It has been reported that Wild L. Victoria Oreochromis niloticus have disappeared from about 40% of their historical breeding ranges. This study was conducted to determine the effect of different microhabitat types on the species distribution and yield performance around Port Bunyala Bay. Physical parameters (Temperature, Total depth and Conductivity) which contributes to the dispersal and yield performance of the species in freshwater systems were measured Insitu by multi-parameter probe YSI - 16820, Instrument readable up to 0.01°C while, multi-mesh gillnet of 14 – 90 mm was used to capture fish specimen. Chemical water parameters were sampled and analyzed in laboratory according to procedures outlined in [30], [18] and [2]. Fish yield and distribution data collected were analyzed by One Way ANOVA, p < 0.05 to determine if there existed any significant difference in Oreochromis niloticus distribution and yield among microhabitat types and Post hoc Tukey’s HSD, p < 0.05, to determine if there was significant difference between a pair of microhabitat types. Finally, Karl- Pearson product moment correlation coefficient, r, was used to determine the relationship between measured values of water quality, variables, yield and the fish distribution. Results of One Way ANOVA, p < 0.05, gave significant differences among microhabitats: for distribution, (F0.05, 3, 16 = 1201.09) and yield (F0.05, 3, 16 = 49.45) with MH 3 having highest number of fish caught (31%) and total yield (41.50%). Turkey’s HSD comparison of results revealed significant differences for distribution and the total fish yields. Estimated potential yield were far below gill-net catches and showed that the species potential yield has declined by between 65-99 % in yields. The study concluded Port Bunyala Bay is under abiotic stress and therefore, a cross-sectoral approach to ecosystem based management of the important to rehabilitate and protect the fish breeding sites.

Keywords: Port Bunyala Bay, microhabitat type, Oreochromis niloticus, distribution, yield