Examination of saffron cod (Eleginus gracilis) population genetic structure

Abstract

The Saffron Cod (Eleginus gracilis) is an abundant forage fish that inhabits the coastlines of the north Pacific and Arctic oceans. We examined Saffron Cod population genetic structure to provide a reference baseline in anticipation of human and climate-change alterations of the Arctic environment. Nine microsatellites were designed to describe the genetic compositions of and variation among 40 collections of Saffron Cod from four regions (northwestern Alaska, Gulf of Alaska, Sea of Okhotsk, and Gulf of Anadyr). The northwestern Alaska collections (Bering Sea, Norton Sound, and Chukchi Sea) exhibited little genetic divergence. The Gulf of Anadyr collection differed from other regions but was most similar to those of the northwestern Alaska region. The two collections within the Sea of Okhotsk (Sakhalin Island and Hokkaido Island) differed genetically, but not to the extent they did from other regions. The collections from the Gulf of Alaska (Kodiak Island and Prince William Sound) comprised a lineage that was distinct from all of the other collections, including the geographically adjacent northwestern Alaska collections. The absence of genetic structure among northwestern Alaska collections probably reflects their recent expansion into previously unavailable habitat that became available after the Last Glacial Maximum (~16,000 years ago). The divergence of the Gulf of Alaska lineage may have resulted from recurrent episodes of isolation from previous glaciations.