Mollusca: Pinnidae]. Distribution. Type locality: AI-Luhayyah, Yemen. Otherwise recorded from the Red Sea to Mozambique, Japan to South Australia, east to Palau, Caroline Islands and the Fijian Islands. Anchistus demani Kemp Anchistus demani Kemp, 1922: 256-259,figs. 8689. Material examined. (i) 1 male, Tre Island, stn. 12,

Host. Tridacna maxima Lamarck [Mollusca: Tridacnidae] . Distribution. Type locality: Port Blair, Andaman Islands. Also reported from Kenya, Zanzibar, Madagascar, Comoro Islands, Seychelle Islands, Malaysia, Indonesia, Thailand, Great Barrier Reef and New Caledonia. Anchistus miersi De Man (Fig. 3A) Harpilius miersi De Man, 1888: 274, pI. 17, figs. 6-10. Anchistus miersi - Borradaile, 1898: 387. Material examined. (i) 1 male, I ovig. female, Tre Island, stn. 7, 1.5-2 m, 29 November 1985, NTM Cr.008382. (ii) 2 juv., Tre Island, stn. 12, 24 December 1988, NTM Cr.008383. (iii) 1 male, idem, NTM Cr.008384. (iv) I male, Tre Island, stn. 12, 5 January 1989, NTM Cr.008385. (v) 1 male, 1 ovig female, idem, NTM Cr.008386. (vi) 1 male, 1 ovig. female, idem, NTM Cr.008387. (vii) 1 male, 1 ovig. female, Tre Island, stn. 15, 11 January 1989, NTM Cr.008388. (viii) 1 ovig. female, Tarn Island, stn. 4, 9 February 1989, NTM Cr.008389. (ix) 1 ovig. female, Tarn Island, stn. 4,10 February 1989, NTM Cr.008391. (x) 1 male, idem, NTM Cr.008392. (xi) 1 male, idem, NTM Cr.008393. (xii) 1 male, 1 ovig. female, Rua Island, stn. 1, 16 February 1989, NTM Cr.008394. (xii) 1 male, 1 ovig. female, Mui Nam, Tre Island, 3 m, 28 February 1990, NTM Cr.008395. (xiv), 1 male, 1 ovig. female, Tre Island, stn. 19, 3 m, 7 March 1990, NTM Cr.008411. (xv) 1 ovig. female, Tre Island, stn. 4, 9 March 1990, NTM Cr.008412. (xvi) 1 ovig. female, Cape Hoi, Cam Ranh Bay, 12 March 1990, NTM Cr.008413. (xvii) 1 male, 1 ovig. female, Tre Island, stn. 12, 19 March 1990, NTM Cr.008414. (xviii) 1 male, 1 ovig. female, Tre Island, stn. 20, 3 m, 28 March 1990, NTM Cr.008415.

57

A.J. Bruce

2.0 mm F

F

D 13.0 mm CD

10.5 mm B

I

I

B Fig. 2. Coralliocaris superba (Dana). A, carapace and rostrum, male. B, same, female. Coralliocaris venusta Kemp. C, carapace and rostrum, ovigerous female. D, E, same, juvenile females. Coralliocaris viridis Bruce. F, carapace and rostrum, ovigerous female. Harpiliopsis beaupresii (Audouin). G, anterior carapace and rostrum, male.

Remarks. The specimens agree with the data provided by Kemp (1922) and Holthuis (1952). All specimens show the lateral posterior telson spines (Fig. 3A) in a subdorsal position as illustrated by Holthuis (1952, fig. 45). Kemp does not precisely describe the condition in his material, from the Mergui Archipelago, Pulo Con Dua and Jakarta. The posterior telson spines are identical in specimens from Tridacna maxima and T. squamosa. 58

Host. Specimens were collected from Tridacna maxima Lamarck. (v) (ix) (x) (xvii); T. squamosa, Lamarck (ii) (iii) (iv) (vi) (vii) (viii) (xi) (xii) (xiv) (xv) (xvi) (xviii); and Tridacna sp, (i). [Mollusca: Tridacnidae] . Distribution. Type locality: Elphinstone Island, Mergui Archipelago, Burma. First recorded from Vietnam, at Pulo Con Dau, by Kemp (1922). Also known from Kenya, Zanzibar, Tanganyika,

Pontoniine shrimps from Vietnam

D

c 1.0 mm

c

0.3 mm AEHKL

G , 1.0 mm

B

,O.S mm, F

0.5 mm DI

Fig. 3. Anchistus miersi (De Man). A, posterior telson spines, ovigerous female. Coralliocaris superba (Dana). B, rostrum, female. C, third maxilliped, male, dorsal. D, same, distal segment of endopod. E, posterior telson spines, female. F, fourth thoracic sternite, female. Coralliocaris venusta Kemp. G, third maxilliped, ovigerous female, dorsal. H, same, distal segment of endopod. Coralliocaris viridis Bruce. I, same. Harpiliopsis beaupresii (Audouin). J, third maxilliped, male, ventral. K, third pereiopod, distal propod and dactyl, lateral. L, same, medial.

59

A.J. Bruce

Madagascar, Comoro, Seychelle, Chagos, Maldive and Andaman Islands, Malaya, Singapore, South China Sea, Philippines, Indonesia, Australia, Papua New Guinea, New Caledonia, Ryukyu, Caroline and Marshall Islands; and Tuvalu. Records of specimens from non-tridacnid bivalve hosts, such as Pteria or Pinna spp. require confirmation. Conchodytes kempi Bruce (Fig. 4) Conchodytes biunguiculatus - Kemp, 1922: 280282, fig. 103. Conchodytes kempi Bruce, 1989: 183-184, fig. 3 b-e.

B

Material examined. (i) male, 1 ovig. female, Tre Island, stn. 13, 26 March 1990. NTM Cr.008416. Remarks. The single pair of specimens are distinctly larger than the following species, (CL male 9.4, ovig. female 11.2 mms), and agree with previous descriptions of specimens reported in the literature from the same host. The ambulatory dactyls have a well developed distal accessory tooth and a compressed basal protuberance with a distinctly acute tooth (Fig. 4B). The lateral posterior telson spines (Fig. 4C and D) are not markedly subdorsal and preterminal as in C. biunguiculatus (Paulson), but could be described as very feebly subdorsal and preterminal. The exopod of the uropod bears a small mobile

0.2 mm B

0.2 mm E

A

0.5 mm

CD 1.0 mm

A

E

Fig. 4. Conchodytes kempi Bruce, ovigerous female. A, paragnaths. B, distal propod and dactyl of ambulatory pereiopod. C, posterior telson spines, female. D, same, male. F, exopod of uropod, posterolateral angle.

60

Pontoniine shrimps from Vietnam

spinule, but is without a distinct fixed tooth (Fig. 4E).

The specimens differ in a number of minor features from the specimens provisionally referred to this species, found in association with Isognomon in the Philippines (Bruce 1989), particularly in their much larger size, but also in the better development of the basal protuberance of the ambulatory dactyls and in the posterior telson spines. In the present specimens, the submedian spines are separated by a small interval, not arising contiguously, from a rounded posterior margin, not from a small projection of the posterior margin, with the spines shorter than, not exceeding, the intermediate spines. The lateral spines are very robust, about half the length of the intermediate dorsal spines, and, as mentioned above, feebly preterminal and subdorsal in position, rather than marginal. These differences suggest than the specimens from Isognomon may represent a distinct taxon, but the examination of further material from this host is necessary before this can be confirmed. The mouthparts of this species have been described by Holthuis (1952) and HipeauJacquotte (1973), (as c. biunguiculatus), but these authors did not describe the paragnaths. These are well developed, with large, feebly bilobed nonspinulate alae (Fig. 4A). The corpus is elongate with a pair of oval submedian eminences anteriorly, with feebly carinate lateral margins, and the median posterior part broadly cannulate, with setose lateral borders. The morphology of the paragnaths in C. kempi shows some remblance to the condition shown in Pontonia pinnophylax (Otto), in which the median part of the corpus is deeply channelled with sharp, setose lateral margins (Bruce 1991), and further emphasizes the close relationship between Conchodytes and Pontonia. Host. Pinna bicolor Cheminitz [Mollusca: Pinnidae]. Distribution. Type locality: Andaman Islands. Also known from the Red Sea, Kenya, Zanzibar, Madagascar, Seychelle Islands, Indonesia, Taiwan, Marshall Islands, and possibly the Philippines.

Conchodytes meleagrinae Peters Conchodytes meleagrinae Peters, 1852:25. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. ?, 2-4 m, 13 February 1987, NTM Cr.008417. (ii) 1 male, 1 ovig. female, Tre Island, stn. 2, 1.5-4m 13, February 1987, NTM Cr.008418. (iii) 1 male, 1 ovig. female, Tarn Island, stn. 4, 10 February 1989, NTM. Cr.008419. (iv) 1 male, 1 ovig. female, Nam Island, Cam Ranh Bay, 2 m, 13 March 1990, NTM Cr.008420. (v) 1 male, 1 ovig. female, Tre Island, stn. 10, 8 m, 27 March 1990, NTM Cr.008421. (vi) 1 male, 1 female, Tre Island, stn. 10, 6 m, 27 March 1990, NTM Cr.008422. Remarks. The specimens present no special features. In the first pereiopods, the carpus is shorter than the merus. Typical carapace lengths for these specimens are: male, 4.0; female, 5.0 mms. Hosts. (i), (ii), (iii), Pinctada sp.; (iv), Pinctada margaritifera (L.); (v), and (vi), Pinctada nigra Chemnitz [Mollusca: Pteriidae]. Distribution. Type locality: Ibo, Mozambique. Otherwise recorded extensively from the Red Sea to Mozambique, Japan to the Great Barrier Reef, east to Hawaii. Corallicocaris superba (Dana) (Figs. 2AB, 3B-F) Oedipus superbus Dana, 1852:25; 1852a: 575; 1855: pI. 37, figs. 2a-f. Coralliocaris superba - Stimpson, 1860: 38. Kemp, 1922: 272-274, figs. 98-99. Material examined. (i) 1 male, Tarn Island, stn. 3, 1.5-2 m, November 1985, NTM Cr.008423. (ii) 1 male, 1 female, idem, NTM Cr.008424. Remarks. All specimens lack both second pereiopods. The males have a rostral dentition of 412, 211 (Fig. 2A) and the female, 412 (Figs. 2B and 3B), with a distinct ventral carina, and are provisionally attributed to C. superba on account of the stronger rostral dentitions than in C. 61

A.J. Bruce

venusta, and the third maxillipeds not having the distal segment of the endopod longer than the penultimate (Fig. 3C), as in C. graminea. The third maxillipeds (Fig. 3C) also show the distinct setal basket on the distodorsal surface of the penultimate segment of the endopod, full of finely granular material, similar to that reported in C. graminea (Bruce 1976). The endopod is robust, with the ischiomeral and basal segments completely fused, the two distal segments slightly exceeding the length of the combined proximal segment, the penultimate segment about 1.3 times longer than broad, the distal segment (Fig. 3D) of similar length, about 2.5 times longer than wide, with the medial margin distinctly concave and the distal end broadly rounded. The posterior margin of the telson (Fig. 3E) is feebly angulate, without a median process, with the lateral pair of posterior marginal spines subequal to the dorsal spine length, intermediate spines robust, 5.5 times longer than basal width, subequal to posterior margin width, submedian spines 5.0 times longer than wide, densely setulose, and about 0.6 of the submedian spine length. The fourth thoracic sternite (Fig. 3F) shows a low transverse ridge, with a slight median eminence and the fifth sternite shows a larger stout, broadly triangular median process. Host. Both lots of specimens were found in associations with Acropora spp. [Sc1eractinia: Acroporidae] . Distribution. Type locality: Tongatabu. Otherwise widely reported from the Red Sea to Madagascar, Ryukyu Islands to the Great Barrier Reef, east to Tahiti. Coralliocaris venusta Kemp (Figs. 2C-E, 3GH) Coralliocaris venusta Kemp; 1922: 274-276, figs. 100-101.

Kemp's description is good, particularly in regard to the second pereiopods, the spacing of the dorsal rostral teeth is variable (Fig. 2C and D). The inferior orbital angle in the type material appears much less distinctly produced than in the present specimens. One juvenile female also has three small dorsal rostral teeth rather than the more usual two (Fig. 2D). The third maxilliped bears a setal basket (Fig. 3G), but less well marked than in C. superba. The distal segment of the endopod is feebly sinuous medially, distally angulate (Fig. 3H).

Host. Acropora sp. [Sc1eractinia: Acroporidae]. Distributions. Type locality: off Tholyram Paar, Gulf of Manaar. Also known from the Red Sea to Mozambique, Seychelle, Comoro and Maldive Islands, La Reunion, Indonesia, Japan, Marshall and Solomon Islands. Coralliocaris viridis Bruce (Figs. 2F, 31) Coralliocaris viridis Bruce, 1974c: 222-224, fig. 1. Material examined. (i) 1 male, 2 juv., Tre Island, stn. 18, 2 m, 6 March 1990, NTM Cr.008427. (ii) 1 ovig. female, idem, NTM Cr.008428. Remarks. The ovigerous female specimen has a slender, shallow rostrum, (Fig. 2F) with a low dorsal carina and a dentition of 5/2, with small acute teeth, the male, 5/1, ~nd the juveniles 4-5/ 1. The third maxilliped is also generally similar to that of C. superba. The ischiomerus: basis articulation is obsolete dorsally, distinct ventrally, and the distal segment of the endopod (Fig. 31) appears feebly grooved proximally along its concave medial margin, a feature that was not discerned in the previous species. The colour pattern of the Vietnamese specimens is unknown. Host. (i) Acropora sp. [Sc1eractinia: Acroporidae].

Material examined. (i) 2 juv., Tarn Island, stn. 3, 1.5-2 m, November 1985, NTM Cr.008425. (ii) 1 ovig. female, idem, NTM Cr.008426. Remarks. The specimen (ii) is without second pereiopods. Although the general agreement with 62

Distribution. Type locality; Mombasa, Kenya. Also known from Mozambique, Sri Lanka, Maldive Islands, Ryukyu Islands, Indonesia and the Great Barrier Reef.

Pontoniine shrimps from Vietnam

Harpiliopsis beaupresii (Audouin) (Figs. 2G, 3J-I)

Host. Pociliopora verrucosa (Ellis and Solander) [Scleractinia: Thamnasteriidae].

Palaemon beaupresii Audouin, 1825: 91. Harpilius beaupresii - Heller, 1861: 27. Harpiliopsis beaupresi - Borradaile, 1917: 324, 379, pI. 55, fig. 21.

Distribution. Type locality: Egypt. Common throughout the Indo-West Pacific region from the Red Sea to Mozambique, Ryukyu Islands to Great Barrier Reef, east to Marshall Islands and also Easter Island in the Eastern Pacific region.

Material examined. (i) 1 male, 1 ovig. female, Mung Island, stn. 22, 5-7 m, 23 March 1990, NTM Cr.008429. Remarks. The rostral dentition is: male, 6/3 (Fig. 2G); female, 612. In both, the first dorsal tooth is small and appears articulated. The rostrum is more slender in the male and the distal dorsal tooth is minute. The specimens differ slightly from the condition illustrated in Kemp (1922, p. 229, fig. 67), in which the first dorsal rostral tooth is far in advance of the level of the inferior orbital angle, whereas in the present specimens it is only slightly more anteriorly situated. The coxae of the third maxillipeds are widely separated by a broad, unarmed sternite. The endopod has the two distal segments slender, as in H. depressa, as illustrated by Holthuis (1951, pI. 22f) but the ischiomeral segment is markedly broader, distinctly angulated medially at about 0.25 of its length, where there is a small notch, proximal to which a row of some 15 short medially directed ventral submarginal setae are present. This setal row was not present in the Coralliocaris species examined, and the dorsal setal basket found on the penultimate segment in that genus was not present in the present specimen. Also noted by Holthuis (1951), the dactylus of the ambulatory pereiopod (Fig. 3K) is twisted, giving it a most characteristic appearance, diagnostic for the genus, and the ventral propod is devoid of spines, with numerous finely plumose setae. The dactylus is robust, with a dorso-medial carina and a short stout subconical unguis, with the dorsolateral surface strongly convex. The medial aspect of the corpus (Fig. 3L) is quite flat, densely covered by a pavement of small rounded squames, the ventral margin is lamellate with several short submarginal setae laterally, with a pair of more robust sensory setae distolaterally, which may clump together and produce a biunguicate appearance.

iocaste japonica (Ortmann, 1890) Coralliocaris superba var. japonica Ortmann, 1890: 509. iocaste japonica - Holthuis, 1952: 190-195. fig. 94 (partim). - Patton, 1966:279-280, fig. 3b. Bruce, 1974a: 198-199, fig. 7. Material examined. (i) 2 males, 1 ovig. female, Tre Island, stn. 4, 9 March 1990, NTM Cr.008430. (ii) 1 male, 2 ovig. female, idem, NTM Cr.008431. (iii) 1 male, Mung Island, stn. ?, 21 March 1990, NTM Cr.008432. (iv) 2 juv., Tre Island, stn. 13, 26 March 1990, NTM Cr.008433. (v) 1 male, 2 ovig. female, Tre Island, stn. 20, 5-7 m, 28 March 1990, NTM Cr.008434. (vi) 1 male, 2 ovig. female, Tre Island, stn. 21, 5 m, 29 March 1990, NTM Cr.008435. (vii) 1 ovig. female, Tre Island, stn. 9, 4-5 m, 31 March 1990, NTM Cr.008436. Remarks. The specimens show no significant differences from previous descriptions. Host. All specimens were reported from Acropora spp., except (v), which was found on Pociliopora verrucosa (Ellis and Solander), together with Philarius gerlachei. This species is not normally found in association with Pociliopora corals, and the presence of P. gerlachei, another Acropora asssociate, suggests that a labelling error may have occurred. Distribution. Type locality: Kagoshima, Japan. Also known from East Africa to the Philippines and the Cook Islands, apparently absent from the Red Sea. iocaste lucina (Nobili) Coraliiocaris lucina Nobili, 1901: 5; 1906: 57-58. 63

A.J. Bruce

iocaste lucina - Holthuis, 1952: 190-195, fig. 94 (partim). - Patton, 1966: 278-279, fig. 3a. - Bruce, 1974a: 199, fig. 8. Material examined. (1) 1 spm, unspecified locality, NTM Cr.008437. (ii) 1 male, 3 ovig. female, Tarn Island stn. 3, 1.5-2 m, November 1985, NTM Cr.008438. (iii) 4 spms., idem, NTM Cr.008439. (iv) 3 spms., idem, NTM Cr.008440. (v) 4 spms., idem, NTM Cr.008441. (vi) 1 male, 1 ovig. female, Cape Hoi, Cam Ranh Bay, 1.5 m, 12 March 1990, NTM Cr.008442. (vii) 1 male, 2 ovig. female. Tre Island, stn. 9, 18 March 1990, NTM Cr.008443. (viii) 1 ovig. female, 1 juv., stn. 20, Tre Island, 28 March 1990, NTM Cr.008444. Remarks. The specimens show no differences from previous descriptions. Hosts. All specimens were collected from Acropora spp., except for (vi), which was reported as associated with Pocillopora sp. [Scleractinia: Thamnasteriidae] . Parasites. The ovigerous female from stn. 20 was parasitized by a male-female pair of Hemiphryxus malindiae (Bruce 1974) (Isopoda: Bopyridae), det. I.C. Markham. Distribution. Type locality: Eritrea. Also known extensively throughout the Indian Ocean, and Red Sea, and western and central Pacific Oceans as far east as the Cook Islands and Iohnson Atoll.

abdominal segment (Fig. 6B) is acute. The telson (Fig. 6B) is about 2.0 times longer than wide, lateral margins convergent, straight, with the posterior margin (Fig. 6C) about 0.4 of the anterior width, convex with a small acute median point; anterior dorsal spines about 0.22 of telson length, posterior dorsal spines about 0.1, half the anterior spine length; lateral posterior spines small, subdorsal, 0.25 of intermediate spine length, intermediate spines robust, about 0.2 of telson length, submedian spines well developed, slightly smaller and more slender than intermediate spines, strongly setose medially and laterally. The posterolateral angle of the exopod (Fig. 6D) of the uropod is expanded, with a small acute tooth, the immediately adjacent spine is large, robust and strongly curved medially. The dactyl of the third ambulatory pereiopod has the unguis (Fig. 6A) much as shown in Bruce (l974b, fig. 7d), but the denticles are fewer, more acute and distally inclined.

Host. Sponge, unidentified. Distribution. Type locality: Oman, 19° 22.6'N, 57° 53.0'E, I3.5m. Also known from Djibuti, Kenya, Zanzibar, Tanganyika, Maldive Islands, Japan, Hong Kong, Great Barrier Reef, New Caledonia and Fiji. Periclimenes amymone De Man (Figs. 5A, 6E) Periclimenes amymone De Man, 1902: 829-833, pI. 25, fig. 53.

