Predators can exert strong ecological effects on their prey either via consumption or by altering their behaviour and morphology. In marine systems, predators and their prey co‐occur in a three‐dimensional environment, but to date predator–prey studies have largely focussed on behaviours of prey on horizontal (distance from shelter) rather than vertical (height in water column) axes. We used life‐size shape‐models of a blacktip reef shark Carcharhinus melanopterus (threatening shape‐model), a juvenile coral trout Plectropomus leopardus (non‐threatening shape‐model) and a shape‐control to examine the impact of perceived instantaneous (measured by time to first feeding) versus sustained (measured by time to consume the entire bait) predation threats on the feeding behaviour and three‐dimensional use of space by mesopredatory reef fishes in a coral reef environment. We found that mesopredatory fishes such as red snapper Lutjanus bohar and spangled emperor Lethrinus nebulosus took longer to begin feeding and to consume predation assays (fish baits) at greater distances from the shelter of a patch reef across both horizontal and vertical axes and that this phenomenon was stronger in the vertical axis than the horizontal. The presence of a life‐size shape‐model of a shark, which we used to increase the perception of predator threat, magnified the instantaneous effect compared to non‐threatening models, but not the sustained effect. We found no evidence for a difference in the level of predation risk posed by the shape‐model of the juvenile coral trout (a non‐threatening reef fish) and a negative control (no shape‐model). Our study suggests that mesopredators modify their behaviours in response to the perceived risk of predation across both horizontal and vertical axes away from shelter, and that this response is most severe on the vertical axis, potentially limiting daytime foraging behaviour to a hemisphere around shelter sites.

中文翻译：

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恐惧的半球：鲨鱼的存在影响着珊瑚礁生态系统中大型中捕食者的三维行为

捕食者可以通过食用或改变其行为和形态，对猎物产生强大的生态影响。在海洋系统中，捕食者及其猎物在三维环境中同时发生，但是迄今为止，捕食者－猎物的研究主要集中在水平（距避难所的距离）而不是垂直（水柱高度）轴上的猎物行为上。我们使用了与黑鳍礁鲨（Carcharhinus melanopterus）（威胁的形状模型），幼体鳟鱼Plectropomus leopardus一样大小的形状模型。（非威胁性形状模型）和形状控制，以检查感知的瞬时（按第一次进食时间测量）与持续（按消耗整个诱饵的时间测量）捕食威胁对进食行为和三维的影响珊瑚礁环境中的中层礁鱼利用空间。我们发现了中捕性鱼类，例如红鲷鱼Lutjanus bohar和亮片的皇帝Lethrinus nebulosus在横轴和纵轴上距礁石掩体的距离较大的地方，开始摄食和消耗捕食化验（鱼饵）的时间更长，并且这种现象在纵轴上比水平方向更强。与非威胁模型相比，我们用来增强对捕食者威胁的感知的真人大小鲨鱼形状模型的存在放大了即时影响，但没有持续影响。我们没有证据表明，幼体鳟鱼（非威胁性的礁鱼）的形状模型和阴性对照（无形状模型）构成的捕食风险水平存在差异。我们的研究表明，中等偏见者会改变其行为，以应对在远离庇护所的水平轴和垂直轴上掠食的风险，