High genetic diversity and panmictic population of Malabar trevally (Platycaranx malabaricus)

Overfishing is one of the main factors explaining the collapse of fish stocks, including the commercially important marine species, such as the Malabar trevally (Platycaranx malabaricus). Assessing the population genetics and later integrating genetic information into the management and conservation strategy is thus a crucial effort to address the harvest pressure. In this study, we examined 117 individuals of P. malabaricus from seven populations covering the four marine regions of Malaysian waters (Malacca Strait, South China Sea, Sulu Sea, and Celebes Sea) using the mitochondrial DNA control region (CR) and the nuclear recombination activating gene 1 (RAG1). An overall high genetic diversity was observed (CR: haplotype diversity (h) = 0.9909 $$\:\pm\:$$ 0.0032, nucleotide diversity (π) = 1.93 $$\:\pm\:$$ 1.00%; RAG1: h = 0.7764 $$\:\pm\:$$ 0.0382, π = 0.30 $$\:\pm\:$$ 0.19%). Populations of P. malabaricus were panmictic, presumably facilitated by adult migration, and planktonic larvae drift through ocean currents. A historical population expansion was evident during the Pleistocene epoch, suggesting secondary contact between several glacial refugial populations. This study provides valuable information on population genetics of P. malabaricus to recommend proper management and conservation plans.