Periclimenaeus arabicus (Calman) (Fig. 6A-D) Periclimenes (Periclimenaeus) arabicus Calman, 1939: 210, fig. 4. Periclimenaeus arabicus - Holthuis, 1952: 13, 130. - Bruce, I974b: 1563-1568,1581, figs. 3 gf, 4-6, 7 c-h. Material examined. (i) 2 ovig. female, Tre Island, stn. 12, 19 March 1990, NTM Cr.008445. Remarks. The specimens correspond well with the original and subsequent descriptions, with a rostral dentition of 6/0 and 7/l, with acute supraorbital spines. The posteroventral angle of the sixth 64

Material examined. (i) 9 spms, Tarn Island, stn. 3, 1.5-2 m, November 1985, NTM Cr.008446. (ii) 1 male, 1 ovig female. Tre Island, stn. 13, 2 March 1990, NTM Cr.008447. (iii), 1 ovig. female, Tre Island, stn. 19, 7 m, 7 March 1990, NTM Cr.008448. (iv), 1 male, 1 ovig. female, 1 juv., Tre Island, stn. 18, 2-3 m, 7 March 1990, NTM Cr.008449. (v), 2 juv., Tre Island, stn. 4, 9 March 1990, NTM Cr.008450. (vi), 4 juv., Tre Island, stn. 12, 19 March 1990, NTM Cr.008451. (vii), 3 males, 1 ovig. female, Mung Island, stn. 22, 5-7 m, 23 March, 1990, NTM Cr.008452. Remarks. The specimens agree well with previous

Pontoniine shrimps from Vietnam

2.0 mm F

F

,0.3 mm , G

c

1.5mm D

D

,3.0mm

BC

I

Fig. 5. Periclimenes amymone De Man. A, carapace and rostrum. Periclimenes brevicarpalis (Schenkel). S, carapace and rostrum, male. C, same, ovigerous female. Periclimenes consobrinus (De Man). D, carapace and rostrum, ovigerous female. E, same, tip of rostrum. Periclimenes /utescens (Dana). F, carapace rostrum, male. G, same, ovigerous female. 65

A.J. Bruce

1°.2 mm I OP

10.5

mml

ABHM

G

A

N

10.3 L

0.2 mm EFGN

mml

B

10. 1 mm I

J

J

K Fig. 6.

Periclimenaeus arabicus (Calman), ovigerous female. A, third pereiopod, dactyl, unguis and distal corpus. B, sixth abdominal segment and telson. C, posterior telson spines. D, exopod of uropod, posterolateral angle. Periclimenes amymone (De Man), ovigerous female. E, third pereiopod, distal propod and dactyl. Periclimenenes brevicarpalis (Schenkel). F, third pereiopod, dactyl and distal propod, male. G, same, ovigerous female. Periclimenes consobrinus (De Man), ovigerous

female. H, third pereiopod, propod and dactyl. I, same, distal propod and dactyl, (setae not shown). J, same dactyl. Perclimenes /utescens (Dana), ovigerous female. K, third pereiopod, propod and dactyl. L, same, distal propod and dactyl. Periclimenes spiniferus De Man, ovigerous female. M, paragnaths. N, third pereiopod, distal propod and dactyl. Male. 0, first pleopod, endopod. P, second pleopod, endopod.

66

Pontoniine shrimps from Vietnam

descriptions. They were found in association with Periclimenes spiniferus and Thor sp. [Hippolytidae). The presence of a single distoventral spine in the third ambulatory pereiopod (Fig. 6E) in this species has been reported in Bruce (1980), in contradiction to the statement in Kemp (1922) that the ambulatory propods lack spines. The numerous long flexible setae on the distal propod are also flattened and with finely biserrate margins. The rostrum (Fig. 5A) in the present material is provided with numerous short densely plumose setate, in front of each dorsal tooth, and medially along the proximal ventral margin but submarginally and bilaterally along the distal portion, a condition apparently unusual in Periclimenes species. In the key to the species of the Periclimenes grandis species group provided in Bruce (1987), the substitution of the following for couplet 10 will facilitate the separation of the two species concerned: 10. Ambulatory pereiopods with propods strongly spinulate ventrally; chelae of second pereiopods tuberculate in males; R.l +6-9/2-3 ........................................... P. elegans (Paulson) Ambulatory pereiopods with at most single distoventral spine; chelae of second pereiopodsds non-tuberculate; R.l +6-9/2-3 ............ , .......... . ........................................... P. amymone De Man Host. Acropora spp; [Scleractinia: Acroporidae], except (vi), from A. gemmifera (Brooks), and (ii) (vii) from Pociilopora verrucosa (Ellis and Solander) [Thamnasteriidae]. Distribution. Type locality: Ternate, Indonesia. Also known from the Nicobar Islands, Singapore, Indonesia, Papua New Guinea, Great Barrier Reef, Solomon Islands and New Caledonia. Periclimenes brevicarpalis (Schenkel) (Figs. 5BC, 6FG) Ancylocaris brevicarpalis Schenkel, 1902: 563, pI. 13, fig. 21. Periclimenes (Ancylocaris) brevicarpalis - Kemp, 1922: 185-191, figs. 40-42, pI. 67. Material examined. (i) { male, 1 ovig. female, stn.

3, Lo Bay, Nha Trang, 26 May 1983, NTM Cr.008453. (ii) 1 male, 1 ovig. female, Cape Hoi, Cam Ranh Bay, 2 m, 12 March 1990, NTM Cr.008454. Remarks. In the larger ovigerous female, the carapace' (Fig. 5C) shows a strongly humped appearance as noted by some previous authors, much more marked than in the male (Fig. 5B). The ambulatory dactyls are minutely biunguiculate in both sexes (Fig. 6 F and G) and the pro pods are sparsely setose and devoid of spines. Periclimenes brevicarpalis has been previously recorded from Pulo Con Dua by Kemp (1922). Host. (i) from coral? (ii) sea anemone. Distribution. Type locality: Ujung Pandang, Sulawesi, Indonesia. Otherwise common and widely distributed from the Red Sea to Mozambique, Japan to the South Great Barrier Reef, east to the Marshall Islands. Periclimenes consobrinus (De Man) (Figs. 5DE, 6H-J) Harpilius consobrinus De Man, 1902: 836-840, pI. 26, fig. 54. Periclimenes consobrinus - Bruce, 1972: 403, 409, 412 (key), fig. 1b. - Holthuis, 1981: 795-796, fig. 3 i-I. Material examined. (i) 1 ovig. female, Tre Island, stn. 10, 27 March 1990, NTM Cr.008455. Remarks. The single example unfortunately lacks both second pereiopods, but in all features, corresponds exactly with previous descriptions in regard to its main diagnostic characters, i.e., the rostrum, third maxillipeds and ambulatory propods and dactyls. The rostral lamina (Fig. 5D) is deep, with a dentition of 1 + 5/4, slightly up-curved, and only slightly exceeds the scaphocerite, but distinctly exceeds the carapace length and there is no trace of a postorbital ridge. The ventral margin of the rostrum bears a single median row of short plumose setae (Fig. SE), as in P. lutescens, without bilateral submarginal rows distally, as in P. amymone. The ambulatory pereiopods also 67

A.J. Bruce

resemble those of P. lutescens, with a compressed, strongly hooked simple dactylus (Fig. 51). The propod (Fig. 5H) is about 7.0 times longer than wide, less robust than in P. lutescens, with about 8-9 transverse rows of setae (Fig. 51) distoventrolaterally, which partly conceal the dactyl, distinctly more numerous than in P. lutescens, and without spines. The colour pattern in life was not recorded, and the specimen was collected together with an ovigerous female of Alpheus lottini Guerin.

Kong. Otherwise recorded from the Red Sea to Zanzibar, Japan to southern Queensland, Australia, east to New Caledonia and Caroline Islands, but many records are in need of confirmation, due to possible confusion with P. venustus Bruce.

Host. Pociliopora verrucosa (Ellis and Solander) [Scleractinia: Thamnasteriidae].

Material examined. (i) 2 juv, Tre Island, stn. 13, 26 March 1990, NTM Cr.008460. (ii) 1 juv. female, Tre Island, stn. 20, 9-12 m, 28 March 1990, NTM Cr.008461. (iii) 1 male, 1 ovig. female, idem, NTM Cr.008462.

Distribution. Type locality: Ternate, Moluccas, Indonesia. Otherwise known only from Kenya, Tanganyika, Comoro Islands, La Reunion, southern Great Barrier Reef, Thailand and the Philippines. Periclimenes holthuisi Bruce Periclimenes holthuisi Bruce, 1969: 258-259; 1982: 244-246, fig. 7. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. 19, 5 m, 7 March 1990, NTM Cr.008457. (ii) 1 male, 1 ovig. female, idem, NTM Cr.008458. (iii) 1 male, 1 ovig. female, idem, NTM Cr.008459. Remarks. The three pairs of specimens, each collected separately, from giant anemones, all agree closely with previous descriptions, including Bruce (1989). The closely related and morphologically very similar Periclimenes venustus has been only recently distinguished from P. holthuisi. It is possible that some of the earlier records of P. holthuisi may, upon reexamination, prove to be specimens of P. venustus. The differences are discussed in Bruce (1990b). Host. Stichodactyla mertensi gigantea Brandt, 1836 (= Stoichactis gigantea Forssk~H, 1775) [Actiniaria: Stichodacty lidae]. Distribution. Type locality: Lung Ha Wan, Hong 68

Periclimenes imperator Bruce Periclimenes imperator Bruce, 1967: 53-62, figs. 23-25.

Remarks. All specimens conform closely to previous descriptions. Host. All specimens were found in association with Stichopus variegatus Semper [Holothuroidea: Stichopidae]. Distribution. Type locality, Chumbe Island, Zanzibar. Also known from the Red Sea to Mozambique, Ryukyu Islands to Great Barrier Reef, east to the Hawaiian Islands. Periclimenes lutescens (Dana) (Figs. 5FG and 6KL) Harpilius lutescens Dana, 1852:25: 1852a: 576; 1855: pI. 37, fig. 4. ?Harpilius lutescens - Kemp, 1922:235-237, figs. 72-73. Periclimenes (Harpilius) lutescens - Holthuis, 1952: 88-91, fig. 35. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. 17, 2 m, 5 March 1990, NTM Cr.008463. (ii) 1 male, 1 ovig female, Tre Island, stn. 18, 2 m, 6 March 1990, NTM Cr.008464. (iii) 1 male, 1 ovig. female, idem, NTM Cr.008465. (iv) 1 male, 1 ovig. female, idem, NTM Cr.008466. (v) 1 male, Tre Island, stn. 19, 7 March 1990, NTM Cr.008467. (vi) 3 juv., Tre Island, stn. 4, 9 March 1990, NTM Cr.008468.

Pontoniine shrimps from Vietnam

(vii) 1 male, Tre Island, stn. 12, 19 March 1990, NTM Cr.008469. (viii) 1 male, 1 ovig. female, 1 juv., idem, NTM Cr.008470.

Remarks. All specimens agree well with previous descriptions. The rostral dentition of the adult males and females (Fig. 5G) is 712, except one female with 7/3. The rostrum is distinctly shorter than the carapace length, horizontal, and deeper in females than males, with a simple median row of short plumose setae distoventrally. A distinct postorbital ridge is present, as noted by Kemp (1922), which is not apparent in the closely related P. consobrinus. The ambulatory pereipods are stout, the prop od (Fig. 6K) about 5.0 times longer than wide, more robust than in P. consobrinus, with only some 4-5 transverse rows of setae (Fig. 6L) distoventrolaterally, distinctly less conspicuous than in P. consobrinus, and without spines. Specimens (v) were found in association with Periclimenes amymone. Holthuis (1952) noted that the specimens referred to this species by Boone (1935), from Tahiti and Nuku Hiva, showed numerous distinct differences from P. lutescens s. str. Boone's illustration of the ambulatory dactyl alone is sufficiently different from that of P.lutescens to indicate that the specimens cannot belong to Dana's species, so that its occurrence further east than the Samoan Islands is yet to be demonstrated. The correct identity of Boone's material also remains to be established. Host. Specimen (vii) was found in Acropora gemmifera (Brook), all others reported from Acropora sp. [Sc1eractinia: Acroporidae]. Distribution. Type locality: Tongatabu, Cook Islands. Widely distributed from the Red Sea to Madagascar; Amami Islands, Japan, to southern Great Barrier Reef, east to Samoan Islands. Periclimenes soror Nobili Periclimenes soror Nobili, 1904: 232. - Bruce, 1978: 299-306, figs. 1-6. Material examined. (i) 1 male, 1 ovig. female, Tre Island, stn. 12,24 January 1989, NTM Cr.008471.

(ii) 1 ovig. female, Rua Island, stn. 16, 16 February 1989, NTM Cr.008472.

Remarks. The specimens do not differ from previous descriptions. Host. Culcita novaeguineae MUller and Troschel [Asteroidea, Oreasteridae]. Distribution. Type locality: Djibuti. Common and widespread throughout the Indo- West Pacific region, from the Red Sea and East Africa to the Hawaiian Islands, and also recorded in the Eastern Pacific region from Panama (Bruce 1978). Periclimenes spiniferus De Man (Fig. 6M-P) Periclimenes petitthouarsi var. spinifera De Man, 1902: 284. Periclimenes (Falciger) spiniferus - Borradaile, 1917: 324, 369, pI. 52 fig. 1. Pericilimenes (Harpilius) spiniferus - Holthuis, 1952: 76-78, fig. 30. Material examined. (i) 1 male, 3 ovig. female, without locality, NTM Cr.008473. (ii) 4 spms., Tarn Island, stn. 3, 1.5-2 m, November 1985, NTM Cr.008474. (iii) 4 spms, Tre Island, stn. 7, 2 m, 29 November 1985, NTM. Cr.008475. Remarks. Many of the specimens lack pereiopods but all second pereiopods preserved are consistent with those of P. spiniferus, as are all other morphological features. Borradaile (1917) provided one of the first illustrations of the paragnaths of a pontoniine shrimp (pI. 52, 1q), referring to the large bilobed lower lip or metastoma. The paragnaths in an ovigerous female of the present specimens (Fig. 6M) closely resembles Borradaile's figure (pI. 52, 1q). The alae are well developed, with feeble development into lobes, the distal medial margin finely spinulate, the proximal medial margin nonspinulate. The proximal median part is short and broad, with feeble carinae laterally. The ambulatory pereiopods are also as illustrated by Borradaile. The dactyl of the third pereiopod (Fig. 6N) is compressed, with a sharp ventral edge. The unguis is distinct, stout, about 69

A.J. Bruce

2.0 times longer than the basal width, about 0.5 of the corpus length. The corpus has the dorsal margin convex, with a single seta at about 0.66 of its length, the ventral margin is almost straight, and a single sensory seta is present distolaterally, and two distomedially. The propod has a pair of long distoventral spines and several similar ventral spines. The male first and second pleopods have been illustrated by both Borradaile (1917) and Holthuis (1952). In the present specimens, these appendages are similar to the earlier data. The endopod of the first pleopod (Fig. 60) is about 3.75 times longer than the distal width, distal third moderately expanded, without distomedial lobule. The proximal three fourths of the medial border bears a series of spiniform setae of distally decreasing length and size, the first finely plumose, the rest spinulose, with short plumose setae around the rest of the medial and distal half of the lateral margin. The endopod of the second pleopod (Fig. 6P) distinctly exceeds the appendix masculina, which also slightly exceeds the appendix interna. The corpus of the appendix masculina is robust, about 4.0 times longer than wide, with about 25 simple spines distributed over the whole ventral surface, with longer spines distally. The proximal medial margin of the endopod bears plumose setae. Distribution. Type locality: Ternate, Indonesia. Also known from most of the Indo-West Pacific region, east to Tahiti, but absent from Red Sea and north-western Indian Ocean.

Periclimenes sp. Material examined. (i) 1 ?, Tre Island, stn. 7, 2 m, 29 November 1985, NTM Cr.008476. Remarks. The single example belongs to the P. grandis group s. str. (Kemp 1922), but can not be identified as it lacks both second pereiopods. Philarius gerlachei (Nobili) Harpilius gerlachei Nobili, 1905: 160; 1906: 45, pI. 4, fig. 10. Philarius gerlachei. - Holthuis, 1952: 152-153, fig. 69. Material examined. (i) 2 jUv., Tre Island, stn. 12, 19 March 1990, NTM Cr.0084 77. (ii) 1 male, 1 ovig. female, Tre Island, stn. 20, 28 March 1990, NTM Cr.008478. Remarks. The specimens all have a rostral dentition of 411, with no postorbital teeth. Specimens (ii) were in association with iocaste lucina. Host. Acropora sp. [ScIeractinia: Acroporidae]. Distribution. Type locality: Arzana Island, Persian Gulf. Also known from the Red Sea to Geyser Reef, Mocambique Channel; Ryukyu Islands to southern Great Barrier Reef, east to Fijian, Samoan and Marshall Islands.

Table 1. Comparison of the pontoniine shrimp faunas of Hong Kong, Vietnam and Singapore. Species

1. 2. 3. 4. 5. 6.

7. 8. 9. 10. 11. 70

Anapontonia denticauda Anchistus austra/is Anchistus custoides Anchistus custos Anchistus demani Anchistus miersi Chernocaris placunae Conchodytes kempi Conchodytes meleagrinae Conchodytes monodactylus Coralliocaris graminea

Hong Kong

Vietnam

+

+ + + + +

Singapore

+

+ + + +

+

+ + + + +

Pontoniine shrimps from Vietnam

Table 1 (continued)

Species

12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58.

Coralliocaris superba Coralliocaris venusta Coralliocaris viridis Hamodactylus boschmai Hamopontonia corallicola Harpiliopsis beaupresii Ischnopontonia lophos Jocaste japonica Jocaste lucina Onycocaris oligodentata Onycocaris quadratophthalma Palaemonella pottsi Palaemonella ratumana Periclimenaeus arabicus Periclimeneaeus rastrifer Periclimenaeus tridentatus Periclimenes akiensis Periclimenes amymone Periclimenes brevicarpalis Periclimenes commensalis Periclimenes consobrinus Periclimenes cristimanus Periclimenes demani Periclimenes digitalis Periclimenes diversipes Peric/imenes e/egans Periclimenes grandis Periclimenes holthuisi Peric/imenes hongkongensis Peric/imenes johnsoni Periclimenes imperator Periclimenes indicus Periclimenes kempi Periclimenes /utescens Peric/imenes /anipes Peric/imenes ornatus Periclimenes parvus Peric/imenes perturbans Periclimenes seychel/ensis Periclimenes sinensis Periclimenes sorar Periclimenes spiniferus Periclimenes t%ensis Periclimenoides odontodacty/us Philarius ger/achei Philarius imperialis Pontonides sp.

Hong Kong

Vietnam

Singapore

+ + + + + +

+ +

+ + + + + + +

+ +

+ + +

+ +

+ + + +

+ + + +

+ + + + +

+ + +

+ + + +

+ + + +

+ + + + + +

+ +

+

+ +

+

+ + +

71

A.J. Bruce

Philarius imperialis (Kubo) Harpilius imperialis Kubo, 1940: 1-4, figs. 1-3. Philarius imperialis - Holthuis, 1952: 15. Material examined. (i) male, 1 ovig. female, Tre Island, stn. 4, 9 March 1990, NTM Cr.008479. (ii) 1 male, 1 ovig. female, Tre Island, stn. 20, 5-7 m, 28 March 1990, NTM Cr.008480. Remarks. The specimens are as previously described by previous authors. The males have a rostral dentition of 7-8/1, with 1-2 postorbital teeth~ the females 6-7/1, with 1-2 postorbital teeth. The specimens (i) were associated with Periclimenes amymone and Jocaste lucina, (ii) with Jocaste japonica. Hosts. (i) Acropora sp. (ii) Pociliopora verrucosa (Ellis and Solander). [Scleractinia: Acroporidae, Thamnasteriidae]. Philarius species are not generally found in association with pocilloporid hosts and it is possible that the latter record may be a labelling error. Distribution. Type locality: Bonin Island. Also known from the Red Sea to Tanganyika, La Reunion, Singapore, Indonesia, northern Australia to southern Great Barrier Reef, Coral Sea, Caroline and Marshall Islands.

Discussion Data are presently available on 58 pontoniine shrimp species from Singapore, Vietnam and Hong Kong coastal waters. Only two species, Anchistus custos and Periclimenes brevicarpalis, have so far been found to occur in all three regions. Eight species are found in both Vietnam and Singapore and only four in both Hong Kong and Vietnam. Four species are found in both Hong Kong and Singapore but have not yet been recorded from

Vietnam. This leaves 41 species (70%) that are not shared between the three localities. The Periclimenes sp., from Tre Island, is omitted from the above, as it could probably be either P. grandis or P. elegans. The comparisons above are to some extent artificial. The pontoniine coral shrimp fauna of Singapore has been sampled by Patton and reported in J ohnson (1961, 1979) and provides eight species, of which six are associated with branching corals. The coral-associated pontoniine fauna of Hong Kong consists of only two species, with one, Coralliocaris graminea associated with branching corals, reported by Stimpson (1860), but not collected since in Hong Kong waters, although abundant on most Indo- West pacific reefs. The branching coral fauna of Hong Kong is now so restricted that it has not been sampled recently and its associated crustacean fauna is unknown. The present collection from Vietnam indicates the presence of 11 coral-associated pontoniine shrimps, all living in association with branching hosts (44%). Seven species are associated with bivalve mollusc hosts (28%), two with echinoderms (8%), two with coelenterates (8%), one with a sponge host (4%) and two freeliving species (8%). The Hong Kong fauna also includes a number of trawl-caught species from shallow sublittoral waters, as does the Singapore material, which were not sampled in the Vietnamese collections, but could well occur in Vietnamese waters.

Acknowledgements I am most grateful to Dr T.A. Britaev, of the Institute of Evolutionary Animal Morphology and Ecology, Moscow, for making this collection available to me, and for donating the specimens to the Northern Territory Museum crustacean collection. Dr J.C. Markham kindly identified the bopyrid parasite.

