Size-dependent visual predation risk and the timing of vertical migration: An optimization model
Size-dependent visual predation risk and the timing of vertical migration: An optimization model
复制标题
DOI：
10.4319/lo.2002.47.4.0925
复制
发表时间：
2002-07-01
影响因子：
4.5
通讯作者：
De Robertis, A
中科院分区：
文献类型：
--
作者：
De Robertis, A
浮游动物白天向光照较差的深海栖息地的Diel垂直迁徙(DVM)被认为减少了视觉捕食者攻击的可能性，但代价是净能量收益减少。在这里，我开发了一个权衡模型，用于预测浮游动物垂直迁移的时间。该模型基于“乔里安法则”--即动物会选择死亡风险/能量收益最小的栖息地--并结合了依赖光线和大小的易受视觉捕食者攻击的因素。该模型预测，在广泛的条件下，较小、不那么脆弱的猎物应该比较大、更显眼的生物更早进入食物丰富的表层水域，而下降得更晚。该模型已经被用于不列颠哥伦比亚省萨尼奇湾的太平洋真甲虫种群的参数化，并预测7毫米(幼虫)动物的上升/下降类似于比更明显的24毫米成年动物早/晚35分钟。这些预测与对该人群中DVM发生时间的声学观察相一致。所提出的依赖于大小的DVM计时机制是基于地表水中能量增加的潜力和对大小选择性捕食者脆弱性的潜在变化。这些情况在淡水和海洋中上层环境中都很普遍，依赖于大小的DVM很可能在浮游动物中广泛存在。
Diel vertical migration (DVM) by zooplankton to deep, poorly illuminated habitats during the day is thought to reduce the probability of attack by visual predators at the cost of decreased net energy gain. Herein, I develop a trade-off model used to predict the timing of vertical migration of zooplankton. The model is based on "Gilliam's rule"-the notion that animals will select habitats that minimize the ratio of mortality risk/energy gain-and incorporates light- and size-dependent vulnerability to visual predators. The model predicts that smaller, less vulnerable prey should ascend into food-rich surface waters earlier and descend later than larger, more conspicuous organisms over a wide range of conditions. The model has been parameterized for a population of Euphausia pacifica in Saanich Inlet, British Columbia, and predicts that 7-mm (larval) animals will ascend/descend similar to35 min earlier/later than more conspicuous 24-mm adults. These predictions are consistent with acoustic observations of the timing of DVM in this population. The proposed mechanism for size-dependent timing of DVM is based on the potential for increased energy gain in surface waters and diel changes in vulnerability to size-selective predators. These conditions prevail in both freshwater and marine pelagic environments, and size-dependent DVM is likely to be widespread in zooplankton.