Possible ecological impacts caused by sea cage farm activities on surrounding coral reef ecosystem in nha trang bay, vietnam

MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY _ NGUYEN THU HIEN POSSIBLE ECOLOGICAL IMPACTS CAUSED BY SEA-CAGE FARM ACTIVITIES ON SURROUNDING CORAL REEF ECOSYSTEM IN NHA TRANG BAY, VIETNAM MASTER THESIS KHANH HOA – 2017 MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY _ NGUYEN THU HIEN POSSIBLE ECOLOGICAL IMPACTS CAUSED BY SEA-CAGE FARM ACTIVITIES ON SURROUNDING CORAL REEF ECOSYSTEM IN NHA TRANG BAY, VIETNAM MASTER THESIS Marine Ecosystem Management and Major: Climate Change 772/QD-DHNT, dated 20/9/2016 Topic allocation Decision: Decision on establishing the Committee: 01/06/2017 – 05/06/2017 Defense date: Suppervisors: Dr Nguyen Lam Anh Chairman: Associate Prof Ngo Dang Nghia Faculty of Gradute Studies: Faculty of Economics KHANH HOA – 2017 UNDERTAKING I undertake that the thesis entitled: “Possible ecological impacts caused by seacage farm activities on surrounding coral reef ecosystem in Nha Trang Bay, Vietnam” is my own work The work has not been presented elsewhere for assessment until the time this thesis is submitted Nha Trang, 03, May, 2017 (Signature and full name) Nguyen Thu Hien i ACKNOWLEDGMENT I wish to express my sincere appreciation to the following organizations and persons for their invaluable support, help and encouragement to me in conducting this study: The Norwegian Programme for Capacity Development in Higher Education and Research for Development (Noherd) for giving me the opportunity to study and conduct this master thesis on Marine Ecosystem based Management and Climate Change The Faculty of Economics and Institute of Marine science and Fishing Technonogy in Nha Trang University; Section of Marine Ecology, Institute of Oceanography of Nha Trang; Nha Trang Institute of Technology Research and Application for supporting facilities, materials, apparatuses, equipment for helping and giving best conditions for me to finish my thesis My special thanks go to Prof Sigurd Stefansson, Prof Henrik Glenner and Dr Lam Anh for the continuous support of my Master study and research, for their patience, motivation, enthusiasm, and immense knowledge Their guidance helped me in all the time of research and writing of this thesis To Dr Hoang Trung Du and Dr Pham Trung San for their guidance and invaluable suggestions, their support, encouragement and flexibility, often beyond his call of responsibility Furthermore, I wish to express my profound gratitude for their stimulating comments and discussions, their ability to positively give and receive information, their openness towards freedom of expression, choices and their monumental patience shown during the research program Actually, their enthusiasm and integral view on research has made such a deep impression on me To all members of Section of Marine Ecology, Institute of Oceanography of Nha Trang and my colleagues in Corrosion Research Department, Nha Trang Institute of Technology Research and Application for their cooperation, for all the kindness and friendship ii Last but not the least, I would like to thank my family: my parents, my husband and to my brothers and sisters for supporting me spiritually throughout writing this thesis Thank you! Nha Trang, 03, May, 2017 (Signature and full name) Nguyen Thu Hien iii TABLE OF CONTENTS UNDERTAKING i ACKNOWLEDGMENT ii TABLE OF CONTENTS iv LIST OF SYMBOLS vi LIST OF ABBREVIATION vii LIST OF TABLES viii LIST OF FIGURES ix ABSTRACT x INTRODUCTION Research objectives Research contents Hypotheses Research questions CHAPTER 1: LITERATURE REVIEW 1.1 OVERVIEW OF RESEARCH SITUATION ABROAD 1.1.1 Aquaculture activities 1.1.2 The impacts of aquaculture activities to environment and ecosystems 1.2 OVERVIEW OF DOMESTIC RESEARCH SITUATION 1.2.1 Aquaculture activities 1.2.1.1 Aquaculture operations in South Central coastal provinces 1.2.1.2 Aquaculture activities in Khanh Hoa province 10 1.2.2 The impacts of aquaculture activities to environment and ecosystems 16 1.3 THE IMPACTS OF