References Audouin, V. 1825. Explication sommaire des planches de Crustaces de l'Egypte et de la

72

Syrie, publiees par Jules-Cesar Savigny, membre de I'Institute: offrant un expose des

Pontoniine shrimps from Vietnam

caracteres nature lies des genres avec la distinctions des especes. Descriptions de l'EgyPt ou receuil des observations et des recherches qui out ete faites en Egypt pendant l' expedition de I' armee francaise. Histoire naturelle 1(4 ):77-98. Boone, L. 1935. Crustacea and Echinodermata, Scientific Results of the World Cruise of the Yacht 'Alva', William K. Vanderbilt, Commanding. Bulletin of the Vanderbilt Marine Museum 6:1-263, figs. 1-13, pIs. 196. Borradaile, L.A. 1898. A revision of the Pontonidae. Annals and Magazine of Natural History 7(2):376-9l. Borradaile, L.A. 1917. On the Pontoniinae. The Percy Sladen Trust Expedition to the Indian Ocean in 1905, under the leadership of Mr. J. Stanley Gardiner. Transactions of the Linnaean Society of London, Zoology (2):323-96, pIs. 52-7. Bruce, A.J. 1967. Notes on some Indo-Pacific Pontoniinae, Ill-IX. Descriptions of some new genera and species from the western Indian Ocean and South China Sea. Zoologische Verhandelingen, Leiden 87: 1-73, figs. 1-29. Bruce, A.J. 1969. Preliminary descriptions of sixteen new species of the genus Periclimenes Costa, 1844 (Crustacea, Decapoda, N atantia, Pontoniinae). Zoologische Mededelingen, Leiden 43(20):253-78. Bruce, A.J. 1972. A review of information upon the coral hosts of commensal shrimps of the subfamily Pontoniinae, Kingsley, 1878 (Crustacea, Decapoda, Palaemonidae). Proceedings of the Symposium on Corals and Coral Reefs, 1969. Marine Biological Association of India 399-418, figs. 1-2. Bruce, A.J. 1974a. A report on a small collection of pontoniinid shrimps from the Island of Farquhar. Crustaceana 27(2): 189-203, figs 18. Bruce, A.J. 1974b. Observations on some specimens of the genus Periclimenaeus Borradaile (Decapoda Nataritia, Pontoniinae) originally described by G. Nobili. Bulletin du Museum National d'Histoire Naturelle, Paris (3)(258)(Zool.) 180: 1557-83, figs. 1-15.

Bruce, AJ. 1974c. Coralliocaris viridis sp. nov., a preliminary note (Decapoda Natantia, Pontoniinae). Crustaceano 26(2):222-4, fig. 1. Bruce, AJ. 1976. Shrimps and prawns of coral reefs. In The Biology and Geology (~r Coral Reefs (ed. O. Jones and R. Endean), 37-94, figs. 1-21, 1 tab. Academic Press. Bruce, A.J. 1977. Pontoni ine shri mps in the collections of the Australian Museum. Records of the Australian Museum 32(2):3981, figs. 1-16. Bruce, A.J. 1978. Periclimenes soror Nobili, a pontoniinid shrimp new to the American fauna, with observations on its Indo- West Pacific distribution. Tethys 8(4):299-306, figs. 1-6. Bruce, A.J. 1979. Records of some pontoniinid shrimps from the South China Sea. IndoMalayan Zoology 1(2): 215-48. Bruce, A.J. 1980. Some pontoniine shrimps from the Solomon Islands. Micronesica 16(2):2619, figs. 1-2. Bruce, A.J. 1982. The pontoniine shrimp fauna of Hong Kong. In The Marine Flora and Fauna of Hong Kong and Southern China (ed. B. Morton and C.K. Tseng), 223-84. Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. Hong Kong: Hong Kong University Press. Bruce, A.J. 1987. Redescriptions of two littleknown Indo-West Pacific palaemonid shrimps, Periclimenes calmani Tattersall and P. delagoae Barnard. Journal of Natural History 21:1415-23, figs. 1-9. Bruce, A.J. 1989. A report on some coral reef shrimps from the Philippine Islands. Asian Marine Biology 6: 173-92. Bruce, A.J. 1990a. Additions to the marine shrimp fauna of Hong Kong. In The Marine Flora and Fauna of Hong Kong and Southern China II (ed. B. Morton), 611-48. Proceedings of the Second International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. 73

A.J. Bruce

Bruce, A.J. 1990b. A new cnidarian-associated palaemonid shrimp from Port Essington, Cobourg Peninsula, Australia. Indo-Malayan Zoology 6(1989): 229-43, figs. 1-8. Bruce, A.J. 1991. Notopontonia platycheles, new genus, new species, (Decapoda: Pontoniinae) from South Australia, with remarks on Pontonia pinnophylax (Otto), the type species of the genus Pontonia Latreille. Journal of Crustacean Biology 11(4):175-90, figs. 1-14. Bruce, A.J. 1992. Additions to the marine carridean fauna of Hong Kong, with a description of a new species of Onycocaris (Crustacea: Decapoda: Palaemonidae) from Tuvalu. In The Marine Flora and Fauna of Hong Kong and Southern China III (ed. B. Morton), 329-43. Proceedings of the Fourth International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1990. Hong Kong: Hong Kong University Press. Calman, W.T. 1939. Crustacea: Caridea. Scientific Reports of the John Murray Expedition 6: 183-224, figs. 1-8. Dana, J.D. 1852. Conspectus Crustaceorum quae in Orbis Terrarum circumnavigatione, Carolo Wilkes e Classe Reipublicae Foederatae e Duce, lexit et descripsit. Proceedings of the Academy of Natural Sciences of Philadelphia 1852: 10-28. Dana, J .D. 1852a. Crustacea. United States Exploring Expeditions during the years 1838, 1839, 1840, 1841, 1842 under the command of Charles Wilkes, U.S.N. 13: 1-685. Dana, J.D. 1855. Crustacea. United States Exploring Expeditions during the years 1838, 1839, 1840, 1841, 1842 under the command of Charles Wilkes, U.S.N. 13: atlas, 1-27, pIs. 1-96. Forsskal, P. 1775. Description Animalium, Avium, Amphibiorum, Piscium, Insectorum, Vermium quae in Itinere Orientali Observavit. Heinek et Faber, Haunia, pp. 19 + xxxii, 1-164. Heller, C. 1861 Synopsis der in rothen Meere vorkommenden Crustaceen. Verhandlungen der K.K. Zoologischen botanisch Gesellshaft in Wien. 11: 1-32. Hipeau-Jacquotte, R. 1973. Etude des crevettes Pontoniinae (Palaemonidae) associees aux 74

mollusques Pinnidae a Tulear (Madagascar). 3. Morphologie externe et morphologie des pieces buccales. Tethys suppI. 5:95-116, figs. 1-7. Holthuis, L.B. 1951. A general revision of the Palaemonidae (Crustacea Decapoda Natantia) of the Americas. 1. The sub-families Euryrhynchinae and Pontoniinae. Allan Hancock Foundation Publication, Occasional Paper. 11: 1-332, pIs. 1-63. Holthuis, L.B. 1952. The Decapoda of the Siboga Expedition. Part XI. The Palaemonidae collected by the Siboga and Snellius Expeditions with remarks on other species. 11. Subfamily Pontoniinae. Siboga Expedition Monograph. 39a 1o:I-252, figs, 1-110, tab. 1. Holthuis, L.B. 1981. Descriptions of three new species of shrimps (Crustacea: Decapoda: Caridea) from Pacific Islands. Proceedings of the Biological Society of Washington 94(3):787-800, figs. 1-4. Johnson, D.S. 1961. A synopsis of the Decapoda, Caridea and Stenopodidea of Singapore with notes on their distribution and a key to the genera of Caridea occurring in Malayan waters. Bulletin of the National Museum, Singapore 30:44-79, pI. 2. Johnson, D.S. 1979. Prawns of the Malacca Straits and Singapore waters. Journal of the Marine Biological Association of India 18(1): 1-54. Kemp, S. 1922. Notes on Crustacea Decapoda in the Indian Museum. XV. Pontoniinae. Records of the Indian Museum 24: 113-208, figs. 1-105, pIs. 3-9. Kubo, I. 1940. A new shrimp, Harpilius imperialis. Journal of the Imperial Fisheries Institute, Tokyo 34:1-4, figs. 1-3. Lanchester, W.F. 1900. On some malacostracous crustaceans from Malaysia in the collection of the Sarawak Museum. Annals and Magazine of Natural History 6(7):249-65, pI.12. Man, J.G. de. 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Journal of the Linnaean Society of London, Zoology 22:1-312, pIs. 1-19. Man, J.G. de. 1902. Die von Herrn Professer

Pontoniine shrimps from Vietnam

Kiikenthal in Indischen Archipel gesammelten Dekapoden und Stomatopoden. In Ktikenthal, W., Ergebisse einer zooIogischen Forschungsreise in den MoIukken und Borneo. Abandlingen hrsg. von des Senckenbergischen Naturforschenden Gesell-schaft 24:467-929, pIs. 19-27. Miers, E.J. 1884. Crustacea. Report of the Zoological Collections made in the IndoPacific Ocean during the Voyage of H.M.S. "Alert", 1881-2, 178-322,513-75, pIs. 1835, 46-52. Nobili, G. 1901. Decapodi e Stomotopodi Eritrei del Museo Zoologico dell'Universita di Napoli. Annuairi del Museo Zoologico della R. Universita di Napoli, N.S. 1(13): 1-20. NobiIi, 1904. Diagnoses preIiminaires de vingthuit especes nouvelles de Stomatopodes et Decapodes Macroures de la Mer Rouge. Bulletin du Museum National d' Histoire Naturelle, Paris 10:228-38. Nobili, G. 1905. Decapodes nouveaux des cotes d' Arabie et du Golfe Persique. (Diagnoses preliminaires). Bulletin du Museum National d'Histoire Naturelle, Paris 11: 158-64, fig. 1. Nobili, G. 1906. Faune carcinologique de la Mer Rouge. Decapodes et Stomatopodes. Annales des Sciences Naturelles (Zoologie) (9)4: 1347, fig. 1-12, pIs. 1-11. NobiIi, G. 1906a. Crustaces Decapodes et Stomatopodes. Mission J. Bonnier et Ch. Perez (Golfe Persique, 1901). Bulletin

Scientifique de la France et de la Belgique 40:13-159, figs. 1-3, pIs. 2-7. Ortmann, A. 1890. Die Unterordnung Natantia Boas. Die Decapoden-Krebse des Strassburger Museums, met besondere Berticksichtigung der von Herrn Dr Doederlein bei Japan und bei der Liu-Kiu-Inseln gesammelten und z.Z. in Strassburger Museum aufbewahrten Formen. I Theil. Zoologische lahrbiich fiir Systematik, Geographie und Biologie der Thiere 5:437-542, pIs. 36-37. Patton, W.K. 1966. Decapod Crustacea commensaI with Queensland branching corals. Crustaceana 10(3):271-95, figs. 1-3. Peters, W. 1852. Conchodytes, eine neue in Muscheln lebende Gattung von Garneeln. Bericht iiber die zur Bekanntmachung geeigneten Verhandlungen der Kongliche Preussischen Akademie der Wissenschaften zu Berlin. 1852:588-95. Schenkel, E. 1902. Beitrag zur Kenntnis der Dekapodenfauna von Celebes. Verhandlungen des Naturforschenden Gesellscheft in Basel 13:485-585, pIs. 7-13. Stimpson, W. 1860. Prodromus descriptionis animalium evertebratorum quae in Expeditione ad Oceanum Pacificum Septemtrionalem a Republica Federato missa, C. Ringgold et J. Rogers Ducibus, Observavit et descripsit. Proceedings of the Academy of Natural Sciences, Philadelphia 1860:22-48.

75

Asian Marine Biology 10 (1993): 77-94

ASSESSING THE LIMITING FACTORS OF RED TIDE BY BOTTLE BIOASSAY* K.C. Ho1 and I.J. Hodgkiss2 ISchool of Science and Technology, Open Learning Institute of Hong Kong, Mongkok, Kowloon, Hong Kong 2Department of Botany, The University of Hong Kong, Hong Kong

Abstract The bottle bioassay technique recommended by the United States Environmental Protection Agency was applied to assess the factors limiting red tides. A study of four species of dinoflagellates isolated from Tolo Harbour showed that the red tide causative organisms were limited primarily by macro-nutrients and their growth was optimal at an N:P (atomic) ratio from 4-22. Suitable temperature, salinity and light conditions were also important. However, these environmental requirements varied from one species to another. The results of the bottle bioassay agreed with field monitoring data. It is suggested that the bottle bioassay technique provides good indications of the responses of dinoflagellates to environmental variations. A complete picture of a red tide can be produced if water quality data, meteorological data and bioassay results are suitably integrated.

Introduction Subtropical Hong Kong has been seriously affected by red tides (Environmental Protection Department, Hong Kong 1992). Tolo Harbour, a semi-enclosed embayment in the northwestern waters of Hong Kong, is most affected by these occurrences as a consequence as well as a cause of eutrophication (Holmes 1988; Lam and Ho 1989a; Wong 1989). In order to remove the nutrients which support algal blooms, the Hong Kong Government has attempted to control pollution in Tolo Harbour. Unfortunately, the control of algal blooms has been of limited success because information on the ecology and environmental requirements of the individual causative organisms is scarce. This paper examines the possibility of using a bottle bioassay to elucidate the limiting factors of four red tide causative dinoflagellates in Tolo Harbour. The results are compared with monitoring and

meteorological data for evaluation of the method.

a

comprehensive

Materials and methods Bottle test hioassay The Bottle Test Bioassay method recommended by Maestrini (l984a, b) and the United States Environmental Protection Agency (1971, 1974) was employed in the presented studies. Four dinoflagellates, namely Ceratium furca (Ehrenberg) Clap. et Lachmann, Gonyaulax polygramma Stein, Gymnodinium nagasakiense Takayama, and Scrippsiella trochoidea (Stein) Loeblich III were selected for bioassay. The objectives of the bioassay analyses were to determine: (1) the limiting factors, (2) their optimal concentrations and (3) the growth potential of the various red tide causative organisms in Tolo Harbour.

* This paper was presented at a colloqium on red tides in Hong Kong and South China convened in Hong Kong from 9-11 September 1992.

K.C. Ho & I.J. Hodgkiss

Limiting factor test. Modified artificial seawater (Burkholder 1963), to which was added an aliquot of the isolated species, was enriched with particular nutrients at different concentrations. This was done to determine which parameter and which concentration was limiting to the yield and growth rate. Two complementary procedures were conducted for each cultivated species: (a) Adding the nutrients or factors singly each positive response indicated that the nutrient (or factor) in question was in short supply, while a response no greater than the unenriched control indicated that one of the other nutrients or some other factor was limiting, or that some form of synergy was lacking. (b) Counter-checking the results by adding all the nutrients (or factors) except one - provided no inhibitors were apparently present, to see

whether the response was minimal when the omitted factor coincided with that which was limiting in procedure A. If the culture with one or more nutrients (or factors) omitted produced larger maxima than a culture receiving the complete complement, this implied that the samples already contained sufficient or excessive quantities of that element and so the enrichment resulted in a toxic or harmful concentration. The test protocols for the limiting factors analysis are summarized in Table 1. Optimal growth concentration determination. Once the identity of the limiting factors was determined, artificial seawater was differentially enriched with the particular limiting nutrients, sometimes singly and sometimes in combination, to determine which condition(s) produced maximal yields. This technique was also

Table 1. The test protocols for the limiting factor analYSis. Protocols

Strength high medium low

4500 lux ± 100 lux 3800 lux ± 100 lux 3000 lux ± 100 lux

high medium low

27°C ± 2°C 22°C ± 2°C 16°C ± 2°C

Salinity -

high medium low

33%0 ± 1%0 29%0 ± 1%0 16%0 ± 1%0

PH

high medium low

8.7 ± 0.05 8.4 ± 0.05 8.1 ± 0.05

Light

Temperature

Nitrogen (NaN0 3 for Limiting Factor Test and NH 4 CI for Optimal Growth Concentration Determination) Phosphorus (K 2 HP0 4 or Na 2 HP04 ) EDT A (Na 2 EDT A) Iron (FeCI 3 ) Trace Metals H3 B0 3 MnCI 2 -4H 2 0 ZnCI 2 CoCI 2 "6H 2 0 CuCI 2 "2H 20 Na 2 Mo0 4 "2H 2 0 78

4.2 mg - N·L-1 0.186 mg - p·L·1 300 mg·L-1 33.05 mg-Fe·L-1 0.196 mg·L-1

0.416 mg·L-l 0.032 mg·L-1 1.428 mg·L-1

0.0214 mg·L-1 7.26 mg·L-1

Red tide limiting factors

accompanied by analysis of the uptake of the nutrient by the species, hence the nutrient concentrations both before and after the culture procedures were determined by relevant chemical methods (American Public Health Association et al. 1985). Determination of growth potential. Surface water samples (1 m below surface) were collected from Inner Tolo Harbour, Outer Tolo Harbour and in the Tolo Channel leading to open oceanic waters once a month from January 1988 to March 1989. The seawater was filtered with 0.45 }...lIIl pore size membrane filters to exclude bacterial and algal contamination. Thereafter, 10 mL of the purified cultivated species (in the vegetative stage and not more than three generations after isolation by observation) was added to 100 mL of the seawater contained in a conical flask. All cultures were cultivated in an incubator with temperature and light control for final yield determination. By comparing the variations in growth during different months in water from different locations, the growth potential of that species in specific locations could be elucidated.

Chambers. Results of cultivation were tested statistically for variance and standard deviations and insignificant (P > 0.05) data were discarded. For the convenience of presentation, data in figures and tables are generally the means of triplicate samples.

Test dinoflagellates

Comparison with monitoring data

The test dinoflagellates were isolated during blooms of the organisms. They were collected by phytoplankton net hauls and were isolated by micro-pipette under an inverted microscope before enrichment so as to avoid the bias of culturing the fastest growing genotypes (Brand 1985). These cultures were maintained in F-2 (minus silicates) medium (Guillard and Keller 1984) in cell wells. Taxonomic identification followed the staining methods recommended by Dodge (1981), Throndsen (1983) and Fukuyo et al. (1990). The algal culture were incubated in a New Brunswick R27 incubator with a temperature precision of ± 0.5°C. The illumination manifolds were fixed inside the incubator and controlled by a computer operated programmer. The light/dark cycle and intensity of the incubation were thus regulated, but frequent calibration and monitoring by a portable irradiance meter was also carried out. The phytoplankton was fixed using Lugol's Iodine solution and cell counts were made under an inverted microscope using Sedgwick Rafter

The bioassay results in the present studies were compared with water quality and climatic data. The water quality data were the biweekly monitoring results collected by the Hong Kong Environmental Protection Department (Environmental Protection Department, Hong Kong 1989, 1990). Some field surveys were also conducted to supplement the information on phytoplankton succession. The climatic data were obtained from the Hong Kong Royal Observatory (1990). Some of the climatic data were reanalysed and compared with the normals in 50 years.

Data analysis The maximum yield was taken from the mean algal concentration measured at the equilibrium phase of growth. The growth rate (J..l) was estimated from cell counts in the exponential phase using the formula of Guillard (1975):

J..l=----.

where Co and Cl indicate the cell member at times To and T I , respectively.

Results Environmental requirements of Ceratium furca

The limiting factors examined for Ceratiuf!l furca were, in order of decreasing significance, high temperature (25-29°C), nitrogen, phosphorus and strong light illumination (Fig. 1). A water temperature of 25-28°C supported the highest 79

K.C. Ho & I.J. Hodgkiss

Final Algal Yield (cells.mL

o

-....,...., .... I

ASW EDTAandTM Vitamins Nitrogen Phosphorus High Temperature

Low Temperature High Ught Intensity

Low Ught Intensity Nitrogen

+ Phorphorus

Nitrogen

+ High Temperature

Nitrogen

+ Low Temperature

Nitrogen

+ High Ught Intensity

Nitrogen

+ Low Ught Intensity

Phosphorus

+ High Temperature

Phosphorus

+ Low Temperature

Phosphorus

+ High Ught Intensity

Phosphorus

+ Low Ught Intensity

High Temperature

+ High Ught Intensity

High Temperature

+ Low Ught Intensity

Nitrogen

I

300

I

I

I

I

I

I

t

)

1,500

1,200

900

600 I

1

I

I

I

Spiking Tests

I

I

I

+ Phosphorus + High Temperature

NItrogen + Phosphorus + Low Temperature ~~-----~---~-.-"

Nitrogen

+ Phosphorus + High Ught Intensity

Nitrogen

+ Phosphorus + Low Ught Intensity All Nutrients

+ High Temperature

+ High Temperature + High Ught Intensity

All Nutrients

t Confirmation Test All Nutrients - High Temperature

I

All Nutrients - Nitrogen All Nutrients - Phosphorus All Nutrients - High Ught Intensity

Fig. 1. Test of limiting factors for Ceratium 'urea on the basis of spiking analyses.

80

Red tide limiting factors

0.20

~ J: ZI

!.J

t

0.15

I z

0.10

15

30

25

20

Temperature ("Cl

Fig. 2. The maximum yields of Ceratium furea in different combination of nitrogen supply and temperature.

