Abstract
Predation is one of the strongest forces shaping animal behaviour, yet the role of acoustic communication in predator detection by coral reef fish remains poorly understood. We investigated the acoustic and behavioural antipredator responses of the banded humbug damselfish, Dascyllus aruanus, exposed to models of a predator (coral trout, Plectropomus leopardus), non-predatory fish (convict surgeonfish, Acanthurus triostegus and surf parrotfish, Scarus rivulatus), and controls (PVC pipe and transparent Perspex), at Lizard Island, Great Barrier Reef. Sheltering behaviour showed a hierarchical threat sensitive pattern: fish were seven times more likely to shelter in the presence of a predator than in control treatments. Grouping increased in response to any fish model (predatory and non-predatory) compared to controls, indicating a social response to non-specific elevated risk. Damselfish were more likely to produce sound in the presence of a predator than when exposed to a non-predator or controls, suggesting that vocalisation is sensitive to perceived predation threat. Furthermore, acoustic activity and sheltering were positively associated, suggesting that sound production might play a role in coordinating group defences. Our findings advance our understanding of the role of acoustics in predator recognition and avoidance in fishes.