Mesozooplankton Community Structure: Its Seasonal Shifts, Grazing and Growth Potential in the Bay of Bengal -60 -30 0 30 60 0-40 40-200 200-300 300-500 500-1000 0-MLD TT-BT BT-300 m 300-500 m 500-1000 m 9 11 13 15 17 19 ■ 0-MLD ■ TT-BT ❑ 200- 300 • 300- 500 ■ 500- 1000 H' CBI CB2 CB3 CB4 CBS Thesis submitted to Goa University for the degree of 'Doctor of Philosophy in-Marine Sciences Veronica Fernandes National Institute of Oceanography Council of Scientific and Industrial Research Dona Paula, Goa- 403 004, India June 2008 CERTIFICATE This is to certify that Ms. Veronica Fernandes has duly completed the thesis entitled `Mesozooplankton community Structure: Its seasonal shifts, grazing and growth potential in the Bay of Bengal ' under my supervision for the award of the degree of Doctor of Philosophy. This thesis being submitted to the Goa University, Taleigao Plateau, Goa for the award of the degree of Doctor of Philosophy in Marine Sciences is based on original studies carried out by her. The thesis or any part thereof has not been previously submitted for any other degree or diploma in any Universities or Institutions. N. Ramaiah Research Guide Scientist Date: June 16, 2008 National Institute of Oceanography Place: Dona Paula Dona Paula, Goa-403 004 -44 jr- yikazit N t e. \, t' P1114 /414 o , 77 Ko-ce'dP 578 F EA/ e--5 4ci 2 DECLARATION As required under the University Ordinance 0.19.8 (iv), I hereby declare that the present thesis entitled `Mesozooplankton community structure: Its seasonal shifts, grazing and growth potential in the Bay of Bengal ' is my original work carried out in the National Institute of Oceanography, Dona-Paula, Goa and the same has not been submitted in part or in full elsewhere for any other degree or diploma. To the best of my knowledge, the present research is the first comprehensive work of its kind from the area studied. Veronica Fernandes ACKNOWLEDGEMENT I express my deep sense of gratitude and sincere thanks to my research guide Dr. N. Ramaiah, Scientist, National Institute of Oceanography, Goa, for his continuous support and encouragement throughout my research tenure. I also gratefully thank him for critically reviewing the thesis work. His broad understanding of science, scientific experience and consideration for perfection has helped in completing this piece of work. I thank the former director Dr. E. Desa for giving me an opportunity to be associated with this institute. I also thank Dr. S. R. Shetye, Director, National Institute of Oceanography for the necessary laboratory facilities. I take this opportunity to thank Late Dr. M. Madhupratap- Coordinator-Bay of Bengal Process Studies (From 2002-2004) who has inspired me to take up this interesting subject of research for doctoral studies. I thank Dr. K. Althaff and his students for their patience in teaching me the basics of copepodology and identification techniques. I also thank Dr. R. Stephen for training me in copepod identification. I thank Dr. Conway and Dr. Achuthankutty for organizing the zooplankton identification workshop that has gone a long way in sharpening my zooplankton identification skills. I __e this opportunity to Dr. S. Prasannakumar- Coordinator- Bay of Bengal Process Studies (from 2004- 2007) for providing the physical oceanography data that has been used in this thesis and also for encouragement. I acknowledge Dr. S. Sardessai for providing the chemical data that has been used in this thesis. I also take this opportunity to thank Dr. N. B. Bhosle for his encouragement especially towards writing and publishing more papers. I express my sincere thanks to Dr. M. P. Tapaswi, Librarian, and his staff for their efficient support in procuring the literature and maintaining the best of oceanography journals. I also acknowledge the help rendered for all the HRDG work provided by Dr. V. K. Banakar. I thank Dr. G.N. Nayak, Head, Department of Marine Science, my co-guide for support and guidance in my work. I take this opportunity to thank the members of the FRC panel for their critical and valuable reviews. Thanks also to my VC's nominee Dr. P.A. Lokabharathi for the suggestions provided in helping me to make this thesis better. I thank the DOD, for providing financial assistance while working in the DOD funded Bay of Bengal Process Studies (BOBPS) project. I also acknowledge CSIR for an award of Senior Research Fellowship that has helped me to carry out this thesis work to completion. I thank Drs. Manguesh Gauns, Godhantaraman N.