Table 2. Records of red tide caused by Ceratium 'urea in Tolo Harbour from 1983-89, and the variations in environmental parameters during the days of red tide. Date of red tide

Place

20.8.83

Inner Tolo

1850

28.9

0.063

0.009

14.0

18.4.86

Inner Tolo

250

24.0

0.063

0.004

11.2

4.2.88

Inner Tolo

367

20.1

0.035

0.005

6.1

6-8.6.88

Tolo Channel

1210

29.2

0.022

0.014

20.8

14-20.6.88

Inner Tolo and Channel

10860

29.6

0.015

0.005

24.7

6-7.7.88

Inner Tolo

120

30.4

0.017

0.004

22.5

12.10.88

Inner Tolo

380

27.4

0.021

0.005

18.6

27.1

0.034

0.007

Mean

Max. cell concentration (Cells.mL -1)

Mean water temperature QC

Mean soluble inorganic N (mg-N·L-1)

Mean Mean global incident soluble inorganic radiation P (mg-P·L-1) (MJ·mm-2 )

16.8 (50 years normal = 15.01) 81

K.C. Ho & I.J. Hodgkiss

yields, and this optimal temperature, when combined with a supply of nitrogenous matter (in the form of ammonium chloride), generated the maximum growth yield (Fig. 2). There was no major difference in the growth potential of this species in Inner Tolo Harbour compared with Outer Tolo Channel and Tolo Channel, suggesting that a highly eutrophicated environment (as in inner Tolo Harbour) is not sufficient to initiate a bloom or red tide of this species. According to the water quality and meteorological data, most red tides of this species occurred in periods of high water temperatures (> 29°C), prolonged sunshine (11-24 MJ·mm- l ) and low nutrient availability (Table 2). This agrees indirectly with the bioassay results in that temperature and light are playing a higher importance in controlling the blooms of Ceratium furca. Environmental requirements of Gonyaulax polygramma Gonyaulax polygramma was shown to be primarily limited by nutrients, particularly nitrogen and phosphorus (Fig. 3). According to the optimal concentration analyses, maximum yield is at an ambient N:P (atomic) ratio of 4-8 when both Nand P are supplied in abundance (Fig. 4). It is shown, however, when the ambient ammoniacal nitrogen concentration is higher than 0.15 mgN·L- I, growth is inhibited but below this critical concentration, yields are generally encouraged by ammoniacal nitrogen (Fig. 5). Variations in salinity did not affect the final yield of the species, but the initial growth was stimulated to a faster growth rate at 28-30%0 (Fig. 6). According to field records, most red tides of G. polygramma occurred at salinity of 29-31 %0 (Fig. 7), and according to the results of Lam and Yip (1990), bloom collapse of G. polygramma was associated with ammonium formation resulting from cell disintegration. These results agree with the bioassay results. Environmental requirements of Gymnodinium nagasakiense Gymnodinium nagasakiense was shown to be co82

limited by phosphorus and nitrogen (Fig. 8). Its yield was maximized at P-concentrations > 0.05 mg·L- I and a total N-concentration > 0.3 mg·VI (Fig. 9). The optimal N:P (atomic) ratio for growth ranged from 11-16. It was also shown that the species tolerated a wide range of water temperature from 19-28°C, and a salinity of 31 %0 was optimal (Fig. 10). According to the growth potential test, Gymnodinium nagasakiense had a good growth potential in eutrophic Inner Tolo Harbour, particularly from late autumn to early winter (Fig. 11). This coincides with the results by Lam and Ho (1989a, b) that blooms of this species peak during October to December each year. Environmental requirements of Scrippsiella trochoidea Scrippsiella trochoidea had its optimal growth in high temperature (> 25°C) and high light intensity (> 4500 lux) (Fig. 12). Phosphorus, however, was found to be the principal limiting factor, although enrichment with EDT A and iron also increased yields. This species had its greatest growth potential in Inner Tolo Harbour during spring to early summer (Fig. 13). During this period, phosphorus and trace metals which are accumulated in the sediment were usually replenished into the surface layers due to mixing (Environmental Protection Department, Hong Kong 1989; Lam and Ho 1989b). It thus seems that these growth limiting factors, as suggested by the bioassay experiments, are closely associated with the occurrence of Scrippsielia trochoidea red tides in the already polluted Tolo Harbour (Lam and Ho 1989a, b).

Discussion Some researchers (Eppley and Dyer 1965; Howell et al. 1967; Hare and Schmidt 1968; Ukeles 1975) have suggested the use of continuous culture techniques in algal assay. However, this method appears to favour small flagellates and diatoms, but dinoflagellates do not grow well in a relatively turbulent condition in the laboratory. Some

Red tide limiting factors

Final Algal Yield ( cells.mC

o

300

600

900

1

1,200

)

1,500

ASW

N P

~

EDTA+ Trace Metals

.9 ~

LL

Vitamins

C»

c:

;I

·e

::J

N+P N+EDTA+ Trace Metals N+Vitamins P+EDTA+ Trace Metals P+Vitamins All

Confirmation Tests AII-N AII-P AII-EDTA-Trace Metal All-Vitamins

Fig. 3. The growth responses of Gonyaulax polygramma to various additions of spikes.

83

K.C. Ho & I.J. Hodgkiss

....-. !..J

5,000

E J!l

B

4,000

1.5

4

8

12

16

20

24

28

32

36

40

N : P (atomic) Ratio Fig. 4. The yields of Gonyaulax polygramma at various N:P ratios. 3,500 . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - ,

3,000

-E

'i

..J

2,500

en

1i5

0

2,000

"U

1i5

>=

ca « caC u:

1,500

0)

1,000

500

o

+-+-+-+-+-+-~~~~~~~~-+_+-+_+~_r~~

0.03 0.05 0.08 0.10 0.13 0.15 0.17 0.19 0.21

0.23 0.25 0.27

Concentration of NH4CI Fig. 5. Inhibitive effects of ammoniacal nitrogen upon Gonyaulax polygramma growth.

84

Red tide limiting factors 2,500 . , . - - - - - - - - - - - - - - - - - - - - - - - ,

2,000

-

"!..J

E

.!d Q)

1,500

0

"0

Q)

>=

ca

C)

«

1,000

500

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16 17

Day Fig. 6. Effects of salinity change on the growth of Gonyaulax polygramma. 6

o Salinity {o/cx} Fig. 7. Red tides caused by Gonyaulax polygramma in 1983-88, and their frequency distribution in relation to salinity. 85

K.C. Ho & I.J. Hodgkiss

Final Algal Yield ( cells.m[' )

o I

ASW

1,000

500

I

I

I

1,500 I

2,500

2,000 I

I

~

Spiking Test

1

I

N P

1

EDTA+ Trace Metals Vitamins N+P + EDTA + Trace Metals N+Vitamins P + EDTA+ Trace Metals

[!

P+Vitamins Low Light

11

High Light

I

N+Low Light

N+ High Light P+Low Light

'1

P+ High Light

1

All

J

Confirmation Test

AII-N A11-P

I

'I

AII-EDTA-Trace Metals All-Vitamins - - - - . - -...----------.. ---.

-----~.11

All-High Light Fig. 8. Limiting factor determination for Gymnodinium nagasakiense by means of bottle bioassay.

86

Red tide limiting factors

1

Phosphate Concentration ( mg-P.L: 0.01

0.03

0.05

0.07

0.09

0.11

)

0.13

0.15

2,00o+---t--..f-~I----+--+---+--+---I--+--t---+--t---+--;

1,

, ,,

~

,J----- --t---~--N~-N

",

1,00

':;" (ij Cl

«

500

.

o 0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

Nitrogen Concentration ( mg-N.L"' ) Fig. 9. Effects of ammoniacal nitrogen, nitrate nitrogen and phosphates on the growth of Gymnodinium nagasakiense.

87

K.C. Ho & I.J. Hodgkiss

Salinity %0 25

26

27

28

30

29

31

32

33

1, Temperature

1 l ---y-' ____ --+-----+------1------I ---

, ,,

,,

-Salinity

500

o 15

16

17

18

19

20

21

22

23

24

25

26

27

28

Water TemperatureOC Fig. 10.

88

Effects of water temperature and salinity on the growth of Gymnodinium nagasakiense.

Red tide limiting factors

1,500 - - r - - - - - - - - - - - - - - - - - - - ,

, ,"

,

~.,...

\

"

\

'~~·~·~·Outer TOIO\

,,

.,.

I

, ' ,

... e;', .....

I

~

'""'

• • • • • • • • • • •• GJIJt ..... ••••

,.,.

1lt.

,

x~"""

,

\

.~

".'.\ ,,

....

. ................. ~---x' :

o JFMAMJJ

88

ASONDJFM

89

Fig. 11. Variations of growth potential for Gymnodinium nagasakiense in Tolo Harbour (January 1988 to March 1989).

researchers have also suggested carrying out algal assay in closed containers in situ. This, however, causes problems in controlling the environmental factors. The Bottle Test Bioassay method can indicate the environmental requirements of organisms in a relatively controlled and stable environment. Since the results of bioassay closely agreed with in situ water quality and climatic conditions, this method may be particularly useful in determining not only the identity of the primary limiting factors of dinoflagellates, but also the optimal growth concentration. Although the bottle bioassay has these

advantages, it also has one major weakness: The artificial environment of cultivation may not reflect the real situation in the natural environment (e.g., interactions between dinoflagellates, bacteria, and grazers; rapid changes in environmental conditions; neglect of certain important environmental factors) and thus, both bioassay and monitoring data should be examined. This method has been applied widely to freshwater algae but less extensively in the marine environment. Furthermore, marine studies have concentrated on the diatoms (Maestrini et al. 1984a). In order to gain a better understanding of the mechanisms of red tide formation, the present 89

K.C. Ho & I.J. Hodgkiss

Final Algal Yield ( cells.mL

o ASW

500

1,000

1 )

2,000

1,500

Spiking Test

N P EDTA+ Trace Metals Vitamins High Light Low Light High Temperature Low Temperature N+P N + P + EDTA + Trace Metals N+P+Vitamins N+P+EDTA+ Trace Metal +Vitamins Confirmation Test

AII-N

A11-P All-High Light All-High Temperature AII-EDTA-Trace Metal All-Vitamins Fig. 12.

90

Limiting factor tests for Scrippsiella trochoidea.

2,500

Red tide limiting factors 2,500

~------------------------,

Inner Tolo Harbour

.:p ..... ~.: 2,000

/8

~

6

E

~ 1,500

: .. /

(j)

\

\

0 .:.:.:0

tU

-

~

c::

0

Q..

.t:

'i

1,000

D.

e Cl

t.{

Tolo Channel ;:;J ... , Cl,·, ' ....~,

Q)

,

o

....~

I I I

I

,;...

t;1

I I

. . .. ,0

,, ,

Outer Tolo Harbour ...

I

b

,

500

o

~+---~-4--~--~--+---~~---+--~--+---r-~---+~

Jan Feb Mar Apr May Jun

~

Jul

Aug Sap Oct Nov Dec Jan Feb

MOMh

~

Fig. 13. Growth potential of Scrippsiella trochoidea in various Tolo Harbour waters during the period January 1988-February 1989.

study has been concentrated on the dinoflagellates. Since it is difficult to maintain the quality of filtered seawater and since the collection of 'pure' seawater is particularly difficult in Hong Kong because of the levels of pollution in its coastal waters, freshly prepared artificial seawater was used. Table 3 summarizes the limiting factors for the four red tide causative dinoflagellates studied. For Gonyaulax polygramma and Scrippsiella

trochoidea, phosphorus was the principal limiting factor. Moreover, three out of the four dinoflagellates studied were favoured by a N:P atomic ratio of 4-16, particularly when they were cultivated in a nutrient abundant environment. This optimal N:P (atomic) ratio for the dinoflagellates indicates a slightly nitrogen deficient condition in relation to Redfield's (1958) ratio of 16: I for the oceanic environment. This ratio was also smaller sometimes than the assimilating N:P ratio for phytoplankton (10: 1) 91

K.C. Ho & I.J. Hodgkiss

Table 3. A summary of limiting factors and optimal environmental conditions for the dinoflagellates studied.

Species

Principal limiting factor(s)

Optimal N:P Optimal Optimal (atomic ratio) illumination temperature O(C) (lux)

Optimal salinity (%0)

Ceratium furea

N

12-22

> 4500

> 25

NOE

Gonyaulax polygramma

P

4-8

< 4500

NOE

NOE

N&P

11-16

> 4500

NOE

> 29

P

6-13

> 4500

> 25

NOE

Gymnodinium nagasakiense Serippsiella troehoidea

NOE = no obvious effect proposed by Ryther and Dunstan (1971). The present results suggest therefore, that the increase of phosphorus supply and the consequent decrease in N:P ratio played a prominent role in controlling the blooms of these dinoflagellates. While nutrients (particularly phosphorus) are of major importance, salinity and irradiance are also important, although their requirements vary from one species to another. As observed in the bioassay experiments, salinity affected the dinoflagellates by reducing the period of the lag phase, Imtlatmg exponential growth and increasing the growth rate of the organisms. However, salinity did not increase the final yields of most organisms, except in the case of Gymnodinium nagasakiense which showed about a 35% increase in yield. This suggests that the effects of salinity on dinoflagellates are very nutrient dependent. The present investigation also showed that there was a higher potential for red tide occurrence

in inner Tolo Harbour than in Tolo Channel than in outer Tolo Harbour. This coincided with the red tide frequency recorded by Chan and Hodgkiss (1987) and Lam and Ho (1989b). On the basis of the bioassay results, red tides in Tolo Harbour are caused by a combination of nutrients and climatic factors acting on the natural marine ecosystem. For the effective management of red tides, therefore, minimizing the input of nutrients, particularly phosphorus, in the form of controlling sewage and industrial waste is essential.

Acknowledgements Thanks go to Mr 10e K.L. Chan for help in preparing the manuscript. This paper is dedicated to the late Dr Catherine W. Y. Lam, who contributed significantly to red tide research in Hong Kong and who advised the authors concerning the algal experiments.

References American Public Health Association. American Water Works Association and Water Pollution Control Federation 1985 Standard Methods for the Examination of Water and Wastewater. 15th ed. Published by the American Public Health Association. Burkholder, P. 1963. Some nutritional relationships among microbes of the sea sediments and water. In Symposium on Marine 92

Microbiology (ed. C.H. Oppenheimer), 13550. Thomas Springfield. Brand, L.E. 1985. Workshop: Culturing. In Toxic Dinoflagellates. Proceedings of the Third International Conference on Toxic Dinoflagellates (ed. D.M. Anderson, A.W. White and D.C. Baden), 538-9. EIsevier. Chan, B.S.S. and Hodgkiss, 1.1. 1987. Phytoplankton productivity in Tolo Harbour,

Red tide limiting factors

Asian Marine Biology 4:79-90. Dodge, J.D. 1981. Marine Dinoflagellates of the British Isles. London: HMSO. Environmental Protection Department, Hong Kong 1989. Marine Water Quality in Hong Kong. Environmental Protection Department Technical Report No. EP/.TR3/88. Hong Kong: Government Printer. Environmental Protection Department, Hong Kong 1990. Marine Water Quality in Hong Kong. Environmental Protection Department Technical Report No. EP/TR3/90. Hong Kong: Government Printer. Environmental Protection Department, Hong Kong 1992. Hong Kong Environment-A Review of 1991. Hong Kong: Government Printer. Eppley, R.W. and Dyer, D.L. 1965. Prediction of production in light-limited continuous cultures of algae. Applied Microbiology 13:833-7. Fukuyo, Y., Takano, H., Chihara, M. and Matsuoka, K. 1990. Red Tide Organisms in Japan. Uchida Rokakuho. Guillard, R.P.L. 1975. Division rates. In Chapter IV: Growth Measurement. Handbook of Phycological Methods - Culture Methods and Growth Measurements (ed. J.R. Stein), 289-312. Cambridge: Cambridge University Press. Guillard, R. and Keller, M. D. 1984 Culturing of dinoflagellates. In Dinoflagellates (ed. D.L. Sprctor), 391-443. Academic Press Inc. Hare, T.A. and Schmidt, R.R. 1968. Continuousdilution method for the mass culture of synchronized cells. Applied Microbiology 16:496-9. Ho, K.C. and Hodgkiss, I.J. 1991. Subtropical red tide: an overview of its occurrence. Asian Marine Biology 8:5-23. Holmes, P.R. 1988. Tolo Harbour - the case for integrated water quality management in a coastal environment. Journal of the Institute of Water and Environmental Management 2:171-9. Hong Kong Royal Observatory 1990. Summary of Monthly Statistics of Weather. Hong Kong: Hong Kong Royal Observatory. Howell, J.A.; Tsuchiya, H.M. and Fredrickson,

A.G. 1967. Continuous synchronous culture of photosynthetic microorganisms. Nature 214:582-4. Lam, C.W.Y. and Ho, K.C. 1989a. Red tides in Tolo Harbour, Hong Kong. In Red Tides Biology, Environmental Science and Toxicology (ed. T. Okaichi, D.M. Anderson and T. Nemoto), 49-52. Elsevier. Lam, C.W.Y. and Ho, K.C. 1989b. Phytoplankton characteristics of Tolo Harbour. Asian Marine Biology 6:5-18. Lam, C.W.Y. and Yip, S.S.Y. 1990. A threemonth red tide event in Hong Kong. In Toxic Marine Phytoplankton (ed. E. Graneli, B. Sundstrom, L. Edler and D.M. Anderson), 481-6. Elsevier. Maestrini, S.Y. 1984a. Phytoplankton as indicators of sea water quality: bioassay approaches and protocols. In Algae as Ecological Indicators (ed. L.E. Shubert), 71132. Academic Press Inc. Maestrini, S.Y. 1984b. Test algae as indicators of sea water quality: prospects. In Algae as Ecological Indicators (ed. L.E. Shubert), 13388. Academic Press Inc. Redfield, A.C. 1958. The biological control of chemical factors in the environment. Scienific Americian 46:205-21. Ryther, J.H. and Dunstan, W.M. 1971. Nitrogen, phosphorus and eutrophication in the coastal marine environment. Science 171: 1008-13. Throndsen, J. 1983. Ultra and Nanoplankton Flagellates from Coastal Waters of Southern Honshu and Kyushu, Japan (including some results from the western part of the Kuroshio off Honshu). Research Department of Fisheries Agency , Japan. United States Environmental Protection Agency. 1971. Algal Assay Procedures: Bottle Test. Corvallis: National Environmental Research Center. United States Environmental Protection Agency. 1974. Marine Algal Assay Procedure: Bottle Test. Corvallis: National Environmental Research Center. Unkeles, R. 1975. Continuous culture - a method for the production of unicellular algal foods. In Handbook of Phycological Methods: Culture Methods and Growth Measurement, 93

K.C. Ho & I.J. Hodgkiss

233-54. Cambridge: Cambridge University Press. Wong, P.S. 1989. The occurrence and distribution of red tides in Hong Kong - applications in

94

red tide management. In Red Tides Biology, Environmental Science, and Toxicology (ed. T. Okaichi, D.M. Anderson and T. Nemoto), 125-8. Elsevier.

Asian Marine Biology 10 (1993): 95-108

EFFECT OF EXPERIMENTAL HARVESTING ON KELP REGROWTH AND ON THE STRUCTURE OF THE SHALLOW-WATER COMMUNITIES OF BERING ISLAND (COMMANDER ISLANDS) V. V. Oshurkov and E.A. I vanjushina Kamchatka Institute of Ecology, Far East Science Centre, Russian Academy of Sciences, PetropavlovskKamchatsky 683000, Russia

Abstract The influence of harvesting on kelp regrowth and on the structure of kelp communities was investigated from May 1989 until July 1991 at five experimental plots in the intertidal and upper subtidal zone of Bering Island (Commander Islands). The abundance of the major kelp species (Laminaria bongardiana and L. dentigera) returned to former levels 2 to 3 years after harvesting, depending on the intensity of harvesting. At the most wave-exposed plot, where L. dentigera initially predominated, a short-term partial replacement of this species by L. bongardiana was observed. Removal of kelp in the upper subtidal zone resulted in increased kelp density. This is thought to be due to diminishing intraspecific competition leading to a lower elimination of juvenile sporophytes. Data obtained suggest that total harvesting of kelp has a negative effect on the structure and species composition of kelp communities since, two years after kelp removal, communities did not attain their pre-harvest level, in spite of a quick restoring of kelp biomass. After total harvesting, filamentous rhodophycean algae began to play an important role. They can be considered as opportunistic species. These conclusions are applicable to regions where pressure from sea otters is relatively strong since, in the absence of these predators, sea urchins should negatively influence kelp restoration.

Introduction Aspects of harvesting, aquaculture and utilization of laminarian algae are widely discussed in the scientific literature (Sarochan 1962; Kizewetter 1966; Blinova and Gusarova 1971; Smith 1985, 1986; Vozzhinskaya 1982, 1986a; Nisizawa et al. 1987). Recently, aquaculture of kelp has received more interest because the yield is more controllable. On the other hand, it cannot be managed in some regions due to harsh environmental conditions, and so harvesting of natural populations is more urgent there. Although ecologically harmless mechanized methods of harvesting exist (Pogodin 1962), they are not used. Instead, drags, 'kanza' or cables (which severely damage benthic populations) are used and these literally plough over the substrata and destroy

benthic organisms (Gemp 1962; Vozzhinskaya 1982, 1986a). It is possible to use diving methods of harvesting, or to pick up kelp newly cast ashore, or to employ limited 'mowing' in the intertidal zone during low-tide. The last two methods are especially applicable in regions where harvesting policy is governed by laws protecting the natural environment, as in the Commander Islands. Off Bering Island, five species of the genus Laminaria are found. The best for harvesting is L. bongardiana. Its lamina reaches 3 m in length, common length being about 1.5 m, and its stipe does not exceed 10 cm. This species is distributed from the intertidal zone to a depth of 10-12 m, although it is concentrated in the +0.2 to 1-2 m depth range. The next species, L. dentigera, which is distributed from 0 to 25 m depth, has a high

V.V. Oshurkov & E.A. Ivanjushina

biomass and reaches 2 m in length. However, about half of its length falls on its stipe and holdfasts, so that this species is less convenient to harvest. Another two subtidal species, L. yezoensis and L. gurjanovae, do not form thickets, and are of no interest. The last species, L. longipes, forms narrow intertidal bands in the most surf-subjected sites, occupies small areas, is about 0.5 m in length and, again, is of no harvesting interest. In 1986, the mean biomass of laminarian algae off Bering Island was 3.1 ± 0.5 kg·m- 2 , and in 1991 it reached 11.3 ± 1.7 kg·m- 2 (Oshurkov et al. 1991; Oshurkov and I vanjushina, in press). This increase in laminarian abundance appears to be due to a decline in the quantity of sea urchins, which are the main consumers of kelp. In turn, the decrease in sea urchin abundance results from increased pressure by their predator, the sea otter Enhydra lutris (Oshurkov et al. 1989, 1991; Oshurkov 1990; Oshurkov and Ivanjushina, in press). Thus, as in other regions, off Bering Island man can play a role as a kelp consumer, his harvesting policy balancing the lack of kelp utilization by sea urchins so as to prevent 'overproduction' of kelp. However, the optimum intensity of harvesting must be estimated so that an amount of kelp is obtained which will neither destroy the kelp stock nor result in irreversible changes in the shallow-water communities. Prior to this study, few investigations have been undertaken concerning the effects of harvesting on the composition and structure of near-shore kelpdominated communities. This paper deals with the effect of intensity of kelp harvesting on kelp biomass restoration, and the influence of kelp removal on the species composition, abundance and distribution of other benthic organisms. Aspects of the growth and population biology of Laminaria bongardiana are discussed elsewhere (lvanjushina and Zhigadlova, in press).

