Variability in fin whale (Balaenoptera physalus) occurrence in the Bering Strait and southern Chukchi Sea in relation to environmental factors
Variability in fin whale (Balaenoptera physalus) occurrence in the Bering Strait and southern Chukchi Sea in relation to environmental factors
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DOI：
10.1016/j.dsr2.2020.104782
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发表时间：
2020-07-01
影响因子：
3
通讯作者：
Laidre, Kristin L.
中科院分区：
文献类型：
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作者：
Escajeda, Erica;Stafford, Kathleen M.;Laidre, Kristin L.
长须鲸(Balaenoptera Physalus)是夏季常见的北极太平洋游客，它们通过白令海峡迁徙到楚科奇海南部，以季节性丰富的猎物为食。楚科奇海长须鲸的数量和分布每年都有所不同，这可能反映了环境条件的波动。我们推测，长须鲸的叫声最有可能出现在年份和多产水团出现的地点，这表明低温和高盐度，以及强烈的向北的水和风速，导致猎物平流增加。利用2009-2015年白令海峡地区三个停泊水听器的声学记录，我们识别了开放水域季节(7-11月)长须鲸的叫声，并调查了长须鲸存在年际变化的潜在环境驱动因素。我们研究了近地表和近海底温度(T)和盐度(S)，通过海峡的风和水的速度，根据公布的T/S边界估计的水团存在，以及卫星得出的海表面温度和海冰密度。我们的结果显示，长须鲸的声音存在显着的年际变异性，在环境条件不同的年份(2012年和2015年)，检测到的叫声最多。2012年，气温更低，盐度更低，水流速度更慢，南风更弱，而2015年气温更高，盐度更高，水流速度更快，南风适中。大多数检测(96%)发生在最靠近营养丰富的Anadyr和白令架水团汇合处的系泊地点，类似于白令海峡以北35公里处，这表明生产性水团可能影响长须鲸的发生。2012年和2015年之间环境条件的差异表明，可能存在多种环境因素或其他未经检查的变量组合，将长须鲸吸引到太平洋北极。
Fin whales (Balaenoptera physalus) are common summer visitors to the Pacific Arctic, migrating through the Bering Strait and into the southern Chukchi Sea to feed on seasonally-abundant prey. The abundance and distribution of fin whales in the Chukchi Sea varies from year-to-year, possibly reflecting fluctuating environmental conditions. We hypothesized that fin whale calls were most likely to be detected in years and at sites where productive water masses were present, indicated by low temperatures and high salinities, and where strong northward water and wind velocities, resulting in increased prey advection, were prevalent. Using acoustic recordings from three moored hydrophones in the Bering Strait region from 2009-2015, we identified fin whale calls during the open-water season (July-November) and investigated potential environmental drivers of interannual variability in fin whale presence. We examined near-surface and near-bottom temperatures (T) and salinities (S), wind and water velocities through the strait, water mass presence as estimated using published T/S boundaries, and satellite-derived sea surface temperatures and sea-ice concentrations. Our results show significant interannual variability in the acoustic presence of fin whales with the greatest detections of calls in years with contrasting environmental conditions (2012 and 2015). Colder temperatures, lower salinities, slower water velocities, and weak southward winds prevailed in 2012 while warmer temperatures, higher salinities, faster water velocities, and moderate southward winds prevailed in 2015. Most detections (96%) were recorded at the mooring site nearest the confluence of the nutrient-rich Anadyr and Bering Shelf water masses, similar to 35 km north of Bering Strait, indicating that productive water masses may influence the occurrence of fin whales. The disparity in environmental conditions between 2012 and 2015 suggests there may be multiple combinations of environmental factors or other unexamined variables that draw fin whales into the Pacific Arctic.