Impact of Fishing on the Inshore Fishery of Lake Victoria (East Africa)

Abstract

The inshore fishery of Lake Victoria has symptoms of severe overfishing. Curvilinear multiple regression analysis was used to examine the large variation in fishing effort, gear composition, and catches around the lake and suggest fishing practices that would give highest yields. The overfishing problem is due to the kind of gear in use and not to excessive fishing per se. Heavy fishing is often associated with the use of small mesh gillnets and seines to catch small fish such as Haplochromis, a practice that does not seem to justify the damage done to catches of the larger species by the same gear. The best strategy for maximizing the total tonnage yield is to fish optimally for the herbivorous genus Tilapia. This means using only the larger gillnets appropriate for Tilapia, as well as hooks, both at a very high fishing effort. The hooks capture large predators such as Bagrus, Clarias, and Protopterus, an abundant resource in themselves, and simultaneously appear to increase Tilapia yields indirectly by reducing losses of Tilapia to predators. Key words: Lake Victoria, ecosystem, succession, multispecies fishery, multigear fishery, fish yield, Africa, lake, lungfish, Tilapia, Haplochromis, catfish