Materials and methods Bering Island is situated 103 miles off the Kamchatka Peninsula at the southern border of the Bering Sea and is separated by a gulf 196 miles wide from the Near Islands of the Aleutian arc. Investigations were carried out from May 1989

96

until July 1991 on the Pacific coast of the island at its northern part. The study site is characterized by a complicated relief involving a rocky intertidal platform with many cracks (up to 2 m in depth) resembling small fjords. Four experimental plots (each of 20 m 2) were chosen in the intertidal and upper subtidal zone in May 1989 and 1990. Plots 1 and 3 were situated in rocky cracks of the basic platform (their depth was 1.0-1.5 m); plot 2 was at 8 m and plot 4 was in a rocky intertidal basin (depth +0.3-0.5 m). All three 'crack' plots were oriented differently, relative to main wind directions. Species composition, density and biomass of laminarian algae were determined at each plot before beginning the experiment. At plot 1, in 1989, all laminarian algae exceeding 15 cm in length were removed and, in 1990,50% of the area was 'mowed' randomly. At plot 2, in 1989, total mowing of kelp was carried out. In 1990, plot 2 was divided into two halves; at the first (I) total mowing was repeated, whereas the second one (11) was undisturbed. At plot 3, in both 1989 and 1990, 50% of the area was mowed randomly. At plot 4 (chosen in 1990), total mowing of plants larger than 20 cm was carried out and only juvenile sporophytes were retained. In 1990 and 1991, the abundance of Laminaria bongardiana was estimated on the rocky reef of Fedoskina Bight, 6 km away from the main study site referred to as plot 5 later in the text. From 1987 until 1991, at this bight, limited harvesting of large specimens by natives took place during June and July. During mowing, the seaweeds were detached with knives near their holdfasts, so that no regrowth of the lamina and no damage to the substrata could take place. During each year of the experiment, kelp abundance was estimated at the same time of year in order to minimize seasonal changes in biomass. During the course of the experiment, 85 samples were obtained at plot 1; 53 at plot 2; 89 at plot 3; 118 at plot 4 and 42 at plot 5. In addition, in 1990, the abundance of kelp was estimated near plot 2 (7 samples), and in 1991 near plots 3 and 4 (20 samples each). Minimal sampling area was 0.25 m 2 during the entire experiment.

Experimental kelp harvesting

In addition, every year, biological samples were obtained at plots 1 and 2 by SCUBA divers using 0.25 m 2 quadrats, in order to check for changes in the community structure and in the abundance of benthic organisms. The numbers of samples obtained and the biomass (g·m- 2) of each taxon present are given in Tables 1 and 2. Measurements involved were: mean biomass of species (or taxa); mean density of kelp species; mean biomass of the community; species richness; and species (taxa) diversity (Shannon and Weaver 1963) calculated as H' = LPi log2 Pi

where Pi represents the share of biomass of the ith species (in rare cases, taxon) in the common community biomass.

Results Plot 1 In 1989, before the beginning of the experiment, 36 taxa were recorded from the community, including 3 species of the genus Laminaria with a total biomass of 13.69 kg·m- 2 (Table 1, Fig. 2A). The dominant species was L. dentigera, and L. bongardiana was nearly absent. Phaeophytan algae (Alaria marginata), sponges (Halichondria panicea), and rhodophytan algae (Odonthalia spp.) were also abundant and amphipods and limpets (Collisella spp.) were abundant among the vagile organisms (Table 1). In the first postharvest year (1990), considerable change occurred: the biomass of L. dentigera diminished significantly, while its density increased nonsignificantly (Table 1, Fig. 2); biomass of L. bongardiana sharply increased as well as its density (Table 1, Fig. 2); the biomass of A. marginata slightly decreased, but its density rose sharply to exceed 140 specimens'm- 2 (Table 1, Fig. 2); the abundance of filamentous rhodophytan algae increased, especially Neoptilota asplenioides and Pterosiphonia hamata; the total biomass of filamentous red algae increased almost three times (Fig. 2A) and the abundance of sponges and amphipods also altered (Table I). The total biomass of the community decreased significantly, whereas species richness increased, mainly due to

rhodophytan species (Fig. lA). New species appeared in the community, including green algae (Acrosiphonia duriuscula), phaeophytan algae (Thalassiophyllum clathrus), red algae (Ptilota spp.), and others (Table 1), but there was no significant increase in the species diversity index (Fig. lA). After 50% mowing in 1990, various changes took place during the next year: the biomass of Laminaria dentigera was restored to the preexperimental level; the abundance of L. bongardiana was significantly diminished (Table 1, Fig. 2) and the biomass of Alaria marginata slightly exceeded the initial value (Table 1, Fig. 2A). On the whole, however, the pre-experimental structure and species composition of the community was not restored. As Table 1 shows, total biomass of the community increased, as compared with the 1990 level, but it did not reach the initial value; species richness increased once more and the species diversity index was higher than in 1989 though diminished compared with the previous year (Fig. lA). Green algae (Ulva sp., Cladophora fracta) and phaeophytan algae (Thalassiophyllum clathrus) disappeared from the community in 1991_ Plot 2 The pre-experimental community consisted of 34 taxa, including three species of the genus Laminaria with a total biomass of about 2.2 kg·m- 2 (Table 2, Fig. 3A). In the first post-harvest year (1990), the value of total kelp biomass was reduced compared to the pre-harvest value (Fig. 3A), and the density of laminarian species decreased significantly (Fig. 3B). Changes in the abundance of other organisms were insignificant (Table2). At the same time, the biomass of kelp near plot 2 was 3.0 ± 0.4 kg·m- 2 and this did not differ significantly from the pre-harvest value at the plot. Mean densities of Laminaria bongardiana and L. dentigera were 17.1 ± 3.1 and 1.7 ± 0.8 specimens ·m-2, respectively. At plot 2, the biomass of the rhodophytan algae Odonthalia spp. and Constantinea rosa-marinae did not change, but abundance of N. asplenioides increased significantly. Biomass of sea urchins 97

v.v.

Oshurkov & E.A. Ivanjushina

Table 1. Changes in biomass (g·m-2 ) of taxa at plot 1 from 1989 to 1991. Taxa

1989 (n = 5)

Laminaria bongardiana (Ph) L. dentigera (Ph) 13660.0 L. longipes (Ph) 30.0 Alaria marginata (Ph) 3120.0 Clathromorphum spp. (Rh) Neoptilota asplenioides (1={h 33.2 Mikamiel/a ruprechtiana (Rh) 89.1 Porphyra sp. (Rh) Palmaria stenogona (Rh) 30.1 Odonthalia spp. (Rh) 244.0 Pterosiphonia hamata (Rh) 2.6 Pleonosporium kobayashii (Rh) 5.5 Callophyllis cristata (Rh) 1.2 Corallina pilulifera (Rh) 4.1 Phycodris riggii (Rh) 12.0 Iridaea cornucopiae (Rh) 0.9 Hydrozoa Bryozoa 3.2 Chaetomorpha tortuosa (Ch) Cerithiopsis sp. (Ga) Viva sp. (Ch) 0.6 Cladophora fracta (Ch) 0.1 Halichondria panicea (Po) 808.0 Collisella spp. (Ga) 24.6 Strongylocentrotus polyacanthus (E) 13.6 Leptasterias sp. (Ast) 3.7 Lacuna reflexa (Ga) 1.5 Epheria vincta (Ga) 0.1 Vilasina pseudovernicosa (Bi) 0.1 Amphipoda 29.8 Polyehaeta 8.2 Nemertini 0.1 Aetiniaria 7.7 Dermaturus mandtii (De) 0.2 Idothea aleutica (Is) 0.5 Lorieata 0.1 Ptilota spp. (Rh) Tokidadendron kurilensis (Rh) Rhodophyta variae Acrosiphonia duriuscula (Ch) Dichloria viridis (Ph) Thalassiophyllum clathrus (Ph) Littorina sitchana (Ga) Styela clavata (Ase) Pantopoda Cucumaria vegae (Ho) Alcyonidium sp. (Br) Modiolus fena (Bi) Bossiella cretacea (Rh) Rhodoglossum phyllocarpum (Rh) Didemnum gemmiparum (Ase) Ophiopholis aculeata (Oph) Pagurus hirsutiusculus (De) Mytilus trossulus (Bi) 98

+

± 2370.0 ± 26.0 ± 1050.0

+

± ±

28.9 47.1

+

± ± ± ± ± ± ± ±

1991 (n = 10)

1990 (n = 20)

12.6 192.0 1.1 2.6 0.8 2.8 11.5 0.7

981.0 3488.0

± 247.0 ± 1589.0

2328.0 112.0 328.0 133.0 1.2 91.2 255.0 201.0 0.1 0.3 41.7

± ± ± ± ± ± ± ± ±

10.0 0.6 259.0 14.5 0.6 16.6 0.4

± ± ±

± ±

934.0 13.0 110.0 78.0 0.6 37.3 162.0 141.0 0.1 0.2 40.8

350.0 12155.0

± 193.0 ± 1284.0

4180.0 408.0 326.0 106.0

± 1319.0 ± ± ±

6.7 96.0 30.0

+ 11.2 109.0 13.5

± ± ±

7.6 54.0 6.6

+ 0.6 11.7

± ±

0.4 4.0

+

±

3.2

+ +

0.4 ± ± 0.0 ± 628.0 ± 9.2 13.7 ±

± ± ± ±

± ±

± ±

± ± ±

2.3 1.1 0.1 0.1 24.7 6.8 0.1 5.1 0.2 0.4 0.1

± ± ± ±

0.1 3.5 0.7 0.4 1.7 0.5 0.4

±

10.0 8.8 8.8 3.9 1.3 40.5 0.7

± ± ± ± ± ± ±

± ±

± ±

± ± ±

3.1 0.4 134.0 5.3 0.4 10.4 0.1 0.0 1.0 0.3 0.1 1.2 0.4 0.3

638.0 15.2 2.7 7.2 0.3 0.1 5.2 2.7 1.8 9.2 1.2 1.5

± ± ±

± ± ±

± ±

± ±

± ±

0.1 0.0 1.6 1.5 0.7 2.6 0.7 0.7

± 6.3 4.6 5.8 2.3 1.3 38.3 0.3

10.0 41.5

± ±

6.7 20.6

0.2

±

0.1

0.1 3.0 0.2

0.1

±

0.1

2.1 0.5 1.0 0.3 0.9

± ±

2.1 0.5 0.6 0.3 0.6

+ +

0.1 3.0 0.2

± 185.0 5.6 ± 2.7 ± 6.5 ±

+

± ± ± +

Experimental kelp harvesting

Table 1

(continued)

Polyclada Hapalogaster grebnitzkii (De) Nucella freysinettii (Ga) Velutina fraudatrix (Ga) Musculus minutus (Bi)

+ + + + +

+ Means that a taxon is present but only in a small amount (less than 0.1 g.m-2 ). Asc, Ascidiae; Ast, Asteroidea; bi, Bivalvia; Br, Bryozoa; Ch, Chlorophyta; De, Decapoda; E, Echinoidea; Ga, Gastropoda; Ho, Holothuroidea; Is, Isopoda; Oph, Ophiuroidea; Ph, Phaeophyta; Po, Porifera; Rh, Rhodophyta; Si, Sipuncula.

Table 2. Changes in biomass (g·m-2 ) of taxa at plot 2 from 1989 to 1991.

Taxa

1989 (n = 6)

Laminaria bongardiana (Ph) 1907.0 ± L. dentigera (Ph) 270.0 ± L. yezoensis (Ph) 20.0 ± Alaria sp. juv. (Ph) 3.3 ± Thalassiophyllum clathrus (Ph) 157.0 ± Agarum cribrosum (Ph) 1.1 ± Clathromorphum spp. (Rh) 777.0 ± Odonthalia spp. (Rh) 273.0 ± Neoptilota asp/enioides (Rh) 12.9 ± Constantinea rosa-marinae (Rh) 33.6 ± Phycodris riggii (Rh) 0.1 ± Pterosiphonia bipinnata (Rh) 0.7 ± Dichloria viridis (Ph) 6.9 ± Chaetomorpha tortuosa (Ch) 0.8 ± Ulva sp. (Ch) 3.2 ± Actiniaria 546.0 ± Stauromedusae 0.7 ± Loricata 5.5 ± Polychaeta 3.5 ± Epheria vincta (Ga) 0.3 ± Amphipoda 0.1 ± Margarites helicina (Ga) 0.1 ± Hiatella arctica (Bi) 1.5 ± S. polyacanthus (E) 11.3 ± Synascidiae 0.1 ± Asteroidea 1.0 ± Phascolosoma japonica (Si) 3.0 ± Brachiopoda 2.3 ± Velutina fraudatrix (Ga) 0.1 ± Trichotropis sp. (Ga) 0.1 ± Bryozoa 2.0 ± Plicifusus kroyeri (Ga) 3.7 ± Phoronida 41.1 ± Dermaturus mandtii (De) + Cymathere triplicata (Ph) Palmaria stenogona (Rh) Ca/lophyl/is cristata (Rh) Rhodophyta gen. sp. Cucumaria vegae (Ho)

1990 (n = 12)

1991-1 (n = 5)

1991-11 (n = 5)

851.0 1569.0 ± 375.0 9520.0 ± 2218.0 5228.0 ± 900.0 184.0 113.0 ± 76.0 652.0 ± 364.0 894.0 ± 693.0 481.0 ± 284.0 20.8 221.0 ± 129.0 70.4 ± 40.1 1.8 6.6 ± 3.8 17.4 91.0 781.0 ± 202.0 93.4 ± 28.8 78.1 ± 1.2 0.7 6.9 0.7 ± 6.9 ± 602.0 ± 157.0 453.0 426.0 ± 121.0 662.8 ± 238.6 25.9 70.5 ± 122.6 ± 36.1 95.0 238.0 ± 79.0 5.9 79.0 ± 39.6 47.7 ± 16.7 66.2 ± 49.9 15.5 7.7 33.1 ± 11.9 8.0 ± 4.1 9.8 ± 0.1 28.2 ± 18.6 0.7 7.7 ± 4.8 0.1 0.1 ± 0.3 ± 0.3 6.9 0.9 35.4 1.6 ± 92.5 ± 55.9 58.4 ± 0.8 1.9 3.8 1.3 5.5 ± 1.9 ± 347.0 110.8 ± 110.8 322.0 ± 322.0 0.7 0.9 0.9 ± 0.3 ± 0.3 3.4 4.5 1.9 9.9 ± 4.2 ± 1.3 1.9 ± 2.3 9.9 ± 4.5 1.9 1.3 4.2 ± 1.9 ± 0.1 2.3 1.3 3.7 ± 4.1 ± 0.0 0.8 ± 0.3 0.1 0.3 ± 0.6 ± 0.1 0.1 0.3 ± 0.3 + 0.8 1.4 ± 0.3 2.6 3.4 ± 3.2 4.9 ± 7.6 1.1 2.6 1.1 ± 29.4 ± 3.4 ± 3.2 1.2 1.2 0.1 1.9 3.1 ± 0.1 ± 0.1 0.9 292.1 ± 16.1 25.3 ± 18.1 76.3 ± 70.3 2.1 1.9 11.1 ± 5.7 2.3 ± 5.1 ± 5.1 2.3 0.2 0.3 ± + + 0.1 + 0.1 1.2 0.3 ± 0.3 1.9 2.1 ± 3.7 34.9 44.7 ± 13.9 37.9 ± 19.0 +* 0.2 0.2 ± + ± 5.0 ± 3.9 1.7 ± 1.2 0.7 1.1 ± 0.3 0.8 0.7 ± 2.2 ± 1.5 ± 1.2 0.1 2.4 0.1 ± 3.6 ± 99

V.V. Oshurkov & E.A. Ivanjushina

Table 2 (continued) Nudibranchia Collisel/a spp. (Ga)· Lacuna reflexa (Ga) Halichondria panicea (Po) Porifera gen. sp. 1 (orange) Porifera gen. sp. 2 (white) Vilasina pseudovernicosa (Ga) Nemertini Ptilota spp. (Rh) Pagurus hirsutiusculus (De) Oenopota sp. (Ga) Pantopoda Hydrozoa Laminaria jurjanovae (Ph) Hommersandia palmatifolia (Rh) Halisarca dujardini (Po) Macrura gen. sp. Telmessus cheiragonus (De) Chlorophyta gen. sp. Molgula sp. (Asc) Velatocarpus pustulosus (Rh) Pleonosporium kobayashii (Rh) Mikamiel/a ruprechtiana (Rh) Puncturella sp. (Ga) Rhodymenia pertusa (Rh) Gastropoda gen. sp. Idothea aleutica (Is) Ophiopholis aculeata (Oph) Turnerella mertensiana (Rh) Rhodoglossum phyllocarpum (Rh) Kellia comandorica (Si) Polyclada Laminaria longipes (Ph)

0.1 0.1 0.8 2.7 7.6 0.6 0.3

± ± ± ± ± ± ±

0.1 0.0 0.3 2.3 7.6 0.5 0.1

0.1

±

0.1

+

11.4

+ 0.5 0.3

± ±

0.3 0.3

3.2 3.1

±

±

9.7

+

+

±

1.8

3.1

+ + 0.1 2.6 6.0 0.6 0.1 27.2 1.2 0.1

± ± ± ± ± ± ± ±

0.1 2.6 6.0 0.6 0.1 27.2 1.2 0.1

18.9

± ± ± 0.1 ± 2.0 ±

19.0 0.2

± 18.9

13.8 0.2 0.5 0.0 2.0

±

0.5

+

+ 1.5 0.9 1.3

± ± ±

1.2 0.9 1.3

+ 0.7 0.1 3.6

± ± ±

+ 16.3 0.2

0.7 0.1 3.6

± 16.3 ± 0.2 +

+ means that a taxon is present but only in a small amount (less than 0.1 g·m-2 ) * estimation of abundance of Phoronida was not carried out. For abbreviations, see Table 1.

decreased and large starfishes appeared. In 1990, sea anemones disappeared at plot 2 (Table 2). Species richness increased sharply at plot 2, but the species diversity index retained its value. Community biomass fell slightly (Fig. 1B, Table 2).

In 1991, a year after the repeated total mowing in one half of plot 2 (the 1991-1 results), the total biomass of kelp was three times as high as in 1990, and the biomass of Laminaria bongardiana had increased some six times (Table 2, Fig. 3A). The densities of the laminarian species also increased (Fig. 3B). The biomass of Odonthalia spp., Constantinea rosa-marinae, Neoptilota 100

asplenioides and starfishes diminished, but that of sea urchins and the phaeophytan alga Dichloria viridis increased, compared with the values of the preceding year (Table 2). Species richness decreased due to the disappearance of some species, but it was nevertheless higher than the initial level. Species diversity fell, however, whereas total community biomass increased significantly (Table 2, Fig. 1B). In 1991, in the non-mowed half of plot 2 (the 1991-11 results), the biomass and density of kelp species also increased, but this increase was less than in the mowed half (Table 2, Fig. 3). As in the total mowed half, a decrease in biomass of

Experimental kelp harvesting

A

"1___

/'/' /'

,/ 1

. .0

-- ------'0 -

,/

/'

B

o.

rL------~·~i, . "-

'-

"-

"-

"

11 Fig. 1. Changes in the main community characteristics from 1989 to 1991: A, plot 1; B, plot 2: I, at the 'mowed in 1990' half; 11, at the 'untouched in 1990' half. Open circles - species diversity, solid circles - community biomass, squares - species richness. Vertical lines represent ± 1 SE.

101

v.v.

Oshurkov & E.A. Ivanjushina

A

~

I ~

B

~ 1989

1990

L. bongardiana

L. dentigera

A. marginata

Rhodophyta

1991

Fig. 2. Changes in macrophytan abundance at plot 1 from 1989 to 1991: A, mean biomass; S, mean density (density of rhodophytan algae was not estimated). Vertical lines represent ± 1 SE.

Odonthalia spp., Constantinea rosa-marinae and starfishes was observed, but, conversely, the biomass of Thalassiophyllum clathrus and white sponges increased considerably, whereas the abundance of Neoptilota asplenioides and sea urchins did not change significantly (Table 2). Species richness diminished almost to the preexperimental level, but there was no significant 102

decrease in the species diversity index (Fig. IB). The two halves of plot 2 did not differ significantly from one another in terms of mean biomass of the community or the kelp and species diversity, but they differed significantly relative to the abundance of Odonthalia spp., T. clathrus, and sea urchins (Table 2).

Experimental kelp harvesting

Plot 3 Three species of laminarian algae grew initially at this plot, i.e., Laminaria bongardiana, Alaria marginata, and Thalassiophyllum clathrus. The first one dominated the biomass and the other two were rare. In the first post-harvest year (1990), the biomass and density of L. bongardiana slightly

increased (Fig. 4), but the other two species were not found. In 1991, after the repeated 50% mowing, the biomass of L. bongardiana increased once more and significantly differed from the values of both preceding years, but its density diminished to half the level of 1990 (Fig. 4). The other two laminarian species did not appear. In 1991, near plot 3, the biomass of L. bongardiana

A

B

1989

1990

1991 (I)

1991 (11)

Fig. 3. Changes in macrophytan abundance at plot 2 from 1989 to 1991: A, mean biomass; 8, mean density. In 1991, I and" respectively represent the 'mowed' and the 'untouched in 1990' halves of plot 2. Other legends as for Figure 2. 103

v.v.

Oshurkov & E.A. Ivanjushina

was 12.9 ± 2.1 kg·m- 2 , and the kelp density was 34.2 ± 5.8 specimens·m- 2, i.e., they did not differ significantly from the values at the experimental plot. Plot 4 A single kelp species, Laminaria bongardiana, was found at this plot. In 1991, a year after the experimental elimination of all the large specimens, both the biomass and the density of L. bongardiana increased significantly (Fig. 4). In 1991, near plot 4, the biomass of this species was 13.4 ± 1.8 kg·m- 2 and the density 51.0 ± 6.6 specimens·m- 2 , i.e., its biomass was comparable to plot 4, but its density was significantly less than at plot 4. Plot 5 The 1991 abundance of Laminaria bongardiana at this plot did not differ significantly from the values of 1990 (Fig. 4). Other laminarian species were not found.

