Diel periodicity in both sei whale vocalization rates and the vertical migration of their copepod prey observed from ocean gliders
Diel periodicity in both sei whale vocalization rates and the vertical migration of their copepod prey observed from ocean gliders
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DOI：
10.4319/lo.2008.53.5_part_2.2197
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发表时间：
2008-09-01
影响因子：
4.5
通讯作者：
Fratantoni, David M.
中科院分区：
文献类型：
--
作者：
Baumgartner, Mark F.;Fratantoni, David M.
海洋捕食者的日常活动周期可能在很大程度上取决于猎物可用性的时间。例如，最近的研究观察到须鲸发声率的昼夜周期性，认为这是由其动物性猎物的昼夜垂直迁移所决定的。我们解决了这一假设，通过研究协会之间的sei鲸鱼（Balaenoptera borealis）发声率，海洋条件，和鲸鱼的猎物，哲水蚤桡足类哲水蚤finmarchicus的垂直分布，在2005年5月在西南部的缅因州湾使用一系列自主的海洋滑翔机。四架滑翔机中的每一架都配备了传感器来测量温度、盐度和叶绿素荧光。四架滑翔机中有三架携带数字声学记录器，第四架携带1 MHz声学多普勒海流剖面仪。我们在海流剖面仪测得的声波后向散射中观察到强烈的昼夜周期性，我们将其归因于（基于一项确证的船上研究）C。finmarchicus。塞伊鲸的发声率也表现出昼夜周期性，在白天检测到更多的呼叫时，C。在深海观察到finmarchicus。我们没有发现任何证据表明，所观察到的模式sei鲸鱼调用率是由于昼夜周期性的背景噪音或声传播条件。塞氏鲸善于在近水面聚集的C。因此，我们认为鲸鱼是在夜间进食的。我们假设，呼叫率在晚上减少，而鲸鱼喂养，但增加与社会活动在白天，桡足类动物是更困难或更有效地捕捉在深度。滑翔机在研究期间经历的恶劣天气条件下的持续性允许对鲸鱼发声行为和海洋学条件进行连续的并置观察，这在以前是不可能用传统的船上技术实现的。
The daily activity cycles of marine predators may be dictated in large part by the timing of prey availability. For example, recent studies have observed diel periodicity in baleen whale vocalization rates that are thought to be governed by the diel vertical migration of their zooplanktonic prey. We addressed this hypothesis by studying associations between sei whale (Balaenoptera borealis) vocalization rates, oceanographic conditions, and the vertical distribution of the whales' prey, the calanoid copepod Calanus finmarchicus, during May 2005 in the southwestern Gulf of Maine using an array of autonomous ocean gliders. Each of the four gliders was equipped with sensors to measure temperature, salinity, and chlorophyll fluorescence. Three of the four gliders carried a digital acoustic recorder and the fourth carried a 1-MHz acoustic Doppler current profiler. We observed strong diel periodicity in the acoustic backscatter measured by the current profiler that we attribute (based on a corroborating shipboard study) to the diel vertical migration of C. finmarchicus. Sei whale vocalization rates also exhibited diel periodicity, with more calls detected during the daytime when C. finmarchicus was observed at depth. We found no evidence to suggest that the observed patterns in sei whale calling rates were attributable to diel periodicity in background noise or acoustic propagation conditions. Sei whales are adept at foraging on near-surface aggregations of C. finmarchicus; therefore we expect that the whales were feeding at night. We hypothesize that calling rates are reduced at night while the whales are feeding, but increase with social activity during the day when copepods are either more difficult or less efficient to capture at depth. The gliders' persistence during adverse weather conditions experienced during the study allowed continuous collocated observations of whale vocalization behavior and oceanographic conditions that have not been previously possible with traditional shipboard techniques.