ESTIMATING SUSTAINABLE HARVESTS
OF LAKE VICTORIA FISHERY
James Philbert Mpele1, Yaw Nkansah-Gyekye2, Oluwole Daniel Makinde2 1School of Computational and Communication Science and Engineering
The Nelson Mandela African Institution of Science and Technology (NM-AIST)
P.O. Box 447, Tengeru, Arusha, TANZANIA 2,3Faculty of Military Science
Stellenbosch University
Private Bag X2, Saldanha 7395, SOUTH AFRICA
Abstract. A study was conducted to develop an environmentally sound strategy for sustainable harvesting of fish species of the Lake Victoria fishery. Its objectives were: firstly, to estimate current harvesting rates of fish species; secondly to show how the biomass stock is changing in response to growth rates and harvesting rates; and finally, using a mathematical model, to predict sustainable levels of harvesting the fish species. Lake wide catch data from year 2005 to 2011 were used for various fish species and were analyzed using Least square method with the aid of MAPLE. Harvesting efforts were computed; 0.2805 for the Nile perch representing a maximum sustainable harvest of 74412.8447 tonnes per year; 0.0593 for the Nile tilapia representing a maximum sustainable harvest of 4834.4503 tonnes per year; 0.5334 for the small pelagic silver fish representing 259538.9165 tonnes per year; 0.1158 for the Haplochromines representing a maximum sustainable harvest of 12569.7240 tonnes per year and 0.0108 for the other fish species representing a maximum sustainable harvest of 87.1936 tonnes per year. Further the study revealed that the lake Victoria fishery is yet sustainable however its sustanability is under 50% for most of fish species.
AMS Subject classification: 65P99, 92B05, 37N25
Keywords and phrases: lake Victoria fishery, harvesting efforts, sustainable harvests, carrying capacity, growth rates, maximum sustainable yield, steady states
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DOI: 10.12732/ijam.v27i4.7
Volume: 27
Issue: 4
Year: 2014