Genetic Stock Structure of Terapon jarbua in Taiwanese Waters

Abstract

Over the past century, stock identification, which is crucial for fisheries stock assessments, has relied heavily on intraspecies variations to differentiate management units. In recent years, however, DNA approaches have shed additional light on some aspects of the natural history and ecology of species and stocks. The Crescent Grunter Terapon jarbua is widely distributed across the Indo‐Pacific region. It inhabits coastal waters with sandy substrates and tends to aggregate in estuaries. In the present study, we collected 96 individuals of T. jarbua from 10 locations around the shoreline of Taiwan as well as near Guangdong, China. A concatenated sequence (1,753 bp) of mtDNA (cytochrome c oxidase I and cytochrome b) was obtained from all individuals. We discovered two genetically distinct clades (lineages A and B) with different historical demographies occurring sympatrically except at the Yilan collection site, which was dominated by lineage A haplotypes. Connectivity within this region is high according to F_ST and AMOVA tests. The genetic variation between the two clades is far below the interspecies threshold for the genus Terapon (0.007 versus 0.3156). Therefore, we suggest that they be considered different genetic stocks from a fisheries management point of view and that future stock reassessment should be conducted based on the genetic information provided in this study. Further large‐scale sampling is needed to understand the mechanisms that drive genetic partitioning on regional (Northwest Pacific) and global (Indo‐Pacific) scales.

Received February 9, 2015; accepted July 9, 2015