Observations on the benthos of Murchison Bay, Lake Victoria, East Africa

Abstract

There is paucity of data on benthic organisms in Lake Victoria, as in many other African lakes. A study to ascertain the biomass, standing crop and spatial distribution of benthic organism in the northern shores of lake Victoria indicated a rich benthic fauna composed mainly of insects, molluscs and oligochaetes. Total biomass for the 200 km2 Murchison Bay was 146,000 tonnes. The lamellibranchsformed the highest biomass (68,940 t) fol1owed by gastropods (30,840 t), insects (25,760 t) and annelids (20,460 t). Mean standing crop biomass values for genera in the various taxa were determined from their spatial distribution patterns (mean numbers per unit area) and mean individual weights. The high benthic biomass is currently under-utilized by benthic organisms at higher trophic levels and consequently represents utilizable organic matter directly or indirectly for man’s benefit. Hence, a lakewide study is recommended.