Genetic diversity, population structure and morphological characterization of the silver cyprinid Rastrineobola argentea (Pellegrin) in Port Victoria, Mbita and Nyanza Gulf of Lake Victoria (Kenya)

Abstract

Rastrineobola argentea, ‘omena’ is one of the smallest cyprinid fishes found in the Lake Victoria basin. Currently, R. argentea is the most commercially exploited species of Lake Victoria (62.2%) compared to those of Lates niloticus L (29.9%) and Oreochromis niloticus L (6.9%). The objective of this study was to morphologically characterize R. argentea, determine its genetic diversity and population structure of and test for phylogenetic relationships between three populations in Lake Victoria (Kenya) using SSR, CO1 gene and mtDNA genome. A random stratified sampling was done in a cross-sectional experimental design. A one-way analysis of variance was used to determine whether there was a significant difference between the means of the three populations of fish namely Nyanza Gulf, Port Victoria and Mbita. The results of the one-way ANOVA indicate that the critical Fstatistic, 24.05, was greater than the F critical value thereby rejecting the null hypothesis. Comparing values generated using Fisher’s exact test confirms that population from Mbita and that of Nyanza Gulf are closely related compared to those of Port Victoria. The Phylogenetic analysis indicated that Mbita population and Nyanza Gulf population were found in the same sub cluster signifying that they are more closely related to each other than to Port Victoria. This signifies that the morphological analysis concurs with the molecular data. Conservation of genetic diversity in species of commercial interest like R. argentea fisheries in Lake Victoria is essential to the long-term survival of any species, particularly in light of changing environmental conditions and human pressure.