Tilapia guineensis is an important economically and nutritionally important fish commonly found in Nigerian coastal waters. Genetic diversity of the fish was assessed to obtain information that may help in developing appropriate conservation and breeding programmes for improving the economic and nutritional quality of the fish. Twelve (12) Nigerian coastal populations and nine microsatellite loci were considered. All the loci were multi-allelic giving an average of 3.1 alleles per locus. The number of alleles (Na) ranged from two to four alleles per locus while the effective number of expected alleles (Ne) ranged from 1.087 to 2.612. Buguma, Badagry and Brass populations had the highest genetic diversity as was revealed by heterozygosity (observed and expected) and shannon index of the populations. The longest pairwise genetic distance of 0.30 was between Brass in Bayelsa State and River Ethiope in Delta State. Clustering using simple sequence repeat (SSR) data gave four major clusters which did not concur with geographical location clustering. We conclude that although genetic diversity is low in some populations of T. guineensis in Nigerian coastal waters, some populations (Buguma, Badagry and Brass) still retain some genetic variability which may be explored for fish improvement through appropriate breeding and conservation programmes.  

 

Key words: Molecular characterization, genetic diversity, microsatellite analysis, Tilapia guineensis, coastal rivers.