Annual variation in the foraging behaviour of thick-billed murres in relation to upper-ocean thermal structure around St. George Island, Bering Sea
Annual variation in the foraging behaviour of thick-billed murres in relation to upper-ocean thermal structure around St. George Island, Bering Sea
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DOI：
10.3354/ab00243
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发表时间：
2010-01-01
期刊：
影响因子：
1.4
通讯作者：
Watanuki, Yutaka
中科院分区：
文献类型：
--
作者：
Kokubun, Nobuo;Takahashi, Akinori;Watanuki, Yutaka
我们研究了觅食行为的成年厚嘴海乌利亚lomvia，因为他们饲养他们的小鸡在圣乔治岛，阿拉斯加，美国，相对于附近的海洋水柱的热结构在2004年，2006年和2007年夏天使用数据记录器连接到鸟类。上层海洋的热结构在不同年份之间变化很大。2004年卫星测得的海表温度和水深大于40米的水温高于2006年和2007年（平均海表温度分别为9.1、8.3和7.8摄氏度;中位底层温度分别为5.1、4.4和2.2摄氏度）。我们在2004年和2007年记录到了一个很强的温跃层，但在2006年没有。尽管如此，在所有年份中，Thermodine都是重要的觅食栖息地之一。厚嘴海的觅食行为似乎随温跃层强度和水深水温的年度变化而变化，并明显与猎物的垂直分布相关。2004年和2007年，鸟类花了更多的时间在分层的沃茨觅食，并潜入温跃层深度附近（2007年更深）。然而，在2006年，这些鸟使用分层和混合沃茨，不太可能潜入温跃层深度。主要猎物项目交付给小鸡不同年份。2004年，沙矛鱼（占观察到的鱼类的53%）和鳕鱼（23%）占主导地位，而2006年，头足类动物（23%）、比目鱼（17%）和鳕鱼（15%），以及2007年头足类动物（62%）、鳕鱼（16%）和杜父鱼（9%）。
We studied the foraging behaviour of adult thick-billed murres Uria lomvia as they reared their chicks at St. George Island, Alaska, USA, relative to the thermal structure of the nearby ocean water column in the summers 2004, 2006, and 2007 using data recorders attached to the birds. The thermal structure of the upper ocean varied substantially among the years. Satellite-derived sea surface temperature (SST) and water temperature at depths >40 m were higher in 2004 than in 2006 and 2007 (9.1, 8.3 and 7.8 degrees C for mean SST; 5.1, 4.4, and 2.2 degrees C for median bottom temperature, respectively). We recorded a strong thermocline in 2004 and 2007, but not in 2006. Nonetheless, the thermodine was one of the important foraging habitats in all years. The foraging behaviour of thick-billed murres appeared to vary with annual variation in the intensity of the thermocline and water temperature at depth and evidently with associated vertical distribution of prey. Birds spent more time foraging in stratified waters and dived to around thermocline depth (and deeper in 2007) in 2004 and 2007. However, the birds used both stratified and mixed waters in 2006 and were less likely to dive to thermocline depth. Main prey items delivered to chicks varied among years. Sand lance (53% of observed items) and pollock (23%) predominated in 2004, compared with cephalopods (23%), flatfishes (17%) and pollock (15%) in 2006, and cephalopods (62%), pollock (16%) and sculpins (9%) in 2007.