Seaweed farming and artisanal fisheries in an Indonesian seagrass bed – Complementary or competitive usages? Sven Uli Blankenhorn Vorgelegt im Fachbereich 2 (Biologie/Chemie) der Universität Bremen als Dissertation zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) Alfred Wegener Institute for Polar- and Marine Research Wadden Sea Station Sylt Seaweed farming and artisanal fisheries in an Indonesian seagrass bed – Complementary or competitive usages? submitted by Sven Uli Blankenhorn in partial fulfilment of the requirements for the degree of Doctor of Natural Sciences (Dr. rer. nat.) Faculty 2 Biology / Chemistry University Bremen June 2007 Gutachter der Dissertation: Prof. Dr. W. Arntz, AWI Bremerhaven / Universität Bremen Dr. H. Asmus, AWI Wattenmeerstation Sylt Tag des öffentlichen Kolloquiums: 13.07.2007 SPICE – Science for the Protection of Indonesian Coastal Ecosystems This thesis is part of the SPICE (Science for the Protection of Indonesian Coastal Ecosys- tems) program, Cluster 1: Coral Reef Based Ecosystems, founded by the BmB+F (German federal ministry for education and research). Additional funding was provided by the DAAD (German Academic Exchange Service). „Kalau tidak ada rumput laut Puntondo mati.” “Without seaweed Puntondo would be dead.” Daeng Laga, village chief of Puntondo previous page: Satellite image of the western part of Laikang Bay, South Sulawesi, Indonesia. Puntondo on the small peninsula extending into the bay. Source: GoogleEarth Disclaimer Herewith I assure that I wrote this thesis independently and that I did not use any additional help except to the extend and the manner stated. References are cited in compliance with guidelines on safeguarding good scientific practice. Bremen, June 4th 2007 Sven Blankenhorn CONTENTS Contents ACKNOWLEDGEMENTS ............................................................................................................................................ viii SUMMARY .................................................................................................................................................................. ix ZUSAMMENFASSUNG................................................................................................................................................. xi RINGKASAN ...............................................................................................................................................................xiii GENERAL INTRODUCTION........................................................................................................................................... 1 The seagrass environment 1 Mediation of oceanographic parameters 2 Enrichment of coastal biodiversity 3 Human influences 4 Seaweed farming 5 Culture of carrageenophytes in South-East Asia 5 Farming methods 6 Effects on the environment 10 Artisanal fisheries 10 Fisheries management 11 Marine protected areas and alternative livelihoods 11 Traditional knowledge 12 Aims of the thesis 12 Socio-economic aspects of seaweed farming 12 Long-term effects of seaweed farming on seagrass beds 13 Economically important fish species, methods and fishing habitats 13 Fish stocks and gill net fishery in seagrass beds 13 Seagrass beds as a common resource for seaweed farming and fisheries 14 RESULTS OF THE THESIS............................................................................................................................................. 15 Socio-economic aspects of seaweed farming 15 Long-term effects of seaweed farming on seagrass beds 15 Economically important fish species, methods and fishing habitats 16 Fish stocks and gill net fishery in seagrass beds 17 GENERAL DISCUSSION .............................................................................................................................................. 19 Sustainability of seaweed farming 19 Sustainability of artisanal fisheries 20 Seagrass beds as a common resource for seaweed farming and fisheries 20 Seaweed farming as an alternative livelihood 21 References 22 v CONTENTS CHAPTER 1 SEAWEED FARMING IN TRADITIONAL FISHING VILLAGES: AN EXAMPLE FROM SOUTH SULAWESI, INDONESIA......................................................................... 34 Abstract 34 Keywords 34 Introduction 34 Methods 35 Results 36 Economic activities and effort 37 Seaweed culture and fishing problems 39 Market problems and income 39 Satisfaction with seaweed farming and fisheries, hopes for the future 40 Discussion 41 Economic activities and effort 41 Seaweed culture and fishing problems 43 Market problems and income 44 Satisfaction with seaweed farming and fisheries, hopes for the future 45 Conclusion 45 Acknowledgements 46 References 46 CHAPTER 2 LONG-TERM EFFECTS OF FLOATING LONG-LINE SEAWEED FARMING ON SEAGRASS SHOOT DENSITY AND BIOMASS................................................................................. 