Discussion The results obtained are contradictory. Apparently, the degree by which kelp stocks are restored is to a considerable extent due to patterns of local environmental conditions wave exposure, bottom slope, depth and mesorelief of substrata. Also, annual fluctuations in recruitment can play a great role (Vozzhinskaya 1986b; Paimeeva 1990). In the intertidal zone (plots 4 and 5) the total mowing of large specimens had no negative effect on kelp abundance. At the same time, in 1991, near plot 4, biomass of Laminaria bongardiana did not differ from that at the plot and was significantly higher than the initial biomass at this plot. Apparently, considerable annual variations in kelp productivity took place. In the upper subtidal zone (0-1.5 m, plots 1 and 3), different intensities of harvesting resulted in different effects. A year after total harvesting (plot 1), kelp biomass was not restored and partial replacement of one dominant species (Laminaria 104

dentigera) by another (L. bongardiana) took place. The next 50% mowing resulted in an increase in total kelp biomass as well as the biomass of the leading species L. dentigera. Biennial 50% mowing (plot 3) resulted in a significant increase in abundance of L. bongardiana, but the accompanying two macrophytan species disappeared and have not been restored up to present. At 8 m depth (plot 2) the results were, at first, unexpected. A year after total harvesting, total kelp biomass significantly diminished, though changes in the abundance of each of the laminarian species were not significant. In 1991, after a repeated total harvesting in one half of the plot, no further decrease of kelp biomass was observed and, indeed, contrary to expectations, the biomass of all the laminarian species increased considerably. A similar pattern was observed at the second (untouched in 1990) half of plot 2, where the abundance of kelp was slightly less compared to that of the first half. All these data lead to the conclusion that 1991 was a very productive year for laminarian algae. As expected, total harvesting of kelp resulted in a considerable decrease in kelp abundance. Nevertheless, rises of kelp biomass were observed on two occasions (plots 2 and 4 in 1991). Increase in biomass and (more important) density in kelp at these plots appears to be due to a diminished competition for light and substrata between the young plants. Increase in seaweed density after canopy removal has been observed by other investigators (Smith 1986; Engel 1990). It is accompanied by a decrease in phytobenthic diversity and, furthermore, because it increases sedimentation processes, it reduces future recruitment and the germination of kelp spores and gametophytes (Duggins et al. 1990). Up to now, the influence of sea urchin grazing or harvesting on the structure and species composition of benthic communities is not well investigated. Nevertheless, the data available show that changes in macrophytan abundance has a considerable effect on benthic communities (Day ton 1975a, b, 1985; Foreman 1977; Estes et al. 1978; Breen et al. 1982; Scheibling 1986; Duggins et al. 1990; Engel 1990; Scheibling and Raymond 1990). On the other hand, Smith (1985)

Experimental kelp harvesting

A

B

.....

0> <X)

0> T""

o0>

T""

0>

0> 0>

T""

T""

3

o0>

T""

o

0>

0> 0>

0> 0>

T""

T""

T""

4

T""

0> 0> T""

5

Fig. 4. Changes in abundance of Laminaria bongardiana at plots 3, 4, and 5 from 1989 to 1991. A, mean biomass; 8, mean density. Vertical lines represent ± 1 SE.

105

V.V. Oshurkov & E.A. Ivanjushina

did not record irreversible changes in the community structure after a single canopy removal. The present data show that increased kelp harvesting results in considerable changes in community structure. A year after a single total mowing at two experimental plots (1 and 2) similar effects were observed, i.e., a decrease in community biomass, increase in species richness and a rise in importance of rhodophytan algae, which appear to be opportunistic species occupying the vacant substrata. At plot 1, Laminaria bongardiana also played the role of a competitive species relative to L. dentigera. Prolonged harvesting at a different intensity partly restored the kelp biomass but the summary characteristics of kelp communities have not reattained their initial values. The experiment conducted imitates, to some extent, the elimination of kelp by sea urchins. Aspects of the interactions between kelp, sea urchins and sea otters have been discussed for some time (Estes and Palmisano 1974; Breen and Mann 1976; Duggins 1980; Day ton 1985; Van Blaricom and Estes 1987; Oshurkov et al. 1991). It is known that sea urchins, in the absence of their predator (sea otters), may destroy kelp forests and turn them into so-called sea urchin barren grounds. Over-harvesting of kelp may also result in catastrophic changes to nearshore communities (Druehl and Breen 1986). On the other hand, kelp abundance may be restored due to a decrease in sea urchin numbers caused by their mass mortality, influence of predators, or other factors (Mann 1977; Breen et al. 1982; Scheibling 1986; Oshurkov and Ivanjushina, in press). It should be noted that, unlike the natural situation, the imitated phytophagan pressure did not last all year round. This was why barren grounds were not observed at the experimental plots in this study. In addition, sea urchins graze not only sporophytes but also microscopic gametophytes and so influence kelp recruitment. During the last several years, sea otter predation was constant in the area of investigation (Sevostjanov 1984; Sevostjanov and Burdin 1987) and so sea urchins were not abundant there (Oshurkov et al. 1991; Oshurkov and Ivanjushina, in press). Thus, they did not influence kelp 106

abundance. In the absence of herbivores, kelp biomass has increased significantly in recent years. Experimental mowing of large plants resulted in a further increase in kelp abundance. No doubt, in the absence of sea otters, the process of kelp restoration will be prolonged, and kelp harvesting may become impossible. Based on observations made during this study, cut kelp laminae can regrow if the cut is situated higher than the growth zone (Ivanjushina and Zhigadlova, in press). If the cut is situated in the growth zone, however, the restored laminae take an irregular shape. It is possible that the existence of 'crooked' forms of Laminaria bongardiana (f. subsessilis and f. bifurcata) at the Commander Islands is due to irregular regrowth of the badly damaged initial form, f. taeniata. Since a plant may live for two years continually restoring its damaged lamina, the most advantageous way of harvesting would appear to involve cutting the kelp laminae higher than their growth zones.

Conclusion After the experimental removal of kelp, its biomass is restored in a short period (1-2 years) depending on the intensity of harvesting. It should be noted that this process is relatively short in the absence of herbivores. In regions where the pressure of predators (sea otters) is weak, restoration processes should proceed in another way. As a whole, in the upper subtidal zone, laminarian sporophytes are highly resilient to damaging influences. After experimental harvesting, changes in the quantitative characteristics of benthic populations and kelp communities take place, i.e., lessening in the community biomass and species diversity index, an increase in species richness, and alterations in abundance and composition of benthic species. At the most wave-exposed experimental plot, a partial short-term replacement of the dominant species Laminaria dentigera by L. bongardiana was observed. Two years after kelp removal, communities did not return to their preexperimental state. We can, therefore, conclude that total harvesting of kelp has a negative influence on the community structure as a whole.

Experimental kelp harvesting

Acknowledgements

We are very grateful to our colleagues, V. V. Shalukhanov, A.V. Rzhavsky, G.G. Zhigadlova, Vu. P. Shturmina, V.V. Strelkov, O.G. Strelkova,

and A.I. Buyanovsky, for their assistance during field data collections. We are grateful to an anonymous referee for improving the English of this paper.

References

Blinova, E.1. and Gusarova, 1.S. 1971. Algae of the subtidal zone of the south-eastern coast of Kamchatka. In Transactions of TINRO, vol. 76, 139-55. Yuzhno-Sakhalinsk. (In Russian) Breen, P.A., Carson, T.A., . Foster, J.B. and Stewart, E.A. 1982. Changes in subtidal community structure associated with British Columbia sea otter transplants. Marine Ecology Progress Series 7: 13-20. Breen, P.A. and Mann, K.H. 1976. Destructive grazing of kelp by sea urchins in eastern Canada. Journal of the Fishery Research Board of Canada 233: 1278-83. Day ton, P.K. 1975a. Experimental studies of algal canopy interactions in a sea-otter dominated kelp community at Amchitka Island, Alaska. Fishery Bulletin 273:230-7. Day ton, P.K. 1975b. Experimental evaluation of ecological dominance in a rocky intertidal algal community. Ecological Monographs 45:137-59. Day ton, P.K. 1985. The structure and regulation of some South American kelp communities. Ecological Monographs 255:447-68. Druehl, L.D. and Breen, P.A. 1986. Some ecological effects of harvesting Macrocystis integrifolia. Botanica Marina 229:97-103. Duggins, D.O. 1980. Kelp beds and sea otters: an experimental approach. Ecology 61 :447-53. Duggins, D.O., Eckman, J.E. and Sewell, A.T. 1990. Ecology of understore kelp environments. 11. Effect of kelp on recruitment of benthic invertebrates. Journal of Experimental Marine Biology and Ecology 143:27-45. Engel, S. 1990. Ecological impact of harvesting macrophytes in Halverson Lake, Wisconsin. Journal of Aquatic Plant Management 28:415. Estes, J.A. and Palmisano, J.F. 1974. Sea otters:

their role in structuring nearshore communities. Science 1985: 1058-60. Estes, J.A., Smith, N.S. and Palmisano, J.F. 1978. Sea otter predation and community organization in the western Aleutian Islands, Alaska. Ecology 59:822-33. Foreman, R.E. 1977. Benthic community modification and recovery following intensive grazing by Strongylocentrotus droebachiensis. Helgolander Wissenschaftliche Meeresuntersuchungen 30:468-84. Gemp, K.P. 1962. Seaweeds and sea grasses stocks in the White Sea and means of their further harvesting. In Proceedings of the Conference of Workers in the Algal Industry of the USSR, vol.l, 75-86. Arkhangelsk. (In Russian) Ivanjushina, E.A. and Zhigadlova, G.G. In press. Aspects of growth and population biology of Laminaria bongardiana off Bering Island (Commander Islands). Biologiya Morya, Vladivostok. (In Russian) Kizewetter, LV. 1966. Harvesting and treatment of seaweeds in Primorje. Vladivostok: Dal'izdat. (In Russian) Mann, K.H. 1977. Destruction of kelp-beds by sea urchins: a cyclical phenomenon or irreversible degradation? Helgolander Wissenschaftliche Meeresuntersuchungen 30:455-67. Nisizawa, K., Noda, H., Kikuchi, R. and Watanabe, T. 1987. The main seaweed foods in Japan. Hydrobiologia 151 :5-29. Oshurkov, V.V. 1990. Modification of the nearshore benthic ecosystem off Bering Island caused by the sea otter predation. In Marine Mammals, 228-9. Proceedings of the 10th conference on investigations, protecting and rational treatment of marine mammals in the USSR. Moscow. (In Russian) 107

v.v.

Oshurkov & E.A. Ivanjushina

Oshurkov, V.V., Bazhin, A.G., Lukin, V.I. and Sevostjanov, V.F. 1989. Sea otter predation and structure of benthic communities off the Commander Islands. Biologiya Morya, Vladivostok 6:50-60. Oshurkov, V.V., Bazhin, A.G. and Lukin, V.I. 1991. Changes in benthic structure off the Commander Islands under the impact of sea otter predation. In Natural resources of the Commander Islands. Issue 2, 171-85. Moscow: Izdatelstvo MGU. (In Russian) Oshurkov, V.V. and Ivanjushina, E.A. In press. Long-term changes in the shallow-water communities off Bering Island (Commander Islands). In Proceedings of the USSR-USA Workshop Group on Sea Otters (ed. G.R. Van Blaricom and A.M. Burdin). Paimeeva, L.G. 1990. Long-term dynamics and state of stock of Laminaria japonica flongipes (Miyabe et Tokida) Petf. in the northern Primorje. In Abstracts of the Report Session of TINRO Based on Results of 1989, 50-2. Vladivostok: TINRO. (In Russian) Pogodin, L.L. 1962. Means of further mechanization of harvesting of seaweeds. In Proceedings of the Conference of Workers in the Algal Industry of the USSR, vol.l, 75-86. Arkhangelsk. (In Russian) Sarochan, V.F. 1962. Stock of seaweeds and means of further development of seaweed harvesting in the Far Eastern seas of the USSR. In Proceedings of the Conference of Workers in the Algal Industry of the USSR, vol.l, 32-44. Arkhangelsk. (In Russian) Scheibling, R.E. 1986. Increased macroalgal abundance following mass mortalities of sea urchins (Strongylocentrotus droebachiensis) along the Atlantic coast of Nova Scotia. Oecologia 68: 186-98. Scheibling, R.E. and Raymond, B.G. 1990. Community dynamics on a subtidal cobble bed following mass mortalities of sea urchins. Marine Ecology Progress Series 63: 127-45.

108

Sevostjanov, V.F. 1984. Results of investigations on the sea otter population carried out from 1979 until 1982 at the Commander Islands. In Investigations on Marine Mammals of the Northern Pacific in 1982183, 63-8. Moscow: VNIRO. (In Russian) Sevostjanov, V.F. and Burdin, A.M. 1987. Perspectives in growth of the Bering island group of the population of sea otter from the Commander Islands. In Sea Otters and Fur Seals of the Commander Islands, 15-22. Petropavlovsk-Kam-chatsky: Dal' giz. (In Russian) Shannon, C.E. and Weaver, W. 1963. The Mathematical Theory of Communication. Urbana: University of Illinois Press. Smith, B.D. 1985. Recovery following experimental harvesting of Laminaria longicruris and L. digitata in southwestern Nova Scotia. Helgolander Wissenschaftliche Meeresuntersuchungen 39:83-101. Smith, B.D. 1986. Implications of population dynamics and interspecific competition for harvest management of the seaweed Laminaria. Marine Ecology Progress Series 33:7-18. Van Blaricom, G.R. and Estes, J.V. (eds.). 1987. The Community Ecology of Sea Otters. Berlin: Springer-Verlag. Vozzhinskaya, V.B. 1982. Influence of anthropogenic factors on benthic phytocoenoses of the Solovetzky Arc (the White Sea). In Problems of Ecology of the White Sea, Abstracts of the Conference, 602. Arkhangelsk - Solovki. (In Russian) Vozzhinskaya, V.B. 1986a. Benthic Macrophytes of the White Sea. Moscow: Nauka. (In Russian) Vozzhinskaya, V.B. 1986b. Monitoring of seaweeds of the White Sea. In Ocean Monitoring, 158-61. Moscow: Izdatelstvo lOAN USSR. (In Russian)

Asian Marine Biology 10 (1993): 109-121

BARNACLES AS BIOMONITORS OF TRACE METALS IN THE COASTAL WATERS NEAR XIAMEN, CHINA Philip S. Rainbow,! Huang Zongguo,2 Yan SongkaP and Brian D. Smith! ISchool of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London El 4NS, England. 2Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China.

Abstract The barnacles Balanus amphitrite amphitrite Darwin, Balanus uliginosus Utinomi (= B. kondakovi Tarasov and Zevina) and Tetraclita squamosa (Bruguiere) have been used as biomonitors of Zn, Cu, Cd, Pb, Cr, Ni and Ag in coastal waters of Fujian Province, China in September 1991. Analysis of Covariance was used to allow for size effects in intraspecific comparisons of the eight sites investigated. The three barnacle species occupy a range of coastal habitats, and provided consistent and complementary results on metal contamination near Xiamen and Quanzhou. Contamination gradients were particularly evident for zinc and copper at Xiamen. The three barnacle species have great potential as widespread mono specific biomonitors worldwide (B. amphitrite), throughout the lndo-Pacific (T. squamosa) and in Southeast Asian estuaries (B. uliginosus).

Introduction Work in Hong Kong (Phillips and Rainbow 1988; Chan et al. 1990; Rainbow and Smith 1992) investigated the suitability of barnacles as biomonitors of trace metals in coastal waters of the Far East. Barnacles were shown to be excellent biomonitors of local metal availabilities after allowance for body size effects, with the potential in the case of the more widespread species to act as biomonitors throughout much of the subtropical and tropical lndo-Pacific (Phillips and Rainbow 1988; Chan et al. 1990). This comparative study extends the Hong Kong work further afield to Fujian Province, China. It centres on Balanus amphitrite (strictly Balanus amphitrite amphitrite Darwin), a cosmopolitan species (Henry and McLaughlin 1975; Newman and Ross 1976) also used in the Hong Kong studies in 1986 (Phillips and Rainbow 1988; Ch an et al. 1990) and 1989 (Rainbow and Smith 1992). Another species from the Hong Kong studies, Tetraclita squamosa (Bruguiere), more typical of marine wave-washed shores, has also been used

here for comparison, with the addition of a further (more estuarine) species not previously studied as a biomonitor. This latter species is identified as Balanus uliginosus Utinomi in China, although Henry and McLaughlin (1975) preferred the name Balanus kondakovi Tarasov and Zevina for the same species (see Rainbow et al. 1989). B. uliginosus is, however, used here for reasons of familiarity to local biologists in China where the barnacle is common in low salinity estuarine habitats. Given that trace metals typically enter coastal waters via anthropogenic effluents into rivers and estuaries, the investigation of the suitability of an estuarine barnacle as a biomonitor is relevant and timely. Furthermore, B.uliginosus has a wide distribution in the Far East from southern Japan to India (Henry and McLaughlin 1975; Lewis 1985; Rainbow et al. 1989), and has the potential to be used as a metal biomonitor throughout Southeast Asia. Barnacles (Table 1) were collected from six sites in the immediate vicinity of Xiamen, Fujian Province, and from a further two sites nearer Quanzhou to the north (Fig. I). Xiamen is an

P.S. Rainbow, Z.G. Huang, S.K. Van & B.O. Smith

industrial port of approximately one million inhabitants, whereas Quanzhou is smaller with about 250,000 people. The choice of a second (potentially control) location in addition to Xiamen was considered necessary in case the coastal region of Xiamen might itself be locally atypical in terms of metal bioavailabilities. Balanus amphitrite was available at all eight sites, Tetraclita squamosa at the three more marine sites at Xiamen, and Balanus uliginosus at the lower salinity sites of Hai Cang and Song Yu affected by the Jiu Long River opposite Xiamen, and at Inner Houzhu and Outer Houzhu at the mouth of the Luo Yang River by Quanzhou (Table 1, Fig.

Quanzhou the average monthly salinity varies from 13%0 (July) to 32%0 (April) as a result of the flow of the Luo Yang River (Fig. 1), the September mean salinity being 27%0. The survey, therefore, covers sites along a gradient away from a potential contamination source (Xi amen Effluent Outfall), and sites along gradients of increasing salinity with possible physico-chemical effects on metal bioavailabilities (Phillips and Rainbow 1993).

1).

Barnacles were collected from either a pier or rocks in the eulittoral zone at 8 sites between 4 and 9 September 1991 (Table 1), and frozen on return to the laboratory. Barnacles were then identified and individual bodies of the largest available specimens dissected out using stainless steel instruments, before a brief rinse in distilled water. In the case of Balanus amphitrite, two groups of ten samples, each sample consisting of ten pooled individual bodies, were taken for analysis. For Balanus uliginosus, two groups of ten pooled samples (five bodies each) were used from Hai Cang, Inner and Outer Houzhu, but only four bodies were pooled from each of the Song Yu samples as a result of the lower abundance of barnacles there. Individual bodies of Tetraclita squamosa constituted each of the samples in the two groups of ten.

Materials and methods

During low tide at the July height of the summer wet season the water at Hai Cang is essentially the freshwater of the Jiu Long River, but surface water salinity there in September averages 18%0. September mean surface water salinities increase seawards to 29%0 at Song Yu, 30%0 at Gulang Yu and the Third Institute of Oceanography and 31 %0 at Huli Fort (Fig. 1), these figures being good approximations of yearly mean salinities at these sites. The site labelled Effluent Outfall at Xiamen (Fig. 1) receives drainage from a large lagoon, itself in a position to receive much anthropogenic domestic and industrial effluent from the city. The salinity of the harbour water by this outfall annually ranges from 25 to 32%0 with no significant freshwater input from the north of Xiamen. At Houzhu near

Table 1. Collection details of barnacles sampled. Site

Date

Barnacle species collected

Xiamen region Hai Cang (pier) Song Vu (pier) Gulang Vu (rock) Effluent outfall (pier) Third Institute of Oceanography (rock) Huli Fort (rock)

5 8 9 8 4 7

Sept. Sept. Sept. Sept. Sept. Sept.

1991 1991 1991 1991 1991 1991

Ba/anus Ba/anus Ba/anus Ba/anus Ba/anus Ba/anus

amphitrite, amphitrite, amphitrite, amphitrite amphitrite, amphitrite,

Ba/anus uJiginosus Ba/anus uJiginosus Tetraclita squamosa Tetraclita squamosa Tetraclita squamosa

Quanzhou region Inner Houzhu (pier) Outer Houzhu (pier)

110

6 Sept. 1991 6 Sept. 1991

Ba/anus amphitrite, Ba/anus uJiginosus Ba/anus amphitrite, Ba/anus uJiginosus

Metal biomonitoring in Xiamen

CHINA Quanzhou

/ Xia:n;e~ .;;...:;.:r

..... ~ 'Ho~g Kong

(J" // . ..'

TAI~AN

5km

5km

XIAMEN

~ 118~.·: ~ ..... ". '.' .-. ". .~ '.'

........ '"..

-

118°05

1

1180 10'

.

Fig. 1. Locations of six sampling sites in the Xiamen area and two near Quanzhou (larger inset) as listed in Table 1. Smaller inset shows positions of Xi amen and Quanzhou on the coast of China.

