MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY MAXIMUM SUSTAINABLE YIELD ASSESSMENT IN NUI COC RESERVOIR By: Mrs Stéphanie KAMONDO Nha Trang University, Khanh Hoa province Master Thesis July, 2014 MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY MAXIMUM SUSTAINABLE YIELD ASSESSMENT IN NUI COC RESERVOIR Thesis submitted in fulfillment of the requirements for the award of Master of Science in Aquaculture By: Mrs Stéphanie KAMONDO 54CH347 Nha Trang University, Khanh Hoa province First Supervisor: Dr Anh T Bui, Ministry of Agriculture and Rural Development, Vietnam Second Supervisor: Prof Sena S De Silva, Deakin University, Australia July, 2014 CANDIDATE DECLARATION I certify that the thesis entitled “MAXIMUM SUSTAINABLE YIELD ASSESSMENT IN NUI COC RESERVOIR” submitted for the degree of Master of Science in Aquaculture is the result of my own work and that where reference is made to the work of others, due acknowledgment is given I also certify that any material in the thesis which has been accepted for a degree or a diploma by any University or Institution is identified in the text Full Name: Stéphanie KAMONDO Signed ……………………………… Date: i i ACKNOWLEDGEMENTS First and above all, I praise God, the Almighty for providing me this opportunity and granting me the capability to proceed successfully This is a great opportunity to express my gratitude to my first supervisor Dr Anh Bui The for making this research possible His support, guidance and advice throughout the research project as well as his painstaking effort in proof reading the drafts, are greatly appreciated Indeed, without his guidance, I would not be able to put the topic together My special and heartily thanks to my second supervisor Professor Sena De Silva for his support and suggestions I gratefully acknowledge the financial support I received from the Government of Rwanda through the Ministry of Agriculture and Animal Resources under the Rwanda Agriculture Board I also thank the Vietnamese technical team for their support and valuable recommendations to the former PAIGELAC /RAB To Nha Trang University, I extend my gratitude for the academic and technical support beyond giving me the opportunity to pursue my studies Especially, I would like to thank the Director of Aquaculture Institute, Dr Pham Quoc Hung for his support and collaboration A special acknowledgement goes to the Research Institute for Aquaculture No.1, particularly to Dr Nguyen Van Tien, Mr Nguyen Duc Tuan and Mrs Nguyen Thi Hoa for their kindness, friendship, guidance and support The library facilities, office, internet access as well as accommodation have been indispensable Acknowledgements to the people in Nui Coc Fishery Station for their collaboration, particularly Mr Le Quy Hung (the Director) and Mr Pham The Hoang (Accountant) I would like to thank my adorable husband Irenée NIYIBIZI for his love, understanding and personal support at all times The great patience, assistance and encouragement shown by my father Faustin RWAMFIZI NYANGEZI during these ii two years are greatly appreciated My lovely children, mother, brothers, sisters and brother in law have given me their equivocal support throughout, as always, for which my mere expression of thanks likewise does not suffice Last but not least, many thanks to my classmates, all friends and relatives, your friendship and encouragements were a real support during this period iii ABSTRACT Nui Coc Reservoir was constructed to be used mainly for two purposes: to control flooding and to irrigate 11,500 of agriculture land and industrial zone The latter was recognized by the Government of Vietnam as an important provider of animal protein and employment