A total of 457 hauls were taken during experimental bottom trawl surveys in the Uganda
sector of Lake Victoria between November 1997 and June 1999 to estimate composition,
distribution and abundance of the major fish species in waters 4-60 m deep. Fifteen fish groups
were caught with Nile perch, Lates niloticus (L.), constituting 94% by weight. Haplochromines and
L. niloticus occurred in all areas sampled, while Nile tilapia, Oreochromis niloticus (L.) and other
tilapiines were restricted to waters <30 m deep. The mean trawl catch rate in the zone where
artisanal fishermen operate (i.e. in waters <30m depth was 165 kg hr1, of which 93.6% comprised L. niloticus. Species diversity and relative abundance decreased with increasing water depth.