The samples of either bodies or pooled bodies were dried in pre-weighed acid-washed plastic vials to constant weight at 60°C before digestion at 100°C in conc. nitric acid (Aristar grade, BDH Ltd). One of the two groups of 10 digests for each species at each site was made up to 5 mL, the other to 2 mL with double-distilled water. Digests (or dilutions thereof) were analysed for Zn, Cu, Cd, Pb (5 mL digests) and Cr, Ni, Ag (2 mL digests) on an IL 157 Atomic Absorption Spectrophotometer (AAS) with flame atomization

and background correction. Ag measurements were made immediately on completion of digestion to reduce the danger of silver depositing from nitric acid solution. Throughout analyses, checks were made using between 3 and 6 aliquots of each of two certified reference materials (Table 2). Agreement was considered satisfactory. All metal concentrations are quoted in Jlg g-l (ppm) dry weight.

111

""U

o

I\)

::D

III

5'

0"

o

-~ N

Cv :::L c::

III ::J

co

en ~

-<

III ::J

Table 2. Metal concentrations (l1g.g.1) measured in samples (n = 3 to n = 6) of two standard reference materials compared against certified concentrations. n.m. - not measured. Reference material

!D

!=' en 3

zinc

Copepod homogenate Measured MA - A - 1 (TM) Certified [IAEA, Monaco] ± 1 SE Oyster Tissue 1556a [NIST, USA]

S20

Measured Certified ± 95% CL

181 ± 158 ±

cadmium

copper 8 2

1198 ± 275 830 ± 57

7.3 ± 7.6 ±

0.6 0.2

66.1 ± 21.6 66.3 ± 4.3

n.m.

5.66 ± 0.41 4.15 ± 0.48

lead 2.6 2.1

± 0.2 ± 0.3

1.43 ± 0.64 0.37 ± 0.01

chromium

nickel

silver

2.7 ± 0.3 1.1 ± 0.2

n.m.

0.67 ± 0.13 0.33 ± 0.06

1.99± 1.37 1.43 ± 0.46

3.8 ± 1.0 2.3 ± 0.4

1.20 ± 0.33 1.68 ± 0.15

g:

Metal biomonitoring in Xiamen

Table 3. Zinc concentrations (Jlg.g-1) in Ba/anus amphitrite (0.006 g mean body weight), Ba/anus uliginosus (0.1 g mean body weight) and Tetraclita squamosa (0.1 g body weight) with 95% confidence limits (CL), as estimated from best fit regressions log y log a + b log x, where y is the metal concentration (Jlg.g-1) and x is the (mean) dry weight (g) of the barnacle body. Samples showing any common letter in the ANCOVA column are not significantly different (P > 0.05) in zinc concentration.

=

Site

Ba/anus amphitrite

Ba/anus uliginosus

Tetraclita squamosa

Zn conc.

CL

ANCOVA

Zn conc.

CL

ANCOVA

Inner Houzhu

6965

10691 4537

a

2966

4200 2095

a

Effluent Outfall

4603

15834 1338

a, b

Song Yu

4100

5437 3072

b, c

1528

2219 1052

b, c

Institute of Oceanography

3049

6335 1463

c

13599

18671 9904

a

Gulang Yu

3483

8572 1415

c

6922

9103 5370

b

Huli Fort

3143

4563 2165

c

5059

10963 2335

b

Hai Cang

1467

2203 977

d

1942

3123 1208

b

Outer Houzhu

1575

1768 1403

d

1163

1801 751

c

Statistical analysis

Since barnacles might show significant effects of body size on accumulated metal concentrations even after choice of the largest available individuals, allowance must be made for size effects (Phillips and Rainbow 1988; Chan et al. 1990). Data for each metal for each species at each site were transformed logarithmically (to increase fit of the data to normal distributions for parametric statistics), and the equation of the best fit straight regression line calculated by least squares for log metal concentration (y) in f..Lg g-' against log dry weight (x) in g where x is the body dry weight or mean body dry weight in the case of pooled bodies. Analysis of Covariance

Zn conc.

CL

ANCOVA

(ANCOV A) was then used to test for significant differences in log y (transformed metal concentration) between regression lines fitted to each set of data for one species, having allowed for differences in log x (transformed body dry weight). For convenience, such comparisons can be tabulated in terms of metal concentrations of bodies of each barnacle species from the different sites at a standardized body weight. These standardized body weights were chosen from approximately the middle of the range of body weights analysed, and were 0.006 g for Balanus amphitrite and 0.1 g for both Balanus uliginosus and Tetraclita squamosa. For ease of comparison with 1986 and 1989 data for Hong Kong (Chan et al. 1990; Rainbow and Smith 1992), body metal

113

P.S. Rainbow, Z.G. Huang, S.K. Yan & B.O. Smith

Table 4. Copper concentrations (Jlg.g-1) in barnacles. For details see legend to Table 3. Site

Ba/anus uliginosus

Ba/anus amphitrite

Tetraclita squamosa

ANCOVA

Cu conc.

CL

b, c

15.0

20.9 10.7

a

110 48.5

c

16.6

35.1 7.9

a

63.7

92.8 43.7

c

16.0

19.3 13.3

a

Song Vu

43.1

50.6 36.8

d

70.7

102 49.0

b

Outer Houzhu

37.1

51.4 26.8

d

61.3

94.9 39.6

b

Hai Cang

34.4

53.1 22.3

d

61.5

79.6 47.6

b

CL

ANCOVA

Effluent Outfall 182

416 79.9

a

Inner Houzhu

92.2

114 74.4

b

Gulang Vu

79.8

145 43.8

Huli fort

73.2

Institute of Oceanography

Cu conc.

Cu conc.

90.7

concentrations were also estimated for bodies of B. amphitrite of 0.004 g and bodies of T. squamosa of 0.02 g.

Results There were significant relationships (P < 0.05) between body dry weight and metal concentration (double log regressions) in 3 of 48 data sets for Balanus amphitrite, 6 of 26 data sets for Balanus uliginosus, and 4 of 14 data sets for Tetraclita squamosa confirming the need to make allowances for size effects even after the choice of the largest available barnacles. ANCOV A fulfils this need allowing comparison of accumulated metal concentrations after allowing for differences in dry weight, with the precondition that the regression coefficients (slopes) of the regression lines compared do not themselves differ significantly. This was usually the case, one 114

CL

106 77.5

ANCOVA

a

exception being the comparison of cadmium concentrations in B. uliginosus. Zinc concentrations in barnacle bodies are shown in Table 3 with sites ranked in approximate decreasing order of metal concentrations, more emphasis being placed on significant differences identified by ANCOV A than on small numerical intraspecific differences deemed insignificant by ANCOV A. The three barnacles present a consistent story. Zinc bioavailabilities were high at Inner Houzhu, Quanzhou and at the Effluent Outfall site at Xiamen. There was a decrease in zinc bioavailability downstream at Houzhu, and seawards at Xiamen past Song Yu, the Third Institute of Oceanography, Gulang Yu and Huli Fort. There was no evidence for raised zinc bioavailability at Hai Cang, directly affected by the reduced salinity of the Jiu Long River. Copper concentrations are ranked in Table 4. As for zinc, copper bioavailabilities were high at the Effluent Outfall site and Inner Houzhu and

Metal biomonitoring in Xiamen

Table 5. Cadmium concentrations (Jlg.g-1) in barnacles. For details see legend to Table 3. (*slope significantly different cf. other regressions).

Gulang Vu

Ba/anus u/iginosus

Ba/anus amphitrite

Site

Cd conc.

CL

ANCOVA

11.9

32.3 4.38

a

Cd conc.

CL

ANCOVA

Tetraclita squamosa Cd conc.

CL

ANCOVA

17.7

20.4 15.4

a

Song Vu

8.73

10.8 7.04

a, b

Huli Fort

7.82

12.2 5.02

a, b

16.8

33.3 8.5

a

Institute of Oceanography

7.65

18.7 3.13

a, b

19.9

21.3 18.6

a

Effluent Outfall

6.22

20.1 1.93

a, b

Inner Houzhu

5.65

6.51 4.91

a, b

8.7

11.7 6.5

*

Outer Houzhu

5.02

6.46 3.91

b

6.6

11.3 3.9

a

Hai Cang

6.46

8.96 4.66

a, b

5.9

8.2 4.3

b

decreased seawards. Copper bioavailability was low at Hai Cang. Cadmium concentrations (Table 5) showed little variation over the sites sampled, indicating a lack of point source contamination. There was no evidence for enhancement of cadmium bioavailability at either of the low salinity sites at Hai Cang or Inner Houzhu. Lead concentrations (Table 6) showed little variation in the Xiamen area, again indicating a lack of a specific source of pollution, although bioavailabilities appeared somewhat raised at Houzhu, in comparison to Xiamen. There were no significant differences in the accumulated concentrations of chromium (Table 7) in the different samples of either Balanus amphitrite or T etraclita squamosa from Xiamen or Quanzhou. Data for B. uliginosus, however, indicated raised chromium bioavailability at Song Vu, and low bioavailability at Outer Houzhu (Table 7).

6.9

8.6 5.5

a

Nickel concentrations (Table 8) were usually below detection limits, i.e., < 2.1 - < 6.9 Jlg g-I for B. amphitrite, < 1.4 - < 6.9 Jlg g-I for B. uliginosus and < 0.7 - < 2.9 Jlg g-I for T. squamosa. B. uliginosus from Inner Houzhu, however, had higher accumulated nickel concentrations than those at Outer Houzhu, presumably themselves raised above Xiamen levels. Silver concentrations (Table 9) only showed significant variation in B. uliginosus, bioavailability being raised at Song Vu.

Discussion The three barnacle species have proved successful biomonitors of trace metals in the coastal waters of Fujian Province, providing a consistent picture of metal bioavailability. Sources of heavy metals to barnacles would include both dissolved metal and metal either 115

P.S. Rainbow, Z.G. Huang, S.K. Van & B.O. Smith

Table 6. Lead concentrations (l1g.g-1 ) in barnacles. For details see legend to Table 3. nd: not detectable « 6.3 - < 11.5 I1g.g-1). Site

Ba/anus amphitrite

Tetraclita squamosa

Ba/anus u/iginosus

Pb conc.

CL

ANCOVA

Pb conc.

CL

Inner Houzhu

7.02

34.0 1.45

a

8.57

11.4 6.45

a

Outer Houzhu

3.57

4.70 2.72

b

8.49

16.2 4.44

a, b

Song Vu

7.41

9.79 5.62

a

5.19

8.17 3.30

b, c

Gulang Vu

5.25

9.14 5.62

b

nd

Institute of Oceanography

4.40

9.02 2.15

b

10.6

20.5 5.5

a

Huli Fort

3.59

7.07 1.83

b

11.3

16.4 7.8

a

Hai Cang

3.48

6.13 1.97

b

Effluent Outfall

3.05

5.71 1.62

b

adsorbed onto or incorporated into suspended food particles. Species of Balanus feed both by captorial feeding on larger particles using the larger three posterior pairs of thoracic limbs (cirri), and by microfiltration of smaller particles (microfeeding) using the setae of the smaller anterior cirri (Crisp and Southward 1961; Anderson 1981). It is now known (Hunt and Alexander 1991) that Tetraclita squamosa is also capable of both captorial feeding and microfeeding. Thus, all three barnacles are potentially feeding on a similarly wide size range of suspended food particles - the nature of the food particles varying with their different habitats. Thus, T. squamosa will be exposed to less turbid water than the estuarine B. uliginosus with associated differences in adsorbed metal contents of ingested particles. Any inconsistencies between the barnacle species concerning the bioavailabilities of heavy metals are probably 116

4.27

9.55 1.91

ANCOVA

Pb conc.

CL ANCOVA

c

attributable to differences in metal contents of ingested food, all barnacles being expected to respond similarly to variations in dissolved metal concentrations. It is valid to compare rank orders of accumulated metal concentrations in the different barnacle species but it is not valid to make direct interspecific comparisons of absolute accumulated metal concentrations (Phillips and Rainbow 1988). What constitutes a high or low accumulated metal concentration will vary interspecifically according to interspecific differences in metal uptake rates (see Nugegoda and Rainbow 1989; Weeks and Rainbow 1991), growth rates diluting accumulated metal contents, and age (Rainbow 1987). Of the barnacles analysed here, Balanus amphitrite shows maximum settlement at Xiamen in May and June with' the population dying off each winter (Huang, unpublished data). Thus, the B. amphitrite collected in September were 3-4 months old.

Metal biomonitoring in Xi amen

Table 7. Chromium concentrations (/lg.g-l) in barnacles. For details see legend to Table 3.

Site

Ba/anus amphitrite

Cr conc.

Cl

Ba/anus uliginosus

ANCOVA

Cr conc.

Cl

ANCOVA

Tetraclita squamosa

Cr conc.

Cl

ANCOVA

Song Vu

3.23

5.37 1.94

a

6.62

10.9 4.03

a

Inner Houzhu

5.77

11.2 2.97

a

3.76

6.12 2.31

b

Institute of Oceanography

3.72

8.00 1.73

a

16.2

54.5 4.8

a

Gulang Vu

3.49

7.79 1.57

a

18.2

25.4 13.1

a

HaiCang

2.93

3.63 2.37

a

4.24

5.10 3.53

b

Outer Houzhu

3.47

4.66 2.58

a

2.50

3.45 1.81

c

Effluent Outfall

2.99

4.06 2.20

a

Huli Fort

2.13

5.21 0.87

a

11.1

15.8 7.8

a

Table 8. Nickel concentrations (/lg.g-l) in Ba/anus uliginosus. For details see legend to Table 3.

Site

Ba/anus uliginosus

Ni conc.

Cl

ANCOVA

Inner Houzhu

3.17

7.43 1.35

a

Outer Houzhu

2.60

5.13 1.31

b

Balanus uliginosus settle at Xi amen in April and reach maximum size by September, populations again failing to survive over winter (Huang, unpublished data). The B. uliginosus analysed were therefore 5 months old. Tetraclita squamosa on the other hand can survive more than two years at Xiamen (Huang, unpublished data) and the individuals collected were considered to be 2

years old. The balance of growth rate against net accumulation rate of metal content produces the final accumulated metal concentration and so it is important to make collections of barnacles to be compared over a limited time period. This precondition was met here, but is relevant when comparing Xi amen data with those for Hong Kong. The use of ANCOVA further eliminates 117

P.S. Rainbow, Z.G. Huang, S.K. Van & B.O. Smith

Table 9. Silver concentrations (Jlg.g-1) in barnacles. For details see legend to Table 3. Site

Ba/anus amphitrite

Ba/anus uliginosus

Cr conc.

CL

ANCOVA

Cr conc.

CL

Song Yu

0.66

0.98 0.44

a

1.58

2.53 0.99

a

Hai Cang

0.88

1.17 0.66

a

0.85

1.26 0.57

b

Outer Houzhu

0.55

0.79 0.38

a

0.72

1.30 0.39

b, c

Inner Houzhu

0.92

1.68 0.50

a

0.31

0.47 0.20

c

Huli Fort

0.74

2.71 0.20

a

Gulang Yu

0.73

1.44 0.37

a

Effluent Outfall

0.70

1.07 0.46

a

Institute of Oceaography

0.61

1.06 0.35

a

size effects on accumulated metal concentrations, compensating further (at least partially) for effects of age differences. The barnacle data showed the Effluent Outfall site at Xiamen to be contaminated by zinc and copper with metal availabilities decreasing seawards. Such contamination would be attributable to the proximity of industrial development at Xiamen, although no such contamination trends were evident for cadmium, lead, chromium or silver. Low salinity is known to enhance the bioavailability of both zinc (Nugegoda and Rainbow 1989) and cadmium (Sunda et al. 1978), but the Xi amen data did not indicate any raised bioavailability of these metals to barnacles at Hai Cang. Presumably any bioavailability enhancement effects of low salinity are more than compensated for by the dilution effect of the Jiu Long River. The rank position of Song Yu in zinc 118

ANCOVA

Tetraclita squamosa CL

ANCOVA

2.70

6.12 1.20

a

3.70

6.68 2.05

a

4.27

9.85 1.85

a

Cr conc.

and cadmium data lists may result from its relative proximity to Xiamen itself, somewhat lowered salinity or a combination of both. The lower salinity site of Inner Houzhu near Quanzhou did show a high bioavailability of zinc, possibly as a result of low salinity and local zinc contamination acting in combination. There was no apparent enhancement of cadmium bioavailability by low salinity at Inner Houzhu. Thus the effects of low salinity on speciation of zinc and cadmium in this study have not been of overriding significance in comparison to other processes affecting the bioavailability of these metals to the barnacles (see also Luoma et al. 1990). In order to assess the suitability of the barnacles as widespread metal biomonitors, it is relevant to attempt comparisons of the Xi amen and Quanzhou data against data for Balanus amphitrite and Tetraclita squamosa collected in Hong Kong in 1986 (Chan et al. 1990) and 1989

Metal biomonitoring in Xiamen

Table 10. Comparisons of maximum and minimum body metal concentrations (J..lg.g-1, 95% confidence limits - CL) in Balanus amphitrite of 0.004 g mean body dry weight, and Tetraclita squamosa of 0.02 g body dry weight (each estimated from best-fit double log regressions of metal concentration against (mean) body dry weight) collected in Hong Kong in 1986 (from Ch an et al. 1990) and 1989 (from Rainbow and Smith 1992), and in Fujian Province, in 1991 (this study). nm - not measured. Hong Kong 1989

Hong Kong 1986

Fujian 1991

conc.

Cl

conc.

Cl

conc.

Cl

max.

11990

15940

2726

37850 6713 30137 1069

6965

min.

14070 10220 7688 967

10691 4537 2203 977

max.

7868

11416

2245

27816 4794 5274 361

13599

min.

9160 6759 3555 1414

max.

3472

ZINC

B. amphitrite

T. squamosa

5677

1379

1467

5059

18671 9904 10963 2335

COPPER

B. amphitrite

min.

T. squamosa

max.

59.3 203

min.

14.9

max.

10.1

min.

2.1

max.

7.7

min.

3.6

max.

39.2

min.

1.7

max.

4.4

min.

2.2

max.

28.0

3950 3052 195 18.0 243 170 24.3 9.1

4865 239 81.3 28.1

8078 2930 596 95.7 174 38.1 38.4 20.5

182 34.4 16.6 15.0

416 79.9 53.1 22.3 35.9 7.9 20.9 10.7

CADMIUM

B. amphitrite

T. squamosa

11.5 8.9 2.5 1.7 12.6 4.7 4.4 2.9

30.9 9.4 13.7 8.0

33.4 28.7 16.4 5.4 17.3 10.9 11.2 5.7

11.9 5.0 19.9 16.8

32. 3 4. 4 6.5 3. 9 21. 3 18. 6 33. 3 8. 5

lEAD

B. amphitrite

T. squamosa

68.6 22.4 2.4 1.3 6.9 2.7 5.1 0.9

116 10.6 12.5 0.8

126 112 411 0.3 25.4 6.2 21.6 0.03

7.4 3.1 11.3 10.6

9. 8 5. 6 5. 7 1. 6 16. 4 7. 8 20. 5 5. 5

CHROMIUM

B. amphitrite

min.

0.22

35.0 22.4 6 x 108 0

56.3 1.8

83.0 38.2 14.1 0.2

5.8 2.1

11. 2 3. o 5. 2 O. 9

119

P.S. Rainbow, Z.G. Huang, S.K. Van & B.O. Smith

Table 10

(continued)

T. squamosa

SILVER B. amphitrite

T. squamosa

max.

nm

nm

nm

nm

18.2

min.

nm

nm

nm

nm

11.1

max.

3.3

min.

1.0

3.8

5.1 2.1 1.7 0.2

6.8 2.2 1.7 0.9

1.2

0.9 0.6

max.

nm

nm

nm

nm

4.3

min.

nm

nm

nm

nm

2.7

(Rainbow and Smith 1992). There remains a significant caveat however, for the Hong Kong data were collected in April of each year, not September as in this study. ANCOV A may have removed effects of size and, therefore, potentially some effects of age on metal concentration data, but it is quite probable that effects of season on accumulated metal concentrations are significant. Table 10 makes the comparison using standardsized bodies of B. amphitrite and T. squamosa, but confident conclusions concerning differences in the relative metal contaminations of Hong Kong and either Xiamen or Houzhu need to be based on large differences in accumulated metal concentrations. When considering Table 10 it is also necessary to remember that the two barnacles occupy different habitats, B. amphitrite occurring in more contaminated locations than T. squamosa which prefers wave action or at least strong tidal currents. Table 10, nevertheless, suggests that there were hotspots in Hong Kong for contamination by zinc, copper, lead and chromium, exceeding contamination levels at any of the sites inspected in Fujian. The use in this study of Balanus uliginosus as a biomonitor of heavy metals is novel. It has

25.4 13.1 15.8 7.8 1.7 0.9 1.1 0.4 9.9 1.9 6.1 1.2

proved to be an excellent biomonitor, highlighting intersite variation in bioavailabilities not identified by the other two species. B. uliginosus showed significant variation in accumulated concentrations of lead, chromium and silver. Interestingly, it was the only barnacle to accumulate measurable concentrations of nickel. B. uliginosus has, therefore, considerable potential as a biomonitor of contaminant metals in estuarine habitats in Southeast Asia. This study has also provided supporting evidence for the proposal by Phillips and Rainbow (1988) that Balanus amphitrite and Tetraclita squamosa are suitable metal biomonitors, worldwide in the case of the cosmopolitan former and throughout much of the Indo-Pacific for the latter.

Acknowledgements P.S.R. is grateful to Z.O. Huang for his hospitality in Xiamen. P.S.R. also thanks the Director and other staff of the Third Institute of Oceanography, Xiamen, particularly S.K. Yan for their assistance and co-operation in this project. It is a pleasure to acknowledge The Royal Society for travel funds for P.S.R. to visit China.

References Anderson, D.T. 1981. Cirral activity and feeding in the barnacle Balanus perforatus Bruguiere (Balanidae), with comments on the evolution 120

of feeding mechanisms in thoracic an cirripedes. Philosophical Transactions of the Royal Society of London B. 291: 411-49.

