DNA barcode-based identification of commercially caught cutlassfishes (Family: Trichiuridae) with a phylogenetic assessment

摘要

One cutlassfish species, the common hairtail (Trichiurusjaponicus), forms large populations on the western North Pacific continental shelf, where fisheries exploitation is extensive, and the stocks have suffered overfishing. For the purpose of stock identification and fisheries management, an accurate and efficient method of identifying species and separating compound catch samples with desirable accuracy is needed. Up to twelve cutlassfish species may be mixed in catches: they have similar external morphologies and the existing taxonomic keys are somewhat vague, making accurate field identification difficult. Herein, we prepared 12 DNA consensus sequences of 651 base pairs of the mitochondria] cytochrome c oxidase subunit I (COI) gene for each species, as a species-specific barcode to facilitate the correct identification of commercial catch compositions and processed products. These standard barcode sequences showed high interspecific differences, together with high within-species similarities (>95% similarity). The degree of interspecific differences basically conformed to the age of phylogenetic origin, and thus barcode differences were genetically comprehensive. To validate their effectiveness, we tested cutlassfish samples taken from markets (both fresh and frozen), and the results revealed high reliability. The developed protocols are of value for both conservative fisheries management and governmental scrutiny of labeling of cutlassfish products