Some Aspects of Fish Biology and Ecology of River Perkerra in Lake Baringo Basin, Kenya

Abstract

Human activities including construction of dams along the river ecosystems may result in ecological changes in the fish and fisheries. This study assessed some aspects of fish biology and ecology of River Perkerra in Lake Baringo basin, Kenya. Fish species, abundance and distribution, food and feeding habits, maturity stages, growth, length-weight relationships, and sex ratio were the main parameters determined along the river profile earmarked as Chemasus (upstream), Ravine Kabarnet (Mid-stream) and Marigat Embarkment (Downstream) stations. The physico-chemical parameters showed significant spatial variation in relation to the prevailing human activities within the catchment. Chemusus station had the highest DO, TDS and pH, whereas lower reaches in Marigat embarkment had the highest phosphates values than other sites. Two species ( Labeobarbus altenialis and Labeo cylindricus) were identified hence poor fish diversity in River Perkerra. The mean length of L. altenialis was higher at Ravine Kabarnet than at Marigat embarkment but the weights showed inverse relationships. Many species’ diet consisted of insect remains, plant materials, detritus, plant remains, algae where the stomach fullness for most fish was 0.5 and 0.75. The two species were classified as omnivorous but to a larger extent, very opportunistic. Sampled fish exhibited negative allometric growth (b<3) which is reminiscent of poor growth conditions. Variations in fish community attributes were associated with longitudinal anthropogenic, physiological, biological and environmental factors. Sex ratios of fish in the river indicated that more females occurred than males. The vast majority of fish species were in stage III and IV. Management of River Perkerra fisheries requires to set aside a single economic vision of the resource use moving to an ecosystem-oriented approach that incorporate, among other components, the hydrological regime, species life history traits, fishing impacts on other species, and main stakeholders’ socioeconomic requirements as key elements for the preservation of fishery sustainability