EUTROPHICATION AND SEDIMENTATION ON CORAL REEF 18 1.4 CLIMATE CHANGE FROM THE PERSPECTIVE OF STUDYING THE ANTHROPOGENIC IMPACTS BY AQUACULTURE 20 CHAPTER MATERIALS AND METHODOLOGY 22 2.1 DATA SOURCE USED 22 2.2 SAMPLING STRATEGIES 22 iv 2.2.1 Study sites and sampling design 22 2.2.2 Sediment sampling 23 2.2.3 Conducting field experiments (coral cross-transplanted) 24 2.3 THE METHOD OF SAMPLES ANALYZED 25 2.3.1 Sediment samples 25 2.3.2 Coral samples analysis: 27 2.4 DATA PROCESSING METHODS 28 CHAPTER RESULTS AND DISCUSSION 29 3.1 THE ASSESSMENT OF EUTROPHICATION IN DIFFERENT SITES 29 3.2 SEDIMENT CHARACTERISTIC AND SEDIMENT QUALITY 32 3.4 FFIELD EXPERIMENT – CORAL TRANSPLANTATION 38 CHAPTER 4: CONCLUSION AND RECOMMENDATION 41 REFERENCES 43 APPENDICES v LIST OF SYMBOLS NT1, NT2, NT3: Near-field farming sites NT4, NT6: Mid-filed farming sites (1.2km from the breeding areas) NT5, NT7: Far-field farming sites M0: Weight of aluminum cup M1: Weight of sample and aluminum cup M2: Weight of samples and aluminum cup dried in an oven for 48 hours at 80oC M3: Weight of samples after mashed, restored in other aluminum cup M4: Weight of samples after burned at 550oC in hours ChA: Chlorophyll-a concentration, as µg/l aD%O: Oxygen as absolute % deviation from saturation L: The amount of Nitrogen or Phosporous discharged into the environment (kg/m2) P: Total production (kg/m2) Fc /FCR: Feed conversion ratio Cfeed: The content of N/P in feed (%) Cfish: The content of N/P in feed inside the lobster, fish meat (%) vi LIST OF ABBREVIATION IPCC: LC50: Intergovernmental Panel on Climate Change The lethal concentration required to kill 50% of the population NCAR: Anthropologists at National Center for Atmospheric Research AAA: American Anthropological Association DIN: Dissolved inorganic nitrogen DIP: Dissolved inorganic phosphorus VAST: VietNam Academy Of Science And Technology TOM: Total Organic Matter TOC: Total Organic Carbon GF/F: The grade of Whatman paper used for filting extremely fine precipitates such as protein, nucleic acids, or serum precipitates HOBO: The device used for measuring air temperature, relative humidity, dew point, rainfall, soil moisture, solar radiation, wind speed and direction, barometric pressure, and more TN: Total Nitrogen TP: Total Phosphorus CHNO-S: Elemental analyser for analyzing Carbon, Hydrogen, Nitrogen, Sulfur and Oxygen content TSM: TRIX: FCR: Total suspended matter Trophic Index Feed conversion ratio vii LIST OF TABLES Table 1.1: Production of main species groups of fish from marine and coastal aquaculture in 2014 Table 1.2: Current status of fisheries and aquaculture in the South Central Province from 2009 to 2013 Table 1.3: Current status of fisheries and aquaculture in Khanh Hoa Province from 2009 to 2014 10 Table 1.4 Summary of the commonly cultured species in Khanh Hoa Province 13 Table 1.5: The development of lobster farming in Nha Trang bay from 2005 to 2011 15 Table 3.1: The nutrient concentration in Nha Trang Bay in two sampling periods 29 Table 3.2: The Estimation of waste output from lobster cage farm activities in 2015 37 viii CHAPTER CONCLUSION AND RECOMMENDATION The TRIX indexes in both surface and bottom layers in Nha Trang Bay (ranging from 5-6) indicated that level of eutrophication of these water bodies were high and water quality was bad The N:P ratios at almost surveyed sites were greater than the Redfield ratio of 16:1 This shows that during the time of the research survey, phosphorus might probably be the limitation factor in these waters The high level of nutrient concentration deposited in bottom sediments and harmed to bottom fauna and flora At sites which are near the culture area (NT1, NT2, NT3) showed a higher value of TOM, TOC, TN and TP concentration than that figures in remote stations The further away from the farming area, the lower nutrient concentration was measured That means significant amount of excess food and feaces were released into water column beneath cages, affecting to sediment environment and increase of organic matter in quality of sediment However, the TOC (