opportunities for people living in its vicinity However as in many other Vietnamese reservoirs, the biodiversity of fish fauna is deteriorating There is a decline of economically significant species in number and production The aim of this study was to collate available fisheries data such as catch data, fishing effort, CPUE, fishing gear and estimate the Maximum Sustainable Yield (MSY) for better management strategies in the future This thesis research also attempted to estimate the stocking efficiency in the water body Through primary and secondary data collection, catch assessment based on catch and effort data was the main approach used to achieve the mentioned objectives MSY of two different periods (P1 and P2) were estimated applying Schaefer model A gradual decline in fish production trend during a twenty two-year period (19782010) was observed due to some interactions factors and inappropriate/poor management of the reservoir Two main fishing seasons (March-July and September-November) were detected and this is related to the water level fluctuations and the type of fishing gear used in Nui Coc reservoir Stocking activity as a cost effective strategy was found to have significant impact on fish yield when implemented on a regular basis However a number of factors should be taken into consideration to optimize fish yield Some management strategies such as fishery regulation and regular stocking activities are given as recommendations for long-term sustainability of the water body resources iv TABLE OF CONTENTS ACKNOWLEDGEMENTS i ABSTRACT iii TABLE OF CONTENTS iv LIST OF TABLES vi LIST OF FIGURES vii ABBREVIATIONS ix INTRODUCTION CHAPTER 1- LITERATURE REVIEW 1.1 Overview on world inland fisheries 1.2 Reservoir fisheries in the world 1.2.1 Overview on reservoir fisheries resources 1.2.2 Reservoirs classification 1.2.3 Fish production in reservoirs 1.2.3.1 Phase 1- Early growth production 1.2.3.2 Phase 2- Stabilization 10 1.2.3.3 Phase 3- Sustainable production 11 1.3 Reservoir fisheries in Vietnam 12 1.3.1 Water resources in Vietnam 12 1.3.2 Reservoir fisheries development in Vietnam 14 1.3.3 Reservoir fisheries management in Vietnam 15 1.3.3.1 Government line management 16 1.3.3.1.1 Indirect GoV management 16 1.3.3.1.2 Provincial management 16 1.3.3.1.3 Enterprise licensing management 17 1.3.3.1.4 Open access 17 1.3.3.2 Co-operative line management 17 1.3.3.3 Private sector line management 18 CHAPTER 2- METHODOLOGY 19 2.1 Study area 19 2.2.1 The fishery 21 2.2.2 Fish yield 21 2.2.3 Historical development of Nui Coc fisheries 22 2.2.3.1 Progression period - State subsidies (1976 – 1985) 22 2.2.3.2 Recession period (1986 – 1990) 22 2.2.3.3 Improvement period (1990 – 2000) 23 2.3 Data collection 24 Delet v 2.4 Fishing gear 25 2.5 Fishing effort 27 2.6 Catch per Unit of Effort 27 2.7 Estimation Production (Y) 28 2.8 Maximum Sustainable Yield (MSY) 28 2.8.1 Standardization of effort 29 2.8.2 Relationship of stocking density to fish yield 30 2.9 Data analysis 30 CHAPTER 3- RESULTS AND DISCUSSION 32 3.1 Current fisheries management system in Nui Coc Reservoir 33 3.2 Fish production and MSY (relative CPUE and relative effort) 34 3.3 Fishing seasons 39 3.4 CPUE and effort by gear 43 3.5 Stocking efficiency 48 CHAPTER 4- CONCLUSION AND RECOMMENDATIONS 52 4.1 Conclusion 52 4.2 Recommendations 52 APPENDICES 62 vi LIST OF TABLES Table 1.1 World capture fisheries production in 2011 and 2012 (using data from [16]) Table 1.2 Inland capture fisheries: Top ten producers in the world [16] Table 1.3 Records on large reservoirs by regions [20] Table 1.4 Inland water bodies of Vietnam [39] 12 Table 1.5 General status of reservoir fisheries in Vietnam