Foraging tactics of Baikal seals differ between day and night
Foraging tactics of Baikal seals differ between day and night
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DOI：
10.3354/meps279283
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Miyazaki, N
中科院分区：
文献类型：
--
作者：
Watanabe, Y;Baranov, EA;Miyazaki, N
一些鳍足类物种似乎在白天和夜间都觅食。为了确定白天和夜间觅食策略的差异，我们将带有新开发的定时释放系统的数据记录器连接到两只自由放养的雌性贝加尔海豹西伯利亚海豹身上。该系统在部署 24 小时后将记录仪从密封中释放出来，并允许我们通过 VHF 无线电信号取回记录仪。我们首次获得了贝加尔海豹的时间序列潜水数据。海豹几乎连续下潜，平均下潜深度为 68.9 m，比此更深的下潜深度（>150 m）集中在黄昏和黎明时分。他们在白天和晚上的游泳速度曲线和最大潜水深度的顺序模式方面表现出明显不同的潜水模式。白天，潜水的特点是较高的游泳速度（平均 1.2 m s(-1)）和向上的加速事件。夜间，午夜前后潜水较浅，特点是速度较低（平均 0.9 m s(-1)）和无方向性减速事件。我们认为这些差异反映了海豹在白天利用视觉线索捕食远洋鱼类，以及海豹在夜间利用触觉线索捕食成群的甲壳类动物。
Some pinniped species appear to forage during both daylight and darkness. To determine any differences in the foraging tactics between day and night, we attached data loggers with a newly developed time-scheduled release system to 2 free-ranging female Baikal seals Phoca sibirica. The system released the loggers from the seals 24 h after deployment, and allowed us to retrieve the loggers via VHF radio signals. We obtained the first time-series diving data on Baikal seals. The seals dived almost continuously, to an average of 68.9 m, with dives deeper than this (>150 m) being concentrated around dusk and dawn. They showed distinctly different diving patterns between day and night in terms of swimming speed profile and the sequential pattern in maximum dive depth. In the daytime, dives were characterized by higher swimming speeds (mean 1.2 m s(-1)) and upward-directed acceleration events. At night, dives were shallower around midnight and characterized by lower speeds (mean 0.9 m s(-1)) and undirectional deceleration events. We suggest that these differences reflect predation on pelagic fishes by seals using visual cues during the day and predation on swarming crustaceans by seals using tactile cues at night.