(Madras University), Madhu N. V (RC-Kochi), Jyothibabu (RC-Kochi) and P. V Bhaskar for their help and goodwill during various stages of my career. I also thank my oldest colleague Mrs Jane T. Paul with whom I worked in the first project when I joined NIO. With a large life-experience that she used to always share and, tough-to-approach shell but a soft core, she was a great company in my research career. I thank my colleagues, Veera Victoria Rodrigues, Sanjay Kumar Singh, Sagar Nayak, Abdulsalam A.S. Alkawri, Venecia Catul for being around in a team spirit, helpful, understanding each other and living in the lab like 'its our own home' attitude. I also thank Mrs. Sujata Kurtarkar for the help rendered. Thanks are also due to Jasmine, Muraleedharan, Pramod and Martin from Kochi RC, for helping me during the experiments on board. For all help rendered at different stages of the experiments during the cruise a special thanks to all crew of FORV Sagar Sampada (cruise no SS-240). I further acknowledge the support of the crew members of ORV Sagar Kanya (SK182 and 191). Thanks to all the BOBPS team members. I take this time to acknowledge the ITG group for their instant efforts to attend to any of my pc complaints. I also thank my friends Jayu Narvekar and Ranjita Harji for whatever help rendered during my research career. I am deeply indebted to my husband Remy, without his co-operation and constant support, it would have been difficult for me to attain this target. Here, I also would like to mention my sincere thanks to my parents, who always wanted me to achieve great heights in my educational career and, my in-laws who believed and were very supportive in all that I did. I also thank my other family members and well-wishers who were always concerned for my work and me. Last but not the least; I thank GOD, Almighty, for being with me unfailingly, for his constant grace, mercy, love and umpteen blessings that He has provided me. Veronica Fernandes Dedicated - To 9frly Beloved - Parents Table of Contents Page No. Chapter 1 Introduction 1-11 Chapter 2 Review of Literature 12-27 Chapter 3 General Hydrography and Distribution of Chlorophyll a 28-41 Chapter 4 Different Groups of Mesozooplankton from Central Bay 42-54 Chapter 5 Different Groups of Mesozooplankton from Western Bay 55-69 Chapter 6 Copepoda in Central Bay of Bengal 70-95 Chapter 7 Copepoda in Western Bay of Bengal 96-111 Chapter 8 Vital Rates of Copepods in the Bay 112-136 Chapter 9 Summary 137-142 References 143-175 Publications 176 Number of Tables 57 Number of Figures 64 Number of Plates 8 Chapter 1 Chapter 1 Introduction Ocean biology is complex, profound and, enigmatic. With all its forms known to mankind, life exists from the 'skin' [surface micro-layer] to the deepest zones of the marine domain. Ocean thus is the cradle of wide spectrum of organisms ranging from teeming, tiny autotrophic phytoplankton to heterotrophic bacteria; and from microfauna to fish to macrofauna including the gigantic whales. Victor Hensen (1887) coined the term "plankton" for all those organisms drifting in the water and those unable to move against the currents. The animal constituent of the plankton is known as zooplankton. Some of these are herbivorous, carnivorous, detritivorous or omnivorous (Metz and Schnack-Schiel 1995). Some foraminiferans, radiolarians and also some metazoans (cnidarians and mollusks) are mixotrophic, the combination of auto- and heterotrophy (Tittel et al. 2003). Some calanoids and cyclopoids are known to be coprophagous, feeding on zooplankton feces (Noji et al. 1991; Gonzales et al.1994). Depending on the lifetime spent in the planktonic form, zooplankton are either holoplanktonic, spending their entire life in plankton or meroplanktonic, drifting as plankton only for a part of their life before becoming benthic or nektonic (Martin et al. 1996, 1997). Foraminifers, radiolarians, siphonophores, ctenophores, pelagic polychaetes, heteropods, pteropods, ostracods, copepods with few exceptions, hyperiids, euphausiids, most chaetognaths, appendicularians and salps are holoplanktonic. Examples of meroplankton are larvae of cephalopods and fish that become part of nekton when adult. Cladocerans and some copepods produce resting eggs that are part of benthos during unfavorable conditions (Weider et al. 1997; Blumenshine et al. 2000). Hydrozoans and scyphozoans alternate between the planktic medusae during summer and benthic polyp stage during winter (Hartwick 1991). Also, larvae of benthic polychaetes, mollusks, echinoderms, barnacles and decapods are seen in the plankton for a short span of time (Raymont 1983). Animal phyla normally encountered in plankton are listed in Table 1.1. 1 1.1. Significance of Zooplankton In aquatic ecosystems, zooplankton form an important link between primary and tertiary level in the food chain leading to the production of fishery. About 90% of the world's fisheries occur in rich coastal areas, where dense populations of plankton grow (O'Driscoll 2000). It has been well established that potentials of pelagic fishes viz. fin fishes; crustaceans, mollusks and marine mammals either directly or indirectly depend on zooplankton (Arai 1988; Ates 1988; Harbison 1993; Plounevez and Champalbert 2000; Dalpadado et al.