in 1993 [44] 13 Table 2.1 Some physical and chemical features of Nui Coc Reservoir [6] 20 Table 2.2 Fingerling stocked and fish production in Nui Coc Reservoir from 1978 to 2000 [10] 23 Table 2.3 Summary of the features of the main types of gear used and the species of fish caught in Nui Coc Reservoir: 26 Table 2.4 Unit effort of fishing gear used in Nui Coc Reservoir 27 Table 3.1 Relationships between the relative CPUE and total yield to the relative effort 37 Table 3.2 Relationship between fishing effort and CPUE for different fishing gears in Nui Coc Reservoir 43 vii LIST OF FIGURES Figure 1.1 World capture fisheries production in 2011 and 2012 (using data from [16]) Figure 1.2 Records on large reservoirs by regions [using data from 20] Figure 1.3 The representation of the fish productivity changes 11 Figure 1.4 Reservoir fisheries productivity by regions in Vietnam in 1993 (using data from [44]) 13 Figure 2.1 Map of Nui coc reservoir showing its location (Source: Google map data 2014) 19 Figure 2.2 Nui coc reservoir photograph showing the study area 19 Figure 2.3 Fluctuation in water level of Nui Coc Reservoir in 1999 [10] 20 Figure 2.4 Fishing gear utilization [using data from 42, 48-50] 21 Figure 2.5 Yearly fish productivity (kg/ha) in Nui Coc Reservoir in the period of 1978 - 2003 [10, 48, 50] 22 Figure 3.1 Schematic representation of the current Nui Coc Reservoir fisheries management structure (Thai Nguyen province) 34 Figure 3.2 Variation of the Fish production during 1978 to 2010 period 35 Figure 3.3 The relationship between the relative effort (100 m2 of net used) and the total yield (kg) for the period of 2001-2003 36 Figure 3.4 The relationship between the relative effort (100 m2 of net used) and the total yield (kg) for the period of 2006-2008 36 Figure 3.5 The relationship between the relative effort (100 m2 of net used) and the CPUE (kg per 100 m2 of net used ) for the period of 2006-2008 37 Figure 3.6 Monthly changes in fish yield using gill net during the period P1 (20012003) 40 Figure 3.7 Monthly changes in fish yield using gill net during the period P2 (20062008) 40 Figure 3.8 Monthly changes in fish yield using covert net during the period P1 (2001-2003) 40 55 10 Bui, T.A., Preliminary results of the fishery in Nui Cocreservoir, Thai Nguyen Province., 2001, University of Fisheries,: Nhatrang, Vietnam p 52 pages 11 FAO, Inland Fisheries.FAO Technical Guidelines for Responsible Fisheries No FAO 1997 No 6: p 1-34 pages 12 Beard Jr, T.D., et al., Ecosystem approach to inland fisheries: research needs and implementation 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Environment, Deakin University, Warrnambool Campus, Princes Highway, Warrnambool, Victoria 3280, Australia p 1-23 73 De Silva, S.S and S.J Funge-Smith, A review of stock enhancement practices in the inland water fisheries of Asia Asia-Pacific Fishery Commission, Bangkok, Thailand Vol RAP Publication No 2005/12, 93 p 2005 74 Viet, T.T., et al An Assessment of the Fisheries of Four Stocked Reservoirs in the Central Highlands of Vietnam In: Reservoir and Culture-Based Fisheries: Biology and Management in Proceedings of an International Workshop 2001 Bangkok, Thailand: Australian Centre for International Agricultural Research 62 APPENDICES Appendix I Summary on different reservoir fisheries management structures (Notes: In-GoM: Indirect Government Management; Pro-M: Provincial Management; En-LiM: Enterprise Licensing Management; OA: Open Access; [6]) Reservoir fisheries management structures Characteristics Government line Co-operative line In-GoM Owner Reservoir area Pro-M En-LiM Fishery OA The GoV(via Provincial MoF) control Fishery enterprise enterprise