Evidence for developmental thermal acclimation in the damselfish, Pomacentrus moluccensis

Tropical species are predicted to have limited capacity for acclimation to global warming. This study investigated the potential for developmental thermal acclimation by the tropical damselfish Pomacentrus moluccensis to ocean temperatures predicted to occur over the next 50-100 years. Newly settled juveniles were reared for 4 months in four temperature treatments, consisting of the current-day summer average (28.5 A degrees C) and up to 3 A degrees C above the average (29.5, 30.5 and 31.5 A degrees C). Resting metabolic rate (RMR) of fish reared at 29.5 and 31.5 A degrees C was significantly higher than the control group reared at 28.5 A degrees C. In contrast, RMR of fish reared at 30.5 A degrees C was not significantly different from the control group, indicating these fish had acclimated to their rearing temperature. Furthermore, fish that developed in 30.5 and 31.5 A degrees C exhibited an enhanced ability to deal with acute temperature increases. These findings illustrate that developmental acclimation may help coral reef fish cope with warming ocean temperatures.