Abstract:

Adjustments in fish species diversity, prey selection and life history characteristics
niloticus L. of Nile perch, Lates in lakes Victoria, Kyoga and Nabugabo before and after its establishment were examined and compared with the situation in Lake Albert and other habitats where the predator is native. Fish species diversity in the new habitats initially decreased from a level that was similar to that in Lake Albert to one that was significantly lower and then persisted when species that are apparently resilient to Nile perch predation remained. Afterwards, stocks of some species began to recover. The types of prey eaten in the new habitats changed from predominance of
haplochromines to types, sizes and numbers similar to those eaten in Lake Albert and other condition factor of the native habitats. Nile perch which was the initially higher in the new habitats decreased and remained at values which although lower than in Lake Albert, are not below the lowest values recorded in a native habitat. Growth rates of juvenile Nile perch native habitats. Were within the ranges reported in The size at first maturity shifted from smaller to larger sizes, which are similar to those in lake Albert. this increases overall reproductive potential because fecundity is proportional to the cube of the length. Only the proportion of females in invaded lakes decreased to significantly lower reason for this is values than obscure. in Lake Albert Since all but one but the of the variables examined have converged on values indicative of the situation where Nile perch has remained in balance with its prey community for lakes a long time, the fisheries of the recently invaded by Nile perch can stabilize and sustain product.