control Large-sized Large and Large and Medium-sized medium-sized Structure of the Oriented on system management and Private sector GoV authorities A group of members Private & PGO managed waters Medium-sized medium-sized Medium and small-sized Managed cooperatively based on their abilities administration Strategies on the GoV system subsidization Using period No limit Gov subsidization Self supplying Nothing Pay levy to PGO No limit No limit Certain period (5-7 yrs) No limit Certain period 63 Appendix II Schematic representation of Nui Coc reservoir fisheries management structure (Thai Nguyen province) [6] ARD BANK THAI NGUYEN PROVINCIAL GOVERNMENT (Agriculture and Rural Development Bank) THAI NGUYEN ARD BANK OF DARD THAI NGUYEN Loans IRRIGATION UNIT AGRICULTURE EXTENSION UNIT FISHERIES UNIT AGRICULTURE & IRRIGATION Co Ltd Supports & funds Technical supports Data Management COMMUNES In conjunction with DARD units (fisheries, extension) HATCHERY Loans NUI COC FISH FARM GUARDS REGISTRATION Issues daily Stocking Feedback licenses FISHERS NUI COC RESERVOIR MARKETS Daily surveillance 64 Appendix III Fish species caught in Nui Coc Reservoir [6, 10] No Family name Species name Adrianichthyidae Pelteobagrus fulvidraco Bagridae Oreochromis niloticus niloticus Cyprinidae Aristichthys nobilis Carassius auratus auratus Cirrhinus cirrhosus Cirrhinus molitorella Ctenopharyngodon idella Culter erythropterus Cyprinus carpio carpio Erythroculter hypselonotus Labeo rohita Garra orientalis Hemiculter leucisculus Hypophthalmichthys harmandi Hypophthalmichthys molitrix Pseudohemiculter dispar Puntius semifasciolatus Rasborinus lineatus Xenocypris argentea Gobiidae Glossogobius giuris Rhinogobius giurinus Rhinogobius leavelli 65 Appendix IV Fish Production and yield in Nui Coc Reservoir from 1978 to 2010 Year Fish Production (Metric Tons) Number of fingerlings stocked /ha Yield (Kg/ha) 1978 47 1880 18.8 1979 112 1980 44.8 1980 95 930 38 1981 118 2220 47.2 1982 110 2950 44 1983 122.5 2500 49 1984 100 2000 40 1985 90 1000 36 1986 95 650 38 1987 97 360 38.8 1988 56 320 22.4 1989 33 360 13.2 1990 12 150 4.8 1991 30 12 1992 45 18 1993 40 16 1994 30 12 1995 25 10 1996 32 300 12.8 1997 30 200 12 1998 51.7 100 26.36 1999 45.9 100 18.36 66 2000 42.6 100 17.04 2001 39.6 204 15.84 2002 14 401 5.59 2003 200 3.11 2004 - - 2005 - - 2006 27.3 10.94 2007 27 460 10.82 2008 21 612.3 8.46 2009 27.41 692.46 10.96 2010 28.05 - 11.22 67 Appendix V Stocking density, fish yield in year n, n+1 and n+2 using data of 1978 to 2009 Year Stocking Density Yield (kg/ha) in year n Yield (kg/ha) in year n+1 Yield (kg/ha) in year n+2 1978 752 18 44.8 38 1979 792 44.8 38 47.2 1980 372 38 47.2 44 1981 888 47.2 44 49 1982 1180 44 49 40 1983 1000 49 40 36 1984 800 40 36 38 1985 400 36 38 38.8 1986 260 38 38.8 22.4 1987 144 38.8 22.4 13.2 1988 128 22.4 13.2 4.8 1989 144 13.2 4.8 12 1990 60 4.8 12 18 1991 - 12 18 16 1992 - 18 16 12 1993 - 16 12 10 1994 - 12 10 12.8 1995 - 10 12.8 12 1996 120 12.8 12 20.68 1997 80 12 20.68 18.36 1998 40 20.68 18.36 17.04 1999 40 18.36 17.04 15.84 2000 40 17.04 15.84 5.6 68 2001 81.6 15.84 5.6 3.2 2002 160.4 5.6 3.2 - 2003 80 3.2 - - 2004 - - - 10.92 2005 - - 10.92 10.8 2006 - 10.92 10.8 8.4 2007 184 10.8 8.4 10.964 2008 244.92 8.4 10.964 2009 276.984 10.964 69 Appendix VI Some field trip photographs [...]