Abstract

The Sondu-Miriu Hydroelectric Power Project (SMHPP) is a run-of-the-river hydro-power project on the Sondu-Miriu River, Kenya. The part of the river studied: between the Sondu Bridge upstream, and Osodo Bay on L. Victoria, was divided into three zones; 1. Upstream of the dam, artificial lake approximately 5 km long; 15 – 2 km wide, 2. Depleted section and, 3. Lower section. SMHPP caused part of river below the dam (depleted section) to reduce in volume during power generation. Since inception, construction and implementation of the project, concerns were raised that the project would result in loss of Labeo and Synodontisfishes which were singled out as most vulnerable. This investigation set to determine the effects of SMHPP on river’s fishes; and focused on species diversity, abundance and distribution. An electrofisher was used in sampling. The data obtained was compared with those reported earlier, particularly a single previous report based on electrofishing. Fish biomasses were: Upper zone 4,583 g, depleted zone, 10,666 g and lower zone, 22,004 g respectively, with a total biomass of 37,253 g from fishing activity lasting for 429 min. Catch-effort data for each zone; types, numbers and weights are given, compared and discussed. Diversity was highest, Simpson’s Diversity Index was 12.945 in the upper zone.

Key words: Sondu-Miriu, hydropower project, electrofishing, fish diversity, river zones, fishing.