Shut up or shout loudly: Predation threat and sound production in fishes

Predation is a major ecological constraint shaping behaviour and communication in animals. Several fish species are known to modify their foraging, agonistic and reproductive behaviour in the presence of predators. However, close to nothing is known about how predators affect sound production in fishes. This paper reviews how vocal fish increase their chance of survival by modifying intraspecific acoustic communication and by producing sounds directed towards predators. Field studies showed that toadfish, drums and squirrelfish reduced the number and loudness of calls when dolphin sounds were played back. These studies lack behavioural observations, leaving the question open how individual fish respond to predation threat. Croaking gouramis (Trichopsis vittata, Osphronemidae) reduced acoustic and visual signalling during dyadic contests and refrained from escalated behaviour when detecting a predator in an adjacent tank. This indicates that gouramis increase their vigilance by reducing agonistic behaviour. Vocal fish have been observed to emit sounds when predators approach or when being caught. However, none of the predators (or even conspecifics nearby) responded to these calls. Therefore, the term predator-related sound has been introduced in this paper to avoid implying unproven functions (alarm, startling, warning, distress and disturbance). Interestingly, the readiness of numerous taxa (e.g. catfishes) to vocalize when hand-held or netted was frequently exploited to investigate sound production in fish in relation to weight, sex, sonic organs, temperature or phylogeny. Increasing levels of noise in aquatic habitats call for more research on predator-prey interactions because of potential negative effects on detection of sounds produced by predators or prey.

Automated summary

Predation plays a crucial role in shaping behavior and communication in animals, including fish. While some fish species modify their vocalizations in the presence of predators to increase survival chances, the specific effects of predators on sound production in fish remain largely unknown. This paper reviews how fish adjust their acoustic communication to predators and highlights the importance of further research on predator-prey interactions in noisy aquatic environments.