The presence of multiple predators can lead to variation in predator behavior and ultimately altered risk for shared prey. This concept has seldom been accounted for in studies that consider predator-driven biotic resistance from native marine predators against invasive prey. This study compared the prey selection of whelks and rock lobsters when co-occurring and when foraging in isolation. When in isolation, both predators preferred the native mussel Choromytilus meridionalis, regardless of the abundance of alternative prey. However, when co-occurring, predation risk for all prey species, including the invasive mussel Semimytilus algosus, increased. This was largely driven by greater variation in prey selection by rock lobsters in the presence of whelks. This indicates that predatory efforts from co-occurring predators can result in stronger predation pressure on invasive prey than would be recognized if predators were assessed in isolation.

多个捕食者的存在会导致捕食者行为发生变化，并最终改变共享猎物的风险。在考虑本地海洋捕食者对侵入性捕食者的捕食者驱动的生物抗性的研究中，很少考虑到这一概念。这项研究比较了同时出现和单独觅食时的鲸和龙虾的猎物选择。孤立时，两个捕食者都喜欢原生贻贝Chromytilus meridionalis，而不管其他猎物是否丰富。但是，当同时发生时，所有捕食物种（包括侵入性贻贝Semimytilus algosus）的捕食风险， 增加。这主要是由于有龙虾的情况下，龙虾对猎物的选择变化较大。这表明，与孤立评估掠食者相比，共生掠食者的掠夺努力会导致对侵入性猎物的更大捕食压力。