title: [Environmental characteristic of walleye pollock fishing ground in high seas of the Okhotsk Sea in summer].
abstract: Based on the acoustic survey on the resource of walleye pollock (Theragra chalcogramma) in the high seas of the Okhotsk Sea, the distribution of walleye pollock and the environmental characteristics of its fishing ground were studied, and the relationship between them were analyzed. In August, the high schooling area of walleye pollock was situated in the waters with a depth of less than 500 meters and to the north of 55 degrees N. Walleye pollock mainly distributed in 150-300 m depth, and lived in groups. The main food was Euphausia pacifica, and the densely populated area of wall-eye pollock was roughly consistent with that of Euphausia pacifica. The thermocline was observed at 0-50 m depth, the temperature changed at a rate of 0.25 degree C per meter, and the cold water mass was roughly located in 50-150 m layer. The fish was mainly distributed in the layer below the cold water mass, because of the impeding effect of thermocline and the limiting action of fish food. It seldom inhabited the water below 400 m depth, partly because the dissolved oxygen there was rather low.
authors.affiliation: Yellow Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Qingdao 266071.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: Q
authors.initials: Q
authors.lastname: Tang
mesh_terms: D000818:Animals; D004777:Environment; D005398:Fisheries; D005399:Fishes / Q000502:physiology*; D008386:Marine Biology; D010140:Pacific Ocean; D012621:Seasons