Demersal fish diversity and molecular taxonomy in the Bering Sea and Chukchi Sea

DNA barcoding by sequencing a standard region of cytochrome c oxidase subunit I (COI) provides an accurate, rapid method for identifying different species. In this study, we provide a molecular taxonomic assessment of demersal fishes in the Bering Sea and Chukchi Sea based on DNA barcoding, and a total of 123 mitochondrial COI partial fragments with a length of 652 bp were obtained. The consensus among all sequences was determined by alignment via a BLAST search in GenBank. Phylogenetic relationships were reconstructed based on neighbor-joining trees and barcoding gaps. The 39 species investigated in this analysis were distributed among 10 families. Five families within Scorpaeniformes including 19 species accounted for almost half of the species. The next largest group was Perciformes, with 9 species, followed by Pleuronectiformes and Gadiformes, with 5 species each, and the smallest number of species belonged to Rajiformes. At the family level, Cottidae was the largest family, followed by Zoarcidae, accounting for 8 species. The other eight families-Gadidae, Pleuronectidae, Psychrolutidae, Agonidae, Liparidae, Ammodytidae, Hexagrammidae, and Rajidae-accounted for a smaller proportion of species. In brief, our study shows that DNA barcodes are an effective tool for studying fish diversity and taxonomy in the Bering Sea and Chukchi Sea. The contribution of DNA barcoding to identifying Arctic fish species may benefit further Arctic fish studies on biodiversity, biogeography and conservation in the future.