Consumption of juvenile chum salmon by a seabird species during early sea life
Consumption of juvenile chum salmon by a seabird species during early sea life
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早期海洋生活期间海鸟对幼年大马哈鱼的消耗
DOI：
10.1016/j.fishres.2019.105415
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发表时间：
2020
影响因子：
2.4
通讯作者：
Watanuki Yutaka
中科院分区：
文献类型：
--
作者：
Okado Jumpei;Koshino Yosuke;Kudo Hideaki;Watanuki Yutaka
幼鱼的死亡率，一个关键因素，确定的股票规模的鲑鱼，可能会增加捕食在河流和沿着海岸。然而，有关海上捕食的信息却很少。我们分析了饮食的远洋海鸟，犀牛aukletCerorhinca monocerata，繁殖在日本北海道东部的一个孤岛上，估计他们的消费少年chum鲑鱼Oncorhynchus凯塔。小海雀为它们的幼鸟带来了幼鲑鱼和日本鳀鱼，此外，它们自己也以鱿鱼为食。大部分幼鲑的叉长超过80 mm，表明它们正在迁移到鄂霍次克海的近海育苗区。使用一个简单的生物能量学模型，在小鸡饲养期的前半段（6月下旬至7月中旬），小海雀对幼鲑的消费量在2014年为316.6吨（成人296.4吨，小鸡20.2吨），2015年为11.7吨（成人0吨，小鸡11.7吨）。在66个幼鲑的饮食中发现的小鸡的耳石有热标记，并表明这些鱼被释放的河流沿着太平洋沿岸的北海道。我们的研究首先证明了小海雀的消费有助于减少在开放的沿海地区的幼鲑与已知的股票来源的生存程度。
Juvenile mortality, a key factor determining the stock sizes of salmonids, may be increased by predation both in rivers and along shores. Information on predation at sea, however, is scarce. We analysed the diet of a pelagic seabird, the rhinoceros aukletCerorhinca monocerata,breeding on an isolated island off eastern Hokkaido, Japan, and estimated their consumption of juvenile chum salmonOncorhynchus keta. The auklets brought juvenile chum salmon and Japanese anchovyEngraulis japonicusfor their chicks and, in addition, fed on squid themselves. The fork length of most of the juvenile chum salmon was over 80 mm, indicating that they were migrating to offshore nursery area, the Sea of Okhotsk. Using a simple bioenergetics model, the consumption of juvenile chum salmon by auklets during the first half of chick-rearing period (late June to middle July) was 316.6 t in 2014 (296.4 t by adults, 20.2 t by chicks) and 11.7 t in 2015 (0 t by adults, 11.7 t by chicks). The otoliths of six out of 66 juvenile salmon found in the diet for chicks had thermal markings and indicated that these fish were released from the rivers along Pacific coast of Hokkaido. Our study first demonstrates the extent of the auklets' consumption contributing to the reduction of the survival in the open coastal area of juvenile chum salmon with the known stock origins.