Little is known about the impact of ocean acidification on predator–prey dynamics. Herein, we examined the effect of carbon dioxide (CO2) on both prey and predator by letting one predatory reef fish interact for 24 h with eight small or large juvenile damselfishes from four congeneric species. Both prey and predator were exposed to control or elevated levels of CO2. Mortality rate and predator selectivity were compared across CO2 treatments, prey size and species. Small juveniles of all species sustained greater mortality at high CO2 levels, while large recruits were not affected.
Ocean acidification is one of the most pressing environmental concerns of our time, and not surprisingly, we have seen a recent explosion of research into the physiological impacts and ecological consequences of changes in ocean chemistry. We are gaining considerable insights from this work, but further advances require greater integration across disciplines. Here we showed that projected near-future CO2 levels impaired the ability of damselfish to learn the identity of predators.