Summer distribution of fishes and squids caught by surface gillnets in the western north Pacific Ocean

We surveyed the summer distribution of epipelagic nekton in the western North Pacific Ocean, and examined species distribution with respect to oceanographic structure. Fishes and squids were collected using surface gillnets along a north-south transect at 165 degrees E longitude, between 41-51 degrees N latitude in summer 1992-1998. The transect crosses the Subtropical North Pacific (STNP). the Transition Domain (TD) , and the Western Subarctic Gyre (WSG). Twenty-six fish species, four squid species, one marine mammal species and some other unidentified fish and sea bird species were collected. The most abundant species were Pacific salmon (six species of the genus Onchorhynchus, 68% in number), followed by Pacific saury (Cololabis saira, 16%) , Atka mackerel (Pleurogrammus monopterygius, 5%), Pacific pomfret (Brama japonica, 3%) , and blue shark (Prionace glauca, 1%). Abundant squid species included neon flying squid (Ommastrephes bartramii, 2%) , boreal clubhook squid (Onychoteuthis borealijaponica, 2%), and boreopacific gonate squid (Gonatopsis borealis, 1%). Pacific salmon were distributed in the TD and WSG, and sockeye (O. nerka, 6%). chum (O. keta, 7%), pink (O. gorbuscha, 50%), and coho salmon (O. kisutch, 5%) were distributed in this order from north to south. Pink salmon showed a clear year-to-year variation in abundance, which was higher in even years than in odd years. Boreopacific gonate squid were distributed mainly in the WSG at sea surface temperatures (SST) below 10 degrees C, but also occurred in the TD in 1997. Neon flying squid were distributed in the TD at 10-15 degrees C SST, and were abundant in 1994 and 1996. Boreal clubhook squid and Pacific pomfrel occurred in the TD, and Pacific saury were distributed south of the 10 degrees C SST isotherm. In 1994 Atka mackerel were abundant at 51 degrees N, where the northern part of WSG flowed westward