Distribution, Status, and some aspects of the Biology of two Non- Cichlid Native Fishes of Lake Victoria, Kenya

Abstract

The status, distribution and some aspects of the breeding biology of mormyrids and Brycinus sp. was studied in the years 2000 and 2001 in the Kenyan portion of Lake Victoria. Five mormyrid species, Mormyrus kanume FORSK., Pollimyrus nigricans BLGR., Marcusenius victoriae WORTH. Hippopotamyrus grahami NORM., and Gnathonemus longibarbis HILG., and two species of Brycinus, Brycinus Jacksonii BLGR and B. sadleri BLGR. were recorded. M. kannume and B. sadleri occurred both at the river mouths and in the open waters while the rest of the species were restricted to certain river mouths only. The size distribution of these species in the lake consists of mainly larger ripe individuals. Of the mormyrids P. nigricans dominated with 62% while M. kannume accounted for <5% of the mormyrids caught. The size range for each species caught, size at first maturity for both males and females and sex ratios are presented. The Possible reasons for the decline of the species numbers and abundance are suggested