To better understand the gastropod community dynamics of fresh water snails in the Upper Victoria Nile (UVN), the spatial and temporal abundance changes in gastropod assemblage were assessed biannually from April 2006 to April 2021 at three transects. Biannual abundances of gastropoda were obtained by a ponar grab to examine changes in their community structure in relation to Bujagali Hydropower Project (BHP). The gastropod community consisted of nine speciesbelonging to five families (Thiaridae, Viviparidae, Ampullariidae, Bithyniidae and Planorbidae). Pulmonate species registered five species <i>(Anisus natalensis, Gyraulus sp., Segmentorbis sp., Bulinus sp. and Biomphalaria chaonomphola)</i>. Two of the pulmonates <i>(Bulinus sp. and B. chaonomphala)</i> are schistomiasis vectors. The pulmonates <i>(A. natalensis, Gyraulus sp., Segmentorbis sp.)</i> were rare and intermittently occurred with abundances up to 47 ind.m-2. Four prosobranch species <i>(Gabbia humerosa, Pila ovata, Melanoides tuberculata and Bellamya unicolor)</i> were encountered. Of these prosobranchs, <i>P. ovata</i> was the rarest while <i>M. tuberculata</i> and <i>B. unicolor</i> were the commonest. The gastropod community in the UVN was characterised by prosobranchs-dominated abundance which over the 16-year monitoring period often registered peak densities of > 1000 ind.m2. The inter-site Percent Similarity Index (PSI) (94-100%) indicated a high degree of similarity of gastropod community across the sites.

This study investigated the catch estimates, mortality, growth, food and feeding habits, and water parameters of Oreochromis variabilis in Upper Victoria Nile (UVN) from 2008 to 2019. Catch rates ranged 0.32±0.08 to 3.42±1.13 kg, boat-1, day-1 with the length-weight relationship indicating Isometric growth. Growth parameters obtained were L∞=36.75, K=0.44 yr-1, t0=-0.4540, tmax=6.4years, ØL=2.774, ØW=-0.301. Total mortality (Z) was 1.74yr-1, natural mortality (M) =0.95yr-1 using riverine surface temperature (RST) of 26oC giving a fishing mortality F of 0.79 yr-1 and exploitation ratio (E) of 0.4504 showing that growth parameters concurs with annual estimates and yield (F=6.589; P±=0.05). Catch estimates correlated with water parameters that indicated a significant difference. Mortality parameters showed that the fishery could be experiencing exploitation pressure. Although growth rates revealed that the fish is a long-lived species, if managed properly, its population could recover. Therefore, culturing the species and restocking in rivers and lakes in which this specie was not observed in the East African region are recommended.