Rex Ferdinand M. Traifalgar

Cryptic genetic divergence in Scolopsis taenioptera (Perciformes: Nemipteridae) in the western Pacific Ocean

We studied the phylogeny, population structure, and demographic history of Scolopsis taenioptera in the western Pacific Ocean. Using the 80 samples collected from four locations, we obtained the nucleotide sequences of mitochondrial cytochrome c oxidase subunit I and cytochrome b genes. We identified two distinct lineages showing a clear phylogeographic break that was possibly due to the Pleistocene sea-level change. One lineage was distributed in Iloilo (Philippines) and the other in Terengganu (Malaysia), Rayong (Thailand), and Ha Long Bay (Vietnam). The Terengganu and Rayong populations showed clear signs of demographic expansion; the Iloilo and Ha Long Bay populations were relatively stable or spatially expanded as geographically subdivided populations.

Rapid and cost-effective molecular identification of the three mackerel species of the genus Rastrelliger (Perciformes: Scombridae) using PCR-RFLP analysis

The three mackerel species, Rastrelliger kanagurta, Rastrelliger brachysoma, and Rastrelliger faughni, co-occur in the central part of the Indo-West Pacific Ocean, and together represent important fisheries resources. However, they have sometimes been collectively referred to as “Rastrelliger spp.” in the fisheries statistics, owing to their morphological similarity. Therefore, species-specific data on landings, effort, and population status are lacking, undermining the appropriate resource management. The present study provides a rapid and cost-effective method based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis to distinguish the three species. Digestion of the PCR products of 1247 base pairs of mitochondrial DNA encompassing the complete sequence of cytochrome b gene using two restriction enzymes yielded diagnostic restriction patterns for the three species, thereby enabling accurate identification.