Habitat degradation alters trait-based survival in a coral reef fish

This study investigates the effect of habitat degradation on the interrelationships between morphological, performance, and behavioural traits and their influence on the survival of juvenile Ambon damselfish ( Pomacentrus amboinensis ). The research combined laboratory measurements with field observations on live or degraded coral reefs. Fish behavioural traits were the most important predictors of survival, irrespective of habitat. Specifically, boldness, bite rate, and maximum distance ventured from the patch reef were key factors. However, the relative importance of specific traits differed between habitats. On live coral, relative lateralization was a significant predictor of survival. In contrast, for fish on dead-degraded coral, routine swimming speed and fast-start response latency were more important. Damselfish in degraded habitats experienced significantly higher mortality. These results indicate that habitat degradation alters the selective pressures on phenotypic traits. This study highlights the importance of considering context-dependent trait selection when predicting how fish communities will respond to changing habitat conditions. Additionally, our findings provide insights for restocking and restoration interventions, suggesting that behavioural conditioning that promotes risk-averse behaviours and predator recognition could improve the survival of reseeded fishes.