Elevated CO(2) Affects Predator-Prey Interactions through Altered Performance

Recent research has shown that exposure to elevated carbon dioxide (CO(2)) affects how fishes perceive their environment, affecting behavioral and cognitive processes leading to increased prey mortality. However, it is unclear if increased mortality results from changes in the dynamics of predator-prey interactions or due to prey increasing activity levels. Here we demonstrate that ocean pCO(2) projected to occur by 2100 significantly effects the interactions of a predator-prey pair of common reef fish: the planktivorous damselfish Pomacentrus amboinensis and the piscivorous dottyback Pseudochromis fuscus. Prey exposed to elevated CO(2) (880 µatm) or a present-day control (440 µatm) interacted with similarly exposed predators in a cross-factored design. Predators had the lowest capture success when exposed to elevated CO(2) and interacting with prey exposed to present-day CO(2). Prey exposed to elevated CO(2) had reduced escape distances and longer reaction distances compared to prey exposed to present-day CO(2) conditions, but this was dependent on whether the prey was paired with a CO(2) exposed predator or not. This suggests that the dynamics of predator-prey interactions under future CO(2) environments will depend on the extent to which the interacting species are affected and can adapt to the adverse effects of elevated CO(2).