DNA evidence for a population bottleneck in Lake Victoria Nile perch

Abstract

A recent decline in Nile perch abundance in Lake Victoria is of concern to the fishing industry. To determine if this decline threatens the persistence of Nile perch, we quantified the level of genetic variation and the structure of its populations. Samples of Nile perch from lakes Victoria and Turkana were characterized by a single haplotype, while those from Lake Albert exhibited two haplotypes varying in a single T-C transition. Variation across the seven microsatellites was low with allelic richness ranging from 2.6 to 3.3. Bayesian analysis of genetic structure showed all samples belong to one population, consistent with a low genetic differentiation (FST = 0.054; p ≥ 0.05). Patterns of allelic distribution and heterozygote excess suggested a recent population bottleneck. Such species are either threatened or endangered based on their low genetic diversity, lack of genetic differentiation among populations, molecular signatures of recent bottleneck, and reduced census