Oliva C. Mkumbo
TAFIRI, Mwanza, Tanzania.

The future of the Nile perch fishery has always been a concern for all the stakeholders and even more to scientists working on the Lake. A continuos decrease in catch per unit of effort is recorded over the years since the establishment of that fishery in mid 1980s. The same decreasing trend in mean length is shown by length frequency data recorded by three different research vessels, as well as data from the artisanal fishery

Growth parameters of Nile perch in the lake have been estimated both by Acere (1985), Asila & Ogari, (1990) and Ligtvoet & Mkumbo (1988). These values will be compared with estimates from the research vessel data of 1996 and 1997. Length at first maturity will also be calculated and later compared from that available in FishBase. Optimum length at capture (Lopt.) will be calculated by taking 61% of the length infinite. These parameters will then be used to assess whether the stock is overfished and what type of overfishing. The impact of the overfishing in terms of economic value will also be calculated.