Genetic polymorphism and phylogenetic relationships of the brushtooth lizardfish ( Saurida undosquamis ) (Aulopiformes: Synodontidae) based on mitochondrial DNA markers

The brushtooth lizardfish ( Saurida undosquamis ) is an economically important demersal fishery resource, yet several aspects critical for its conservation are poorly studied. This study examined the genetic variability and structure of S. undosquamis from the east coast of Peninsular Malaysia (ECPM), Malaysia, and its broad-scale phylogenetic relationships inferred from the mitochondrial 16S rRNA and COI gene markers, respectively. Results showed that S. undosquamis from the ECPM was characterized by a moderate haplotype diversity and a low nucleotide diversity. These characteristics coupled with historical demography analyses suggest a recent population expansion during the Late Pleistocene epoch. A significantly higher nucleotide polymorphism of S. undosquamis inhabiting near shore and shallower waters was observed, suggesting a better habitat quality for survival and/or less fishing pressure at these areas. Protecting these areas is critical to maintain these genetically healthy populations. Genetic homogeneity within the ECPM (panmixia) was observed, attributed to its dispersal ability, water currents, absence of physical barrier to gene flow, and/or range expansion. This recommends for a single-stock management regime for S. undosquamis in this region. Saurida undosquamis from the ECPM, South China Sea, and Japan (East China Sea) were genetically closer with individuals from the Mediterranean coast of Turkey, as evident from all relevant analyses despite being more distant than the Indian Ocean populations.