Abstract:

This study explores water quality parameters and their effect on fish abundance and diversity in Lake Victoria. Fish are considered as water quality indicators, especially due to their sensitivity to pollution. The municipal and industrial discharges is visible through the channels draining into the lake, which potentially increases pollution levels. This is a real threat to aquatic life and the health of humans who consume fishery resources of the lake. Three sites were selected (site1, site2 and site 3) where water and fish were sampled weekly for a month. The results of water quality showed temperature range of 26.40 C- 28.80 C; pH 9.34-7.23; turbidity 10.6NTU- 5.3NTU; E.C 134.17µs/cm- 216µs/cm and D.O 6.1mg/l- 6.9mg/l. All the physiochemical parameters of water were within the standard levels suitable for freshwater fish survival and growth. However, there were mean differences in water quality among the sites. For example, site 1 which was located direct to Nakivubo channel had turbidity and D.O levels of 10.6NTU and 6.4mg/l, respectively compared to site 2 and 3 which had turbidity less than 10NTU. Nile tilapia was the most abundant fish species in all the sites, followed by juvenile Nile perch while haplochromine was only caught in site 3 far away from the sewage discharge point. In addition, the numbers of tilapia decreased with turbidity indicating their habitat preference while Nile perch showed a uniform distribution across the sites. In conclusion, different water quality parameters potentially influenced fish distribution and abundance, but future comprehensive study could yield more reliable results. Therefore, there should be monitoring of water quality for better management of fishery resources of Lake Victoria.