Genetic connectivity of Fenneropenaeus indicus (H. Milne Edwards 1837) among three prawn fishing grounds of Tanzanian coastal waters

The penaeid prawn fishery of Tanzanian coastal waters occurs within three main fishing grounds referred to as zone 1, 2 and 3. The three zones are connected to major estuaries of Ruvu, Rufiji and Matandu rivers, respectively. The genetic connectivity of Fenneropenaeus indicus population in those areas had not been previously studied. The population study was performed to test the hypothesis that only a single population exists in the area, utilizing the mitochondrial DNA (mtDNA) sequence data. There were 89 sequences of F. indicus used in the analysis. Results indicated that there were 36 haplotypes and the mean haplotype diversity (h) was relatively moderate when there was a low level of nucleotide diversity (π). The FST values ranged from −0.00798 to 0.00918 indicating the absence of differentiations between localities. The Tajima's D and Fu's Fs statistic showed the presence of recent expansion of the population. An analysis of molecular variation (AMOVA) indicated a higher variation within a population than among populations. The study established that the populations existing in the three prawn fishing grounds were a panmictic population. Thus, the reconsideration of the geographical distribution of the fishing grounds (Zones 1-3) and extension of closed season management strategy to the artisanal fishers are recommended. Further study is recommended using nuclear markers to infer population structure in the coastal waters of Tanzania.