Genetic diversity among tilapia species farmed at Chita in Kilombero, Morogoro region, Tanzania

Molecular techniques such as the Deoxyribonucleic acid (DNA) markers are commonly used to examine intra and inter-population variation among fish strains. This study was conducted to identify species of tilapia cultured in small scale earthen ponds at Chita, Kilombero in Morogoro region Tanzania. The study also determined the genetic diversity of these fish species through the microsatellite DNA marker also called simple sequence repeat (SSR). A total of 89 sequences were produced, based on maximum likelihood (ML) a phylogenetic tree was constructed. Blasting through the National Center for Biotechnology Information (NCBI) database enabled the identification of the sequences as Oreochromis niloticus. Nucleotide and molecular diversity were 0.588518 ± 0.282253 and 1.0000 ± 0.0017 respectively, due to inbreed effect low genetic diversity was observed. There was a significant correlation between length and weight. The value of the regression co-efficient (r2) obtained from the length weight relationship (WLR) was 0.745. The fish showed negative allometric growth of b=-2.7. Condition factor computed for O. niloticus was 2.24, which indicated good health of the fish during the study period. Findings from the present study suggest that increased aquaculture activities if not properly controlled can led to continued species introduction and introgression, thus endangering genetic diversity which forms an important role in both small scale and commercial fisheries.