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Apeldoorn, Netherlands

van der Knaap M.,Maxillion Consultancy | Ligtvoet W.,Netherlands Environmental Assessment Agency
Aquatic Ecosystem Health and Management | Year: 2010

The exploitation of Nile perch resources of Lake Victoria has strongly increased during recent years. This is apparent from decreasing catch rates and ever increasing numbers of fishermen, fishing craft and gears. Despite this, it remains economic to continue the exploitation and exportation of Nile perch products. Exports to the EU, however, seemed to have reached their maximum in 2003, which could have been due to competition from cheaper fish products from certain Asian countries, as well as to market diversification by the East African exporting firms. Fish prices paid to fishermen increased over time as a result of the success of the Nile perch fishery. However, the increased influx of money into the fishing communities did not necessarily lead to a reduction in poverty. This could be due to the lack of saving and investment possibilities. In the absence of sufficient schooling, youths automatically enter the fishery sector and as a result of relatively low investment costs and high earnings the fishing effort will continue to increase until the open-access based management regime is replaced by a licensing system. The role that Beach Management Units can play in managing the human and fisheries resources will have to be strengthened. It is concluded that the economic gains based on the new fishery, in itself proved to be insufficient to provide a structural sustainable development, due to the restricted social and institutional capacity which hampers the riparian population's ability to adapt to the new social and fishery challenges. © 2010 AEHMS. Source

Njiru M.,Moi University | Mkumbo O.C.,Lake Victoria Fisheries Organisation LVFO | van der Knaap M.,Maxillion Consultancy
Aquatic Ecosystem Health and Management | Year: 2010

The decline in fish species in Lake Victoria is one of the largest documented losses of biodiversity in an ecosystem. The reduction in species in the lake was attributed to overexploitation through increased fishing capacity, use of illegal fishing gears and poor enforcement of regulations. Introduction of the predatory Nile perch is blamed for the decline of the native species, especially the haplochromine cichlids. The native tilapiines, Oreochromis esculentus and Oreochromis variabilis, declined due to hybridization and competition with the introduced Oreochromis niloticus. Diversity loss in haplochromine cichlids has also been attributed to hybridisation caused by increased water turbidity, which reduces visibility in recognising conspecifics during breeding. Degradation of the environment through poor farming patterns and waste disposal has led to increased nutrients into the lake, in turn leading to changes in water quality, increased algal blooms and subsequent anoxia which led to frequent fish kills in the 1990s. However, recent resurgence of haplochromines thought to be extinct, disputes the fact that extinction of several species occurred. Though not denying that a drastic reduction in the number of native species occurred, the much hyped extinction could be a result of a lack of adequate information on taxonomy and ecology of the haplochromines as well. © 2010 AEHMS. Source

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