Food Habits of Walleye Pollock Inhabiting the Mesopelagic Zone in the Northern Japan Sea in Spring and Autumn
Food Habits of Walleye Pollock Inhabiting the Mesopelagic Zone in the Northern Japan Sea in Spring and Autumn
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春秋季栖息于日本海北部中深层的狭鳕的食性
DOI：
10.2331/suisan.63.537
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发表时间：
1997
影响因子：
0.4
通讯作者：
Toyomi Takahashi
中科院分区：
文献类型：
--
作者：
K. Kooka;T. Takatsu;Yoshihiko Kamei;T. Nakatani;Toyomi Takahashi
于1993年4月、10月和1994年4月对狭鳕的食性和摄食强度进行了调查。在日本海北方的桧山县和青森县近海，用中层拖网采集了标准长度为262 ~ 456 mm的样品。主要食物为大型浮游动物。在四月，狭鳕主要以磷虾类（Thysanoessa longipes）、毛颚类（Chaetognaths）和片脚类（Themisto japonica）为食。10月份的主要食物生物为超形端足类（T. japonica）。胃内容物重量指数表明，4月（产卵后）的鳕鱼的摄食强度比10月（产卵前）。4月份食物种类的数量组成在采样站之间存在差异。10月份没有观察到这种差异。四月份食物的明显变化可能归因于中层浮游动物组成的地理差异。
The diet and feeding intensity of walleye pollock Theragra chalcogramma were investigated in April and October 1993, and in April 1994. Specimens ranging from 262 to 456mm in standard l ength were sampled with a mid-water trawl off Hiyama Subprefecture and Aomori Prefecture in the northern Japan Sea. The main food items were large-sized zooplankton. In April, pollock fed chiefly on euphausiids (Thysanoessa longipes), chaetognaths, and hyperiid amphipods (Themisto japonica). In October, the main food organisms were hyperiid amphipods (T. japonica). Stomach-content weight indices indicated that the feeding intensity of pollock was stronger in April (after spawning) than in October (before spawning). The numerical compositions of food categories in April differed among sampling stations. Such differences were not observed in October. It seems likely that the dis tinct variation of diets in April is ascribed to geographic differences in zooplankton composition in the mesopelagic zone.