Metal biomonitoring in Xiamen

Chan, H.M., Rainbow, P.S. and Phillips, D.l.H. 1990. Barnacles ,and mussels as monitors of trace metal bio-availability in Hong Kong Waters. In The Marine Flora and Fauna of Hong Kong and Southern China II (ed. B. Morton), 1239-68. Proceedings of the Second International Marine Biological Workshop: The Marine Flora and Fauna of Hong Hong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. Crisp, D.l. and Southward, A.l. 1961. Different types of cirral activity of barnacles. Philosophical Transactions of the Royal Society of London B. 243: 271-308. Henry, D.P. and McLaughlin, P.A. 1975. The barnacles of the Balanus amphitrite complex (Cirripedia, Thoracica). Zoologische Verhandelingen, Leiden 141 :3-254. Hunt, M.l. and Alexander, C.G. 1991. Feeding mechanisms in the barnacle Tetraclita squamosa (Bruguiere). Journal of Experimental Marine Biology and Ecology 154:1-28. Lewis, l.A. 1985. A re-examination of Balanus variegatus Darwin (Cirripedia, Thoracica) from southern Australia. Crustaceana 48: 117-32. Luoma, S.N., Dagovitz, R. and Axtmann, E. 1990. Temporally intensive study of trace metals in sediments and bivalves from a large riverestuarine system: Suisun Bay/delta in San Francisco Bay. The Science of the Total Environment 97/98:685-712. Newman, W.A. and Ross, A. 1976. Revision of the balanomorph barnacles including a catalog of the species. San Diego Society of Natural History Memoir 9:1-108. Nugegoda, D. and Rainbow, P.S. 1989. Effects of salinity changes on zinc uptake and regulation by the decapod crustaceans Palaemon elegans and Palaemonetes varians. Marine Ecology

Progress Series 51 :57-75. Phillips, D.l.H. and Rainbow, P.S. 1988. Barnacles and mussels as biomonitors of trace elements: a comparative study. Marine Biology 49:83-93. Phillips, D.l.H. and Rainbow, P.S. 1993. Biomonitoring of Trace Aquatic Contaminants. London: Elsevier. Rainbow, P.S. 1987. Heavy metals in barnacles. In Barnacle Biology (ed. A.l. Southward), 405-17. Rotterdam: A.A. Balkema. Rainbow, P.S., Green, l. and Denny, P. 1989. A note on the intertidal ecology of two little known barnacles, Balanus kondakovi Tarasov and Zevina 1957, and Balanus patelliformis Bruguiere, 1789, from a Malaysian mangrove swamp (Cirripedia, Balanomorpha). Crustaceana 57:104-7. Rainbow, P.S. and Smith, B.D. 1992. Biomonitoring of Hong Kong coastal trace metals by barnacles, 1986-1989. In The Marine Flora and Fauna of Hong Kong and Southern China III (ed. B. Morton), 585-97. Proceedings of the Fourth International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. Hong Kong: Hong Kong University Press. Sunda, W.G., Engel, D.W. and Thuotte, R.M. 1978. Effect of chemical speciation on toxicity of cadmium to grass shrimp Palaemonetes pugio: importance of free cadmium ion. Environmental Science and Technology 12:409-13. Weeks, l.M. and Rainbow, P.S. 1991. The uptake and accumulation of zinc and copper from solution by two species of talitrid amphipods (Crustacea). Journal of the Marine Biological Association of the United Kingdom 71 :81126.

121

Asian Marine Biology 10 (1993): 123-132

LARVAL DEVELOPMENT OF EUPENTACTA FRAUDATRIX (HOLOTHUROIDEA, DENDROCHIROT A) Igor Vu. Dolmatov and V. V. Yushin Institute of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690032, Russia

Abstract Larval development of Eupentacta fraudatrix is examined. Cleavage is equal, holoblastic and leads to formation of a coeloblastula. Yolk granules are then released into the blastocoel. Within 24 hours embryos begin to swim slowly. At the beginning of day 2, the embryos are elongate and Vitellaria larvae are formed. Concurrently, gastrulation by invagination is started. On day 2-2.5 the transformation of the enterocoel occurs. It flattens and spreads around the gut and then divides into a hydrocoel and a somatocoel. A hydroporic canal grows out from the hydrocoel and opens externally by a hydropore. Ends of the hydrocoel fuse to form an ambulacral ring, the somatocoel divides longitudinally creating the left and right somatocoels. Definitive organogenesis is begun on days 2.5-3. Five tentacles, ambulacral canals and a polian vesicle are formed on the ambulacral ring. At this stage, the larvae settle. The anterior end of the gut and the ambulacral ring are shifted from the ventral side of the larva to the animal pole. Formation of the pentactula is completed on days 10-11.

Introduction The holothurian Eupentacta (= Cucumaria) fraudatrix (Djakonov and Baranova) is an important component of the benthos of the coastal zone of the Sea of Japan. Nonetheless, there is no information about the development of this holothurian. Formation of the coeloms, metamorphosis and definitive organogenesis have not been described. One of the reasons for this paucity of knowledge is that a considerable yolk content makes the larva opaque and does not permit direct observations on the development of the internal organs and metamorphosis. In connection with this, histological methods were used in the present work. The internal structure at different developmental stages and definitive organogenesis were studied using semi-thin sections of the larvae embedded in epoxy resin.

Materials and methods Spawning in Eupentacta fraudatrix occurs during the second half of summer. At this time of the year

the animals placed in glass aquaria often spawn spontaneously. Mature adult individuals were collected from Possjet Bay, Sea of Japan, in late August 1989. After spawning, fertilized eggs were placed in glass vessels with aerated seawater in which their development proceeded. Larvae were maintained at 15-17°C. At different developmental stages, larvae were fixed for 24 h at 4°C with 2% glutaraldehyde diluted with seawater. The animals were then rinsed in seawater and postfixed in 1% OS04. Larvae were dehydrated in ethyl alcohol and acetone series and embedded in a mixture of araldite and epone 812. Semi-thin sections cut on an Ultracut E (Reichert) ultratome were stained with methylene blue and mounted in araldite. The full series of transverse and longitudinal sections 0.7 to 1.0 J.U1l thick were studied and photographed with a Polyvar (Reichert) light microscope.

Results Cleavage Eggs are large, isolecithal, rich in yolk and

LV. Oolmatov

&

V.V. Vushin

measu re 350 ~ in diameter (Drozdov and Kasyanov 1985). They are covered externally by a thin envelope which is transformed to a cuticle as the larva develops . Cleavage is equa l, holobla stic. The time interval between twO consecutive cleavages is about 30 min. Two hours after s pawning (the 16-bJaSlO mere stage). a blastula having two cavity openings at both poles forms. Within the next 2 hours (the 64blastomeres stage) the openings disappear. Cleavage resu lts in the formation of a spherical

Plate I.

124

coeloblastula (Plate lA). During the first twelve hours, the embryo lays on the bottom of the vessel. As it seen in semi-thin sections. the yolk granules from the blastomeres begin to ingress into the blastocoel (Plate 1B), which by the end of the first day of development has been filled with yolk. Within 24 hours of spawning, ci lia have developed on the apical surface of the blastomeres and the embryos rise to the water surface and begin to either swim slowly or revolve about their axes.

Eupentacta fraudatrix development on semi-thin sections . A, blastula; B, basal part of blastomeres: release of yolk granules into the blaslocoel ; e, longitudinal section of the gastrula; 0 , longitudinal section of the larva at the stage of separation of the enterocoel; scale bar: A,C, D - 100 ~m; B -20 ~m.

Larval development of Eupentacta

Vitellaria At the beginning of the second day of development, the embryo begins to stretch along the animal-vegetative axis. The animal part somewhat broadens and the vegetative one narrows, thus producing in 36 h an elongate dropshaped, evenly ciliated, vitellaria. By beating of the cilia, it can swim with the animal pole first or revolve about the longitudinal axis. Concurrent with modification of the shape, the internal organs start to form. The gastrula is formed by invagination, the blastopore being situated either on the vegetative pole or is slightly shifted ventrally (Plate IC, Fig. lA). Oastrulation is accompanied by formation of the mesenchyme from the vegetative pole and bottom of the archenteron. After the archenteron has reached about the mid-length of the larva, it is divided by a longitudinal fold into an enterocoel and a gut primordium (Plate ID, Fig. IB and C). The gut curves to the ventral side of the larva and the enterocoel lies above it. The ventral ectoderm thickens and then a shallow vestibulum forms (Fig. ID). During the first half of the third day of development the major events are related to the transformation of the enterocoel. First it gradually flattens and spreads around the gut (Fig. 1D and E). The place of fusion of the ends of the coelom is situated either on the future ventral side or is slightly shifted to the left. Then the enterocoel divides transversely into an anterior part (hydrocoel) and a posterior part. From the hydrocoel, which often has not fully separated from the enterocoel, towards the dorsal side of the larva, a hydroporic canal, which opens externally by a narrow slit-like hydropore, grows out (Fig. IF). The ends of the hydrocoel fuse to form an ambulacral ring which encircles the anterior part of the gut. After this, the posterior part of the enterocoel divides longitudinally resulting in the left and the right somatocoels. Concurrent with the transformation of the coeloms, the nervous system forms. The cellular layer underlying the ectoderm of the vestibulum sinks into the interior towards the ambulacral ring to form a nerve ring. A slit-like structure - the

epineural canal - appears on the external surface of the latter. The space between the nerve ring and the ectoderm of the vestibulum is filled with yolk granules. By the end of the described period (2.5 days), definitive organogenesis commences. Seven processes appear almost simultaneously on the ambulacral ring (Plate 2A, Fig. 10). Five of them are located in the future interradii and, directed ventrally, represent mesodermal parts of the tentacles. In the ventral radius, together with the nerve cord and epineural canal arising from the nerve ring, a ventral radial ambulacral canal originates (Plate 2B). It is located in the primary body cavity among yolk granules immediately beneath the gut. Near the vegetative pole, the end of the ambulacral canal bifurcates resulting in ambulacral feet (Plate 2C, Fig. 10). The polian vesicle forms either in the right or in the left ventro-Iateral interradii. It is located between the gut and one of the somatocoels (Plate 2A).

Pentactula The pentactula begins to form on the third day after fertilization. The mesodermal primordia of the tentacles come into contact with the ectoderm from which the external cover of the tentacles is formed (Plate 2A and B, Fig. IH). The tentacles assume the form of digital appendages capable of extending outside. At their tips, sensitive papillae are formed by thickening of the ectoderm. Radial ambulacral canals appear in the radii of the ambulacral ring. Initially, the dorso-Iateral canals form and later, in 1-2 days, the ventrolateral canals appear. Throughout the entire period of formation of the pentactula, the ventro-Iateral canals are less developed than the other three. At this stage the larvae settle. The are attached by the tentacles to the bottom of the vessel and also can move slowly with the aid of the tentacles. Within the following three days, the entire oral complex (tentacles, the nerve ring, the ambulacral circular canal and the anterior portion of the gut) has gradually shifted from the ventral side of the larva to the animal pole. The organs are thus located along the longitudinal axis and the animal acquires a radial symmetry. By the sixth day of development, the larva has 125

I.Y. Dolmatov & V.V. Yushin

AR

EN

-------G

T

AF

Fig. 1. A schematic representation of the coelom derivatives formation during development of Eupentacta fraudatrix. A, gastrulation; S, initiation of division of archenteron; e, formation of enterocoel and gut rudiment; D, initiation of spreading of the enterocoel around the gut; E, spreading of the enterocoel around the gut; F, separation of hydrocoel from the enterocoel; G,H, two stages of ambulacral system formation (somatocoels are not shown).

126

Larval development 01 Eupenlacts

, 8

Plate 11 . Eupent8ct8 (r8udatrix development on semi-thin sections. A, longitudinal section of the early pentactuta on the third day of development; B, tangential section of the early pentactula (third day); C, transverse section through the posterior part 01 the early pentactula (third day); D, transverse section through the anterior part of early pentactula on the sixth day of development, arrows indicate ambulacral canals; scale bar 100 J.l.m. 127

I.V. Dolmatov & V.V. Vushin

five well-developed tentacles and two ambulacral feet. The position of the tentacles and ambulacral canals relative to each other undergoes change. The dorsal and the right dorso-Iateral tentacles are connected to the right dorso-Iateral ambulacral canal, two ventral tentacles are connected to the ventral ambulacral canal, and the left dorso-Iateral tentacle is connected to the left dorso-Iateral canal. The ventro-Iateral ambulacral canals remain free of tentacles (Fig. 2). In some larvae, the arrangement of the tentacles is a mirror reflection of that described above. The somatocoels enlarge and fuse, establishing a secondary body cavity (Plate 2D). Yolk, whose amount is still considerable, is shifted to the periphery of the larva. Part of the yolk granules is located between the visceral parts of the somatocoels and the gut epithelium where haemal lacunae will be formed (Plate 3). Of the five ambulacra, the ventral has the greatest length and diameter. It extends between the parietal part of the somatocoel and yolk of the primary body cavity almost to the end of the animal body (Plates 2D and 3). Here, two canals of ambulacral feet arise. In the anterior portion of the ambulacrum, in the coelomic epithelium underlying the ambulacral canal, a longitudinal

muscle band appears. Two dorso-Iateral ambulacra are smaller in diameter and length. They reach to about the mid-body and are gradually reduced. The gut lengthens and assumes an S shape. It remains enclosed from both ends and we found only 6-day-old larvae with a formed anal opening. By the sixth day of development, the histogenesis of the body wall commences. A thin layer of fibrous connective tissue is produced beneath the cuticle and the ectoderm (Plates 2D and 3). The amount of intercellular substance also increases at the anterior end between the tentacles and the walls of the tentacles and the oesophagus begin to form. Simultaneously, calcification processes start. In the body wall, under the ectoderm, numerous lamelliform spicules develop. Later, on either the tenth or eleventh day of development, they cover almost the entire body of the pentactula, forming a protective sheath. At the base of the tentacles calcification also takes place, the connective tissue between the tentacles and ambulacral canals is calcified to become a calcareous peripharhyngeal ring. Formation of the pentactula is completed on the tenth or eleventh day of development with the appearance of the mouth and the anal opening (Fig. 3).

MV Fig. 2. A schematic representation of tentacles and radial ambulacral canal development in larvae of Eupentacta fraudatrix. 128

Larval development 01 Eupentacla

Plate Ill.

Eupentacta frauda trix. A transverse semi-thin section at the mid-body region of the early pentaclula (sixth day of development) , arrows indicate ambulacral canals; scale bar 100 ).1m.

Fig. 3. A schematic representation of a sagittal section of Eupentacta fraudatrix pentactula on the 1011th day of development.

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Discussion Analysis of the obtained material has shown that the larval development of Eupentacta Jraudatrix occurs in a manner typical of many holothurians. Despite the presence in the ooplasm of a large amount of yolk, cleavage is holoblastic and equal and results in a typical coeloblastula. Soon after the formation of the blastula, the blastocoel becomes filled with yolk granules which are released from the blastomeres. Such a process has not been earlier described for holothurians, however in some of them, for example Cucumaria elongata (Chia and Buchanan 1969), before gastrulation the blastocoel is filled with 'a blastocoel jelly'. It is also secreted by blastomeres. It is very likely that the substance termed 'a blastocoel jelly' is also yolk. Nyholm (1951) reported that yolk fills the blastocoel of the Labidoplax buskii. Nothing is known about the subsequent fate of the yolk material in development. The doliolaria of Cucumaria planci possessed oil droplets in the preoral lobe (Selenka 1876). The preoral lobe of C. elongate contains 'a blastocoel jelly' (Chia and Buchanan 1969). Results of our study suggest that during the development of the internal organs, the yolk granules are forced towards the body wall or into the interspace between the visceral parts of the somatocoels and the gut epithelium and serve for a long time as an endogenous source of nutrition. They can be found in tissues of the pentactula of Eupentacta Jraudatrix for as long as two months of development and in C. japonica for up to four months (unpublished data). Release of yolk from the blastodermal cells into the blastocoel is known for some other invertebrates, for example, the Pterobranchia (Dilly 1973). In general, the development of Eupentacta Jraudatrix is characterized by a shortened metamorphosis and lack of catastrophic transformations of the internal organs and tissues. The vitellaria is evenly ciliated, as in some members of the genus Cucumaria, (Newth 1916; Runnstrom and Runnstrom 1920; Smith 1962; Naidenko and Levin 1983). This larva is similar to a planula-like larva of the Pterobranchia (Stebbing 1970; Ivanova-Kazas 1978). Obviously, the lack of ciliary bands is a secondary 130

simplification due to the lecitotrophic development. The formation of the internal organs of the vitellaria proceeds intensively. After the separation of the enterocoel, the formation of the ambulacral system commences and by the time of settlement, the definitive organogenesis has been markedly advanced. The provisory organs with the exception of the ectodermal cilia and hydropore, do not actually form. Hence the development of Eupentacta Jraudatrix can be regarded as direct development, according to Smiley et al. (1991). The pentactula possesses five ambulacral canals, five primary tentacles, two ambulacral feet, a polian vesicle and a hydroporic canal. At this stage a three-armed symmetry is evident against the background of a five-armed symmetry. The primary tentacles connect with three radial ambulacral canals, namely the ventral and two dorsal ones (Fig. 2). These three canals are better developed and appear earlier than the two ventrolateral ones. Such a three-armed symmetry, according to Runnstrom (1928), repeats a threearmed stage in the evolution of the Echinodermata. The development of the coeloms in Eupentacta Jraudatrix takes the way typical of holothurians (Selenka 1876; Hyman 1955; Smith 1962; Ivanova-Kazas 1978; Drozdov et al. 1990; Malakhov and Cherkasova 1991). In some holothurians, there is pronounced asymmetry in the formation of the coeloms. Thus in Stichopus japonicus there are, initially, only the left somatocoel, while the right somatocoel forms later as the left somatocoel derivative (Drozdov et al. 1990; Malakhov and Cherkasova 1991). Such an asymmetry is absent in E. Jraudatrix because the enterocoel has completely grown around the gut before its split into the hydrocel and the somatocoels. This is probably accounted for by the simplified and relatively rapid development of E. Jraudatrix. A characteristic feature of Eupentacta Jraudatrix is that the mouth and anal opening in the settled larvae are formed very late. Soon after the completion of gastrulation, the blastopore is closed and the gut loses it connection with the ectoderm. The vestibule, though present, is not so well developed as in other holothurians

Larval development of Eupentacta

(Runnstrom and Runnstrom 1920; Smith 1962) and the anterior portions of the digestive system are formed by growth of the gut rather than by invagination of the ectoderm. The mouth and the anus break open only by the tenth or the eleventh days of development. Their late formation appears to be connected to the lecithotrophic type of development and a later start of functioning of the digestive system. It is likely that larvae start to feed after the yolk sources have been depleted. The nervous system of Eupentacta Jraudatrix is formed by division of the cellular layer of the vestibule into the epidermis and the nerve ring. Subsequently, the radial nerve cords grow out from the nerve ring. Neither radial cords, nor their epineural canals come into contact with the ectoderm. The cavity of the epineural canal of the nerve ring is formed by cavitation of the surface layer of nerve cells and then spreads into the radial canal (Plate 2B). This process in Stichopus californicus occurs in the same manner (Smiley 1986). Our observations on the formation of closed ambulacra in E. fraudatrix are consistent with the hypothesis of Smiley (1986) that holothurians and sea urchins have no common ancestors. Thus, there are few provisory structures in the development of Eupentacta fraudatrix. The pelagic larva is merely a formal indicator of the presence of metamorphosis in holothurians. Only definitive organs are formed by the vitellaria stage. Lecithotrophic development and a short residence in the water column lead to the greatly simplified pattern of individual development of E. fraudatrix. Metamorphosis is actually reduced to a shift of the anterior part of the gut and the future aquapharhyngeal complex from the ventral side of the larva to the animal pole which becomes the anterior end of the animal. Similarly, the development of the lecithotrophic larvae of the Crinoidea occurs by displacement of individual organs (Ivanova-Kazas 1978). Migration of the

internal organs complex may be characteristic of lecithotrophic development in echinoderms. Acknowledgements Appreciation is expressed to Prof. V.V. Malakhov and Prof. V.L. Kasyanov for helpful comments to improve the manuscript. We thank Dr V. Ivantey for technical assistance.

Abbreviations used in the plates and figures A AC AF AR BD C EC EN G H HC HL HY LD LV M MB MV N NC P PT RD RV S T V Y

Ambulacral ring Radial ambulacral canal Canal of ambulacral foot Archenteron Blastoderm Calcareous ring Epineural canal Enterocoel Gut Hydropore Hydroporic canal Haemal lacuna Hydrocoel Left-dorsal ambulacral canal Left-ventral ambulacral canal Mesenchymal cells Longitudinal muscle band Midventral ambulacral canal Nerve ring Ventral radial nerve cord Polian vesicle Papilla of tentacle Right-dorsal ambulacral canal Right-ventral ambulacral canal Somatocoel Tentacle Valve Yolk granules

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Drozdov, A.L. and Kasyanov, V.L. 1985. Size and form of gametes in echinoderms. Ontogenez 16:49-59. (In Russian) Drozdov, A.L., Kornienko, E.S. and Kruchkova, G.A. 1990. Oocyte maturation, development and metamorphosis in the far-eastern sea cucumber Stichopus japonicus. Biologiya morya 43-50. (In Russian) Hyman, L.H. 1955. Echinoderms, vol. 4, The Invertebrates. New York: McGraw-Hill. Ivanova-Kazas, O.M. 1978. Comparative Embryology of Invertebrates. Echinodemata and Hemichordata. Moscow: Nauka. (In Russian) Malakhov, V. V. and Cherkasova LV. 1991. The embryonal and early larval development of Stichopus japonicus var. armatus (Aspidochirota, Stichopodidae). Zoologitchesky Zhurnal 70:55-67. (In Russian) Naidenko, V.P. and Levin, V.S. 1983. Rearing of a commercial sea cucumber Cucumaria japonica in the laboratory. Biologiya morya 4:61-5. (In Russian) Newth, H. 1916. On the early development of Cucumaria. Proceedings of the Zoological Society of London 2:631-41. Nyholm, K.G. 1951. The development and larval

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