Complexity of domoic acid-related sea lion strandings in Monterey Bay, California: foraging patterns, climate events, and toxic blooms
Complexity of domoic acid-related sea lion strandings in Monterey Bay, California: foraging patterns, climate events, and toxic blooms
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DOI：
10.3354/meps08816
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发表时间：
2010-01-01
影响因子：
2.5
通讯作者：
Gulland, Frances
中科院分区：
文献类型：
--
作者：
Bargu, Sibel;Silver, Mary;Gulland, Frances
在美国加州蒙特雷湾，硅藻类产生的神经毒素软骨藻酸（DA）是导致海洋哺乳动物和鸟类死亡的主要原因。在这项研究中，我们研究DA相关搁浅的季节性迁移加州海狮Zalophus californianus和区域发生DA生产硅藻使用长达十年的时间序列之间的联系。结果表明，搁浅的模式比预期的更复杂，一个不只是与区域丰富的毒素生产者。搁浅模式的海狮表现出急性DA中毒的迹象，可能是最好的解释多种致病因素，包括时间的有毒水华相对于海狮繁殖周期，充分的海狮猎物在繁殖季节，以及地理范围以外的繁殖季节。1998年、2000年和2007年，蒙特雷湾发生了三次与DA有关的搁浅事件，当时海湾出现了有毒的DA水华，加州海岸正在经历厄尔尼诺/南方涛动。繁殖地附近的觅食中心可能为个体提供了不足的食物，导致这些高度移动的捕食者向北移动到其他地理位置，导致暴露于有毒的DA产生的水华。高毒性假菱形藻和DA浓度没有，但是，导致DA相关的搁浅事件在2002年，2003年和2004年，当弱于正常的上升流事件出现在海湾。相对生产力的中部与南部的加利福尼亚州的繁殖季节，因此似乎强烈影响频率的DA相关搁浅在加利福尼亚州蒙特雷湾。
The neurotoxin domoic acid (DA) produced by the diatoms Pseudo-nitzschia has been responsible for deaths of marine mammals and birds in Monterey Bay, California, USA. In this study we examined links between DA-related strandings of the seasonally migratory California sea lion Zalophus californianus and regional occurrences of DA-producing diatoms using a decade-long time series. Results suggest a more complex pattern of stranding than anticipated, one not related simply to regional abundance of the toxin producers. Stranding patterns of sea lions exhibiting signs of acute DA toxicosis may be best explained by multiple causative factors including timing of toxic blooms with respect to the sea lion breeding cycle, adequacy of sea lion prey during the breeding season, as well as the geographic range of this pinniped outside of the breeding season. Three DA-related stranding events occurred in Monterey Bay in 1998, 2000 and 2007, when toxic DA blooms were present in the Bay and the California coast was experiencing El Nino/Southern Oscillation conditions. Foraging centers near the breeding site likely provided inadequate food for individuals, leading to northerly movement of these highly mobile predators to other geographic sites resulting in exposure to toxic DA-producing blooms. High toxic Pseudo-nitzschia and DA concentrations did not, however, result in DA-related stranding events in 2002, 2003 and 2004, when weaker than normal upwelling events were present in the Bay. Relative productivity of central versus southern California with respect to the breeding season thus appears to strongly influence the frequency of DA-related strandings in Monterey Bay, California.