... fishing gear, gill net and seine net in units of 100m net used per day, covert net and trammel net in unit of 100m2 per day in the period of 2006-2008 46 Figure 3.17 The relationship between the number of fingerlings stocked and the catch in Nui Coc Reservoir from 1978 to 2009 49 Figure 3.18 The relationship of the fish yield in year n, n+1, n+2 and stocking density in year n in Nui Coc Reservoir. .. and the maximum yield of 2, 480 t occurred in the ninth year The catch landing of the Bhumipol Reservoir increased from 583 t in the second year to 1,089 t in the third year after the closure of the Bhumipol dam [34] Fish yield of Rihand Reservoir in India reached its peak in the fourth year of impondment [35] Annual fish landing from Gandhi Sagar Reservoir also in India reached its first peak in the... Co-operative line management This management approach is observed in some medium and small reservoirs such Phu Ninh Reservoir in Quang Nam Province where small groups form a unit to run the business including stocking, harvesting and marketing activities They work together in planning, investing and share responsibilities and income but they have to pay the levy to PGO 18 1.3.3.3 Private sector line management... in Nui Coc Reservoir in the period of 1978 - 2003 [10, 48, 50] 2.2.3 Historical development of Nui Coc fisheries As in many other Vietnamese reservoirs, the fisheries development in Nui Coc Reservoir is divided in three periods [10] 2.2.3.1 Progression period - State subsidies (1976 – 1985) During this period, the Nui Coc fishery company which was established in 1976 by the national government during... annual stocking rate was 2 046 500 fingerlings of 3 - 4 cm and this resulted in annual catch of 200 – 290 t Similar situations are known for other reservoirs such as Nui Coc and Suoi Hai In the case of Nui Coc reservoir, the annual catch for 1978 – 83 was 100 – 120 t when about 400 0000 fingerlings of 9 – 12 were stocked annually and a dramatic decline in catch in the reservoir has occurred since 1991... existing reservoirs in Vietnam is deteriorating A decline in the number and production of economically significant species has been recognized in most reservoirs throughout the country including Nui Coc reservoir [5, 6] Nguyen [9] noted that 70-75% of fish production in north and central Vietnam was fish of low value [5] At the same time, lack of systematic information on fisheries data from Nui Coc reservoir. .. make the reservoir suitable for aquaculture [47] Figure 2.1 Map of Nui coc reservoir showing its location (Source: Google map data 2014) Figure 2.2 Nui coc reservoir photograph showing the study area 20 Figure 2.3 Fluctuation in water level of Nui Coc Reservoir in 1999 [10] Table 2.1 Some physical and chemical features of Nui Coc Reservoir [6] No Physical and chemical features Value 1 River basin Red... but the maximum yield of the 697 t of fish was obtained in the 13th year after the closure of the dam [36] Sarnita [37] reported that fish yields in reservoirs in Indonesia reached their peaks during the first several years of impoundment He pointed out that maximum catch was recorded in the fourth year after impoundment in Jatiluhur, the ninth year in lake Darma and twelfth year in lake Rawa Pening 1.2.3.2... Figure 3.9 Monthly changes in fish yield using covert net during the period P2 (2006-2008) 40 Figure 3.10 Monthly changes in fish yield using trammel net during the period P1 (2001-2003) 41 Figure 3.11 Monthly changes in fish yield using trammel net during the period P2 (2006-2008) 41 Figure 3.12 Monthly changes in fish yield using seine net during the period P1 (2001-2003)... for resettling displaced persons particularly exemplified in the case of Saguling and Jatinuhur reservoirs in Indonesia [4] The current number of reservoirs in Vietnam is much higher than in the past because many new reservoirs have been constructed [5], with about more than 6000 reservoirs built in recent years (information provided by Directorate of Irrigation, 2014) Most of reservoirs in Vietnam