Prey switching of Dall's porpoise Phocoenoides dalli with population decline of Japanese pilchard Sardinops melanostictus around Hokkaido, Japan
Prey switching of Dall's porpoise Phocoenoides dalli with population decline of Japanese pilchard Sardinops melanostictus around Hokkaido, Japan
复制标题
DOI：
10.3354/meps200265
复制
发表时间：
2000-01-01
影响因子：
2.5
通讯作者：
Miyazaki, N
中科院分区：
文献类型：
--
作者：
Ohizumi, H;Kuramochi, T;Miyazaki, N
对1988~1996年在日本海和北海道周边鄂霍次克海6次调查中采集的150头达尔氏江豚的胃内容物进行了研究。共鉴定出49种猎物类型，包括29种。中午采集的样品中发现了上层捕食物，上午采集的样品中发现了中上层和一些底层捕食物种。虽然猎物的体型范围很大，但大多数猎物都很小。从20世纪80年代末到90年代初，两个海域的主要猎物物种都发生了变化，因为两个海域的黑腹沙丁鱼(日本沙丁鱼)数量都在下降。在日本海，Dall的江豚的饮食转向了Theragra cocogram ma(大眼鳕鱼)，而在鄂霍次克海，它们的饮食转向了Engraulis Japan onicus(日本凤尾鱼)和Berryteuthis Magister(地方长官臂钩鱿鱼)。新猎物物种的利用并不总是与当地渔业中猎物渔获量统计的波动相一致。当没有上层捕食物种时，达尔氏江豚以许多底层捕食物种为食，这表明上层捕食物种是首选猎物。猎物的垂直分布可能会影响猎物的选择。
The stomach contents of 150 Dall's porpoises collected during 6 surveys in the Sea of Japan and Sea of Okhotsk around Hokkaido in 1988 to 1996 were examined. A total of 49 prey types, including 29 species, were identified. Epipelagic prey items were found in samples collected during midday, and mesopelagic and some benthopelagic prey species were found in samples collected in the morning. Although the size range of prey was great, most prey were small. The dominant prey species switched in both seas from the late 1980s to the early 1990s as the Sardinops melanostictus (Japanese pilchard) populations in the both seas declined. In the Sea of Japan, the diet of Dall's porpoises switched to Theragra chalcogramma (walleye pollock), and in the Sea of Okhotsk, their diet switched to Engraulis japonicus (Japanese anchovy) and Berryteuthis magister (magistrate armhook squid). The utilization of new prey species did not always coincide with the fluctuation in catch statistics for the prey in local fisheries. Dall's porpoises fed on many benthopelagic prey species when epipelagic prey species were not available, suggesting that epipelagic prey species are the preferred prey. The vertical distribution of prey presumably affects prey selection.