Agriculture, Forestry and Fisheries
Volume 5, Issue 4, August 2016, Pages: 97-107
Received: Sep. 1, 2015;
Accepted: Sep. 16, 2015;
Published: Jul. 18, 2016
Views 4114 Downloads 197
Negese Kebtieneh, Department of Wildlife, Wetland and Fishery Management, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Shashemene, Ethiopia
Yitayal Alemu, Department of Wildlife, Wetland and Fishery Management, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Shashemene, Ethiopia
Mulugeta Tesfa, Department of Wildlife, Wetland and Fishery Management, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Shashemene, Ethiopia
The study was conducted on Lake Hawassa, one of the series Ethiopian rift valleys lakes. Data were collected from the area where fish are landed at one major landing site called fish market informally known as Amora Gedel, for one year (365days) on a daily basis. The length composition of tilapia caught by the fishery, total tilapia yield, fishing effort expanded as well as the price of tilapia and the cost of fishing operation were the basic information collected from the site. The aim of the analysis was to assess sustainability of fish stock, fishing level and to predict optimum yield and the bio-economic features of Lake Hawassa fisheries. Jones length based cohort analysis Model and length-based Thompson and Bell yield Prediction Model have been employed to estimate the maximum sustainable yield and maximum economic yield with their corresponding effort level. The estimated current annual yield was 182.94 tons of tilapia with the annual sale value of 4,158,760 ETB and 3,199,210 ETB of net profit for the fishermen cooperative. The predicted value of MSY was 186.72 tons/yr and this is obtained at fishing mortality factor of 1.6. And also MEY was 178.20 tons/yr and this is obtained at fishing mortality factor of 0.8. The fishery sector was found inefficient; the production was below its maximum sustainable yield level. Therefore harvest level should increase to its maximum sustainable yield level this might be possible by reducing the operating cost in order to increase both the level of yield as well as the net profit gained by the fishery sector.
Stock Assessment and Estimation of Maximum Sustainable Yield for Tilapia Stock (Oriocromis niloticus) in Lake Hawassa, Ethiopia, Agriculture, Forestry and Fisheries.
Vol. 5, No. 4,
2016, pp. 97-107.
MacLean, J. A. and Evans, D. O. 1981. The stock concept, discreteness of fish stocks and fisheries management. Canadian Journal of Fisheries and Aquatic Sciences, 38: 1889-1898.
FAO. 2010. The State of World Fisheries and Aquaculture 2010: FAO, Fisheries and Aquaculture Department. Vialedelle Terme di Caracalla, 00153 Rome, Italy.
Alverson, D. L. and Dunlop, K. 1998. Status of World Marine Fish Stocks: Fisheries Research Institute, School of Fisheries, University of Washington Seattle, November 1998. Washington 98195.
Sarnowski, V. A. 2004. The Artisanal Fisheries of Lake Albert and the Problem of Overfishing. Conference on International Agricultural Research for Development. Geographisches Institut, Johannes Gutenberg Universität Mainz, 55099 Mainz, October 5-7, 2004. Berlin, Germany
LFDP. 1997. Lake management plans. Lake Fisheries Development Project, Phase II, Working Paper 23. 2nd ed. Ministry of Agriculture, Addis Ababa.
FAO. 2000. The State of World Fisheries and Aquaculture 2000: FAO, Fisheries and Aquaculture Department. Vialedelle Terme di Caracalla, 00153 Rome, Italy.
FAO. 2009a. The State of World Fisheries and Aquaculture 2008: FAO, Fisheries and Aquaculture Department. Vialedelle Terme di Caracalla, 00153 Rome, Italy.
FAO. 2009b. Factors of unsustainability and over exploitation in marine fisheries views from the southern Mediterranean, West Africa, Southeast Asia and the Caribbean. FAO Fisheries and Aquaculture Circular No. 1037. Vialedelle Terme di Caracalla, 00153 Rome, Italy
Pauly, D. 1984a. Length converted catch curves. A powerful tool for fisheries research in the tropics (Part II). ICLARM Fishbyte, 2 (1): 17-19
Sparre, P. and Venema, S. C. 1992. Introduction to tropical fish stock assessment. Part 1. Manual. FAO Fisheries Technical Paper No. 306.1, 376 p.
Yosef T-G. 1990. Age determination and growth estimation of immature Oreochromis niloticus Pisces: Cichlidae) in Lake Awassa, Ethiopia MSc thesis University of Waterloo, Waterloo, Canada.
Yosef T-G. 2002. Comparative age and growth assessment of the African catfish, Clarias gariepinus Burchell (Clariidae) and, Nile perch, Lates niloticus, Linn (Centropomidae) in the three southern Rift Valley lakes of Ethiopia (Lakes Awassa, Abaya and Chamo). PhD thesis Addis Ababa University, 160 p.
Demeke, A. 1998. Age and growth determination of Ttilapia, Oreochromisniloticus L. (Pisces: Cichlidae) in some lakes in Ethiopia. Ph. D. thesis, Addis Ababa University, Ethiopia. 115 p.
Thompson, W. F. and Bell, F. H. 1934. Biological statistics of the pacific halibut fishery. 2. Effects of changes in intensity upon total yield and yield per unit of gear. Report of the international Fisheries (Pacific halibut) Commission, 8: 49 p.
Pauly, D. and Morgan, G. R. 1987. Length based methods in fisheries research. ICLARM Conference proceedings, 13: 468 p.
Schnute, J. 1987. A general fishery model for a size- structured fish population. Canadian Journal of Fisheries and Aquatic Science, 44 (5): 924-940.
Meagrey, B. A. 1989. Review and comparison of age-structured stock assessment models from theoretical and applied points of view. American Fisheries Society Symposium, 6: 8-48.
Venema, S. C. Christensen, J. M. and Pauly, D. 1988. Training in tropical fish stock assessment: a narrative of experience. FAO Fisheries Technical Paper, (389): 1-15p.
Sparre, P. and Willmann, R. 1992. Computer programs for bio-economic analysis of fisheries. BEAMR manual. Analytical bio-economic simulation of space structured multi species and multi-fleet fisheries. FAO Computerized Information Series (Fisheries) (3): 248 p.
Reyntjens, D. and Tesfaye, W. 1998. Fisheries management – a review of the current status and research needs in Ethiopia. SINET: Ethiopian Journal of Science, 21 (2) 231-266.
Jones, R. 1984. Assessing the effects of changes in exploitation patterns using length composition data (with notes on VPA and Cohort analysis). FAO Fisheries Technical Paper, 256: 118 p.