High activity and Levy searches: jellyfish can search the water column like fish
High activity and Levy searches: jellyfish can search the water column like fish
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DOI：
10.1098/rspb.2011.0978
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发表时间：
2012-02-07
影响因子：
4.7
通讯作者：
Sims, David W.
中科院分区：
文献类型：
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作者：
Hays, Graeme C.;Bastian, Thomas;Sims, David W.
过度捕捞可能导致鱼类数量减少和水母繁殖。主动运动和寻找猎物可能被认为为鱼类提供了竞争优势，但在这里，我们使用数据记录器来显示频繁出现的沿海水母（根口章鱼）并不仅仅是被动地漂移来遇到猎物。水母（每1分钟收集25只水母327天的深度数据）表现出非常动态的垂直运动，它们的综合垂直运动平均为619.2 m d(-1)，是它们被标记的水深的60多倍。大多数的运动模式是最接近的指数模型描述正常随机行走。然而，水母也表现出从指数模式切换到截断Levy分布最适合的模式的行为，该分布的指数（平均mu = 1.96，范围1.2-2.9）接近寻找稀疏猎物的理论最优值（mu（opt）近似于2.0）。这些“简单”动物的复杂动作可能有助于水母与鱼类有效地竞争浮游生物猎物，这可能会增强它们在受干扰的海洋系统中增加优势的能力。
Over-fishing may lead to a decrease in fish abundance and a proliferation of jellyfish. Active movements and prey search might be thought to provide a competitive advantage for fish, but here we use data-loggers to show that the frequently occurring coastal jellyfish (Rhizostoma octopus) does not simply passively drift to encounter prey. Jellyfish (327 days of data from 25 jellyfish with depth collected every 1 min) showed very dynamic vertical movements, with their integrated vertical movement averaging 619.2 m d(-1), more than 60 times the water depth where they were tagged. The majority of movement patterns were best approximated by exponential models describing normal random walks. However, jellyfish also showed switching behaviour from exponential patterns to patterns best fitted by a truncated Levy distribution with exponents (mean mu = 1.96, range 1.2-2.9) close to the theoretical optimum for searching for sparse prey (mu(opt) approximate to 2.0). Complex movements in these 'simple' animals may help jellyfish to compete effectively with fish for plankton prey, which may enhance their ability to increase in dominance in perturbed ocean systems.