Prediction of Maximum Sustainable Yield and Optimum Fishing Effort for the Nile Perch (Lates Lates niloticus L.) in Lake Chamo, Ethiopia

Buchale Shishitu Shija

Abstract


The study was conducted to assess the current status and determine the maximum sustainable yield level of exploitation for the Nile perch ( (Lates niloticus L., 1758) a stock in Lake Chamo, Ethiopia. Data were collected from eight major landing sites of Lake Chamo for three days in a week for ten months (February to November, 2018). The total length, sample weight and total weight of L. niloticus caught by the fishers and an the fishing efforts were the basic information collected from these sites. Totally, 544 L. niloticus samples were collected in 120 days. Jones length based cohort analysis model and length length-based based Thompson and Bell yield prediction models were employed to estimate the maximum sustainable yield. Overall about 0.25 million L. niloticus populations were estimated to exist in the lake. The estimated current annual yield was 102.4 tons per year. However, the predicted value of MSY was 74 tons obtained at f MSY of 9,007 nets. The maturity length (L 50 ) was 100 cm and out of the total annual catches 87.9% of L. niloticus were below their respective size of maturity. Thus, the reduction of yield was due to experiencing both growth and recruitment overfishing with increased eased effort and reduced mesh size. Lates niloticus of Lake Chamo is overfished. . Therefore, conservation and rehabilitation as well as co-management management practices are required for sustainable utilization of the resource.

Keywords


Jones length based cohort analysis model, Lake Chamo, stock assessment, yield prediction

Full Text:

PDF HTML

References


Ayenew, T., and Legesse, D. (2007). The changing face of the Ethiopian rift lakes and their environs: call of the time. Lakes & Reservoirs: Research and Management.12: 149 –165. https://doi.org/10.1111/j.1440-1770.2007.00332.x

Bekele, S. (2006).Abaya-Chamo Lakes physical and water resources characteristics, including scenarios and impacts. International Water Management Institute. http://www.uni-siegen.de/fb10/fwu/ww/publikationen/volume0607.

Belay, A., and Wood, R.B. (1982). Liminological aspect of algal bloom on Lake Chamo in Gemu Gofa Administrative region on Ethiopia in 1978. SINET: Ethiopian Journal of Science. 5:1-19.

Cushing, D.H. (1982). Climate and fisheries. Academic Press, London-New York, pp. 273.

Dadebo, E., Ingemar, A., and Gunnel, A. (2005). Maturation, sex ratio and fecundity of the Nile perch Lates niloticus (L.) (Pisces: Centropomidae) in Lake Chamo, Ethiopia. Ethiopian Journal of Science. 28(2):151–160.

Dejene, Z. (2008). Impact of fisheries and water quality changes on the management of Lake Chamo, Ethiopia . M.Sc. thesis, Addis Ababa University, Addis Ababa, Ethiopia.

FAO (2003). Fishery and aquaculture country profiles. Ethiopia, Country profile fact sheets. FAO fisheries and aquaculture department [online]. Rome. Updated 1 January 2003. [http://www.fao.org/fishery/facp/ETH/en

Gulland, J.A. (1971). The fish resources of the Oceans. Fishing News for the Food and Agriculture Organization (Vol. 97, pp. 255).The University of Virginia.

Israel, and Banzon (2000). Over fishing in the Philippine Marine Fisheries Sector. International Development Research Centre, Ottawa, Canada.

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, (Vol. 256, pp. 118). Food and Agriculture Organization of the United Nations, the University of Virginia.

Kebede, E. (1996). Phytoplankton in an alkalinity-salinity series of Lakes in the Ethiopian Rift Valley. PhD thesis, Uppsala University, Sweden.

LFDP (1997). Lake management plans. Lake fisheries development project, phase II, Working Paper 23. 2 nd ed. Ministry of Agriculture, Addis Ababa.

Mulugeta, B., and Mereke, K. (2016). Prediction of yield and optimum fishing effort for the Nile perch (Lates niloticus) stock of Lake Chamo, Ethiopia. International Journal of Fisheries and Aquatic Studies. 4(2): 433-436.

Pauly, D. (1980). On the interrelationships between natural mortality, growth parameters and mean environmental temperature in 175 fish stocks. Journal of conservation, CIEM. 39(2): 175-192.

Pauly, D. (1987). A Review of the ELEFAN System for Analysis of Length-Frequency Data in Fish and Aquatic Invertebrates. In: Pauly, D. and Morgan, G.R.(Ed.). Proceedings of 13th conference on“Length-Based Methods in Fisheries Research”, International Center for Living Aquatic Resources Management, Manila, Philippines.pp. 468.

Pauly, D., and Morgan, G.R. (1987). Length based methods in fisheries research. Proceedings of International Conference on the “Theory and Application of Length-Based Methods for Stock Assessment” 11-16 February, Institute for Scientific Research, Safat, Kuwait. pp.468.

Schnute, J. (1987). A general fishery model for a size- structured fish population. Canadian Journal of Fisheries and Aquatic Science. 44 (5): 924-940.

Sparre P, Venema, S.C. (1992). Introduction to tropical fish stock assessment.FAO Fisheries Technical manual. 306(1):376.

Tekle-Giorgis, Y.(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 (Lakes Awassa, Abaya and Chamo), Ethiopia. PhD thesis, Addis Ababa University, Ethiopia.

Thopson, W.F, and Bell, F.H. (1934). Biological statistics of the pacific halibut fishery.Effects of changes in intensity upon total yield and yield per unit of gear. http://docs.streamnetlibrary.org/IPHC/Report0012.pdf.

Tudorancea, C., and Taylor, W.D. (2002). Ethiopian rift valley lakes. African Journal of Aquatic Science. 28(1): 289.

Ward, A., and Wakayo, T. (2013). Final Technical Report: Provision of Technical Assistance to review and improve the catch and effort data recording system (CEDRS) and deliver basic training in stock assessment in Ethiopia.159 pp.

Wetherall, J.A., Polovina, J.J., and Ralston, S. (1987). Estimating growth and mortality in steady-state fish stocks from length-frequency data in Pauly, D. and G.R. Morgan (eds.). Proceedings of 13th ICLARM conference on Length-based methods in fisheries research Institute for Scientific Research, Safat, and Kuwait.pp.53–74.


Refbacks

  • There are currently no refbacks.


Copyright (c) 2020 Journal of Agriculture and Environmental Sciences

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.