The Dynamics of Selected Limnological Data Along a Land Use Gradient in River Molo, Kenya
Rivers provide a suite of ecosystem goods and services to fisheries, as well as water that benefit the domestic and industrial use of the riparian communities. The increasing intensification of human activities along River Molo in the Rift Valley, Kenya continues to affect the diversity of aquatic life including fish. Whereas, information on the status and changes in fish population and ecological attributes along the river is fundamental, knowledge is currently lacking. The study evaluated the status of R. Molo fisheries and the environmental conditions longitudinally along the river. All the physicochemical water quality parameters demonstrated significant (P < 0.05) spatial variations in the sampled stations of R. Molo. There were 54 different species of algae identified in this study and the average algal density fluctuated between 2 to 16 cells ml-1. There were also, significant differences in the occurrence of macroinvertebrate among sites (Chi-square; 2 = 20.1121, df = 3, P = 0.0031). There was a significant difference in the fish catch data based on the sampling location and fish species (P < 0.05). The minimum sizes at which the species mature differed with species. Of all the species sampled, only Labeo cylindricus exhibited a positive allometric growth (b < 3). Variations in limnology attributes of R. Molo were associated with longitudinal anthropogenic activities. Consequently, the need for R. Molo watershed management plan with a single economic vision of the resource use based on an ecosystem approach cannot be overstated. The plan should capture among other components, the hydrological regime, and species life history traits, fishing impacts and stakeholders socioeconomic requirements as key elements for sustainability.
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