50 Abstract 50 Keywords 50 Introduction 51 Methods 52 Study area 52 Experimental design 53 Field sampling and laboratory analysis 54 Statistical analysis 54 Results 55 Shoot density 55 Biomass 57 Discussion 59 Shoot density 59 Biomass 60 Conclusion and recommendation 62 Acknowledgements 63 References 63 Appendix 66 CHAPTER 3 FISHERMEN’S PERCEPTION OF ARTISANAL FISHERIES AND IMPLICATIONS FOR MANAGEMENT IN A BAY IN SOUTH SULAWESI, INDONESIA ............................. 73 Abstract 73 Keywords 73 Introduction 73 vi CONTENTS Methods 75 Study area 75 Community surveys 76 Literature data 76 Statistical analysis 76 Results 77 Fished species and local names 77 Used gear, catch habitat and abundance 77 Fish sizes 83 Average and maximum length at site compared to literature data 83 Market prices and economical value 84 Assessment of food items, trophic levels, and habitats 86 Discussion 88 Fished species and local names 88 Used gear, catch habitat and abundance 88 Fish sizes 90 Average and maximum length at site compared to literature data 90 Assessment of food items, trophic levels, and habitats 90 Market prices and economical value 91 Conclusion and recommendation 92 Acknowledgements 93 References 93 CHAPTER 4 VARIATIONS IN FISH STOCKS AND ARTISANAL GILL NET FISHERY IN AN INDONESIAN SEAGRASS BED.................................................................................................. 98 Abstract 98 Keywords 98 Introduction 98 Methods 100 Study site 100 Sampling strategy and measured parameters 101 Statistical analysis 102 Results 103 General catch characteristics 103 Diurnal fluctuations 106 Lunar fluctuations 106 Seasonal fluctuations 107 Discussion 110 General catch characteristics 111 Diurnal fluctuations 112 Lunar fluctuations 113 Seasonal fluctuations 113 Conclusion 114 Acknowledgements 114 References 115 vii CONTENTS Acknowledgements I would like to thank my first supervisor Prof. Dr. Wolf Arntz for his willingness to supervise this thesis despite of his more than busy schedule. My second supervisor Dr. Harald Asmus is thanked for supporting my research ideas. He gave me great freedom in every way to plan and conduct my field research, which was highly appreciated. The warm welcome at the AWI Wadden Sea Station by Dr. Ragnhild Asmus, Dr. Patrick Polte, and Dr. Anja Schanz was very pleasurable. Birgit Hussel is thanked for help in the laboratory and organizing shippment of scientific equipment.During her stay in Indonesia Andrea Bäurle made the days in the lab much more fun. Dominik Kneer, Hung Liu, and Pe- ter Schauerte were great friends during their time in Indonesia. At UNHAS in Makassar Prof. Dr. Ambo Tuwo at the Faculty of Oceanography and Fisher- ies and Dr. Jamaluddin Jompa at the CCRR provided valuable help in organizing the stay at their institution. Especially Dr. Magdalena Litaay is thanked for dealing with day-to-day problems and making many, many calls to keep things running. Dodi Priosambodo’s help in correcting my Indonesian writing not only in this thesis was highly appreciated. Mastar, Pak Ridwan, Ulla, and many others helped in many ways to organize the research. At the ZMT in Bremen Dr. Eberhard Krain has to be thanked for his invaluable efforts dealing with visa and customs officials. Prof. Dr. Venugopalan Ittekkot and Dr. Claudio Rich- ter were irreplaceable in planning and running the SPICE program and cluster 1, respec- tively. The discussions with Esther Borell and Leyla Knittweis were very fruitful and will not be forgotten. In Puntondo, without the support by PPLH-Puntondo, especially Daeng Laga, Beatrix, Wajib, Yuli, and Yeny my research would not have been possible. LIPI in Jakarta, and espe- cially Pak Ruben, is thanked for issuing a research permit. The DAAD scholarship for the first 18 months of my stay in Indonesia was of great help. My friends in Germany, especially Florian, Matthias and his wife Martina, Roland and his wife Mamisolo, and Steffen always welcomed me very warmly during my few stays, it felt as if I never had been away. In Makassar, Adi, Edi, Ningsih, and Ema were great fun. Without the support of my parents during long years in school, university and Indonesia I would not have succeeded. They gave me the independence I needed do to my thesis under conditions which were challenging. My brother Kai and his girlfriend Eri often enough were very competent and ready to help with computer problems. Without my girlfriend Titi it would have suffered from serious depressions and with her childish (in the best possible meaning) ways she understood to cheer me up and to forget about the daily chaos. viii