夏季鄂霍茨克海公海区狭鳕渔场环境特征

Environmental characteristic of walleye pollock fishing ground in high seas of the Okhotsk Sea in summer.

根据鄂霍茨克公海区狭鳕资源声学评估调查资料 ,研究了狭鳕分布状况及渔场环境特征 ,并分析了狭鳕行动分布与环境的关系 .结果表明 ,8月公海区狭鳕密集群位于 5 5°N以北、水深小于 5 0 0m的海域 ,其主要分布水层在 15 0～ 30 0m之间 ;调查期间狭鳕只为索饵群体 ,主要摄食太平洋磷虾 ,狭鳕密集区一般也为太平洋磷虾高密度分布区 ;8月公海区水温跃层大致在 0～ 5 0m之间 ,强度为 0 .2 5℃·m-1左右 ;冷水团位于 5 0～ 15 0m之间 ;由于温跃层的屏障作用和饵料因素的影响 ,狭鳕主要分布于冷水团以下的水层 .40 0m以下的水层狭鳕分布稀少 ,部分原因是溶解氧含量过低 .

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°N.Walleye pollock mainly distributed in 150～300m depth,and lived in groups.The main food was Euphausia pacifica ,and the densely populated area of walleye pollock was roughly consistent with that of Euphausia pacifica .The thermocline was observed at 0～50m depth,the temperature changed at a rate of 0.25℃ per meter,and the cold water mass was roughly located in 50～150m 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 400m depth,partly because the dissolved oxygen there was rather low.