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Shirati Bay is among the important breeding and nursery sites for major fish species in Lake Victoria. Weekly samplings were conducted to assess the temporal patterns in phytoplankton, zooplankton and fish composition, abundance and biomass in relation to prevailing water quality parameters. The study also determined the influences of plankton dynamics and water quality on the fish catch composition and biomass. It was hypothesized that temporal patterns in the composition, abundance and biomass in the plankton in the bay are controlled by water quality parameters that, in turn, affect the composition and biomass of fish catches. The phytoplankton comprised mainly cyanophytes and bacillariophytes, while the zooplankton were dominated by copepods. The heavy rain season exhibited a significantly higher plankton abundance and biomass than the dry season. The plankton abundances in both seasons exhibited significant positive correlations with water temperature and transparency. The phytoplankton community was controlled by calanoid and cyclopoid species. At higher trophic levels, Lates niloticus juveniles, Oreochromis niloticus juveniles and haplochromines controlled Cladocera and Cyclopoid copepods, while Tilapia rendalli juveniles controlled the Rotifera. This study revealed that Cyanophyta and Bacillariophyta are the dominant phytoplankton, whereas cyclopoids dominate the zooplankton species in the bay. These dominant plankton groups are partly controlled by rainfall, water temperature and transparency. Fish biomass, zooplankton and phytoplankton exhibit a typical predator-prey inverse relationship. Thus, evaluation of the plankton composition, abundance and biomass should be mandatory during fisheries stock assessments to effectively manage the fishery resources in the bay.

The catchment and water chemistry of Lake Victoria are greatly influenced by the inflow of rivers and the alternation of the dry and wet seasons. The ecological integrity of the lake has been altered as a result of changes in its physical, chemical, and biological properties resulting from natural and anthropogenic forces. With human population growth, there has been an increase in the multiplicity of activities in the lake basin rendering the lake environmentally unstable.The diversity of the fauna, especially of fish and of the flora declined and the health of the ecosystem deteriorated due to excessive fishing pressure, predation, and competition among introduced species, wetland degradation, poor watershed management and pollution. The nutrient content in Lake Victoria has increased and the consequent eutrophication had a big impact on the biodiversity of the cichlids.Factors that had been affecting Lake Victoria had not impacted the small water bodies in the basin on the same scale. There are several pockets of rare and even extinct species in Lake Victoria that still survive in several ox-bow lakes associated with the extensive wetlands around Lake Victoria. The phytoplankton, zooplankton and fish communities known to be missing in the main lake continued to survive in these minor water bodies. Species still occurring in both habitats exhibit different levels of tolerance to exploitation levels. However, there is no clear policy to conserve the minor water habitats. The paper compares the common taxa in Lake Victoria and the satellite lakes identifying the rare ones in an attempt to mobilize forces to conserve them.