A study conducted by the University of Liège has uncovered new information on the use of acoustic communication by fish in the context of harassment behaviour towards a predator. This research (1), focusing on a species of Holocentridae (Sargocentron caudimaculatum), shows that these fish produce specific sounds when they gather together to harass a moray eel, their natural predator.
T
he acoustic harassment (mobbing) behaviour of a predator has been observed and documented for several years. Instead of fleeing, prey surround the predator while emitting sounds. This tactic is thought to destabilise the predator, which, unable to concentrate on a particular prey, abandons the attack. Like other organisms such as birds and mammals, fish display defensive behaviour in groups when faced with a threat. However, the association of sound production with this behaviour had only been reported once in fish 60 years ago (2), without any control experiment and with an inadequate description of the sounds produced.
In order to test the existence of these behaviours in fish, researchers from the Functional and Evolutionary Morphology Laboratory at ULiège designed an aquarium experiment to observe the behavioural and acoustic response of Sargocentron caudimaculatum to the introduction of a moray eel. The study confirmed that these fish gather around the moray eel in a harassing behaviour. "In a novel way, the study revealed a significant increase in the production of sounds called 'staccatos' when the predator was introduced," explains Marine Banse, a marine biology researcher. These sounds, stereotypical of harassment behaviour, were only produced in the context of the presence of a real moray eel, and not with a plastic moray eel used in control conditions."
© Université de Liège / M.Banse
The ULiège study makes a significant contribution to our understanding of fish defence mechanisms via acoustic communication. "This discovery highlights the fact that acoustic communication in fish is not limited to territorial defence or reproduction. Like many terrestrial animals, fish also use sound to transmit messages between different species, which involves complex interactions. This observation reveals that the social abilities of fish are much more highly developed than we previously thought. There is communication between fish living in the same environment", concludes Eric Parmentier, director of the Laboratory specialising in the study of fish vocalisations.
The results obtained by Marine Banse and her colleagues are part of the young researcher's thesis on the evolutionary patterns of acoustic communication in Holocentridae, which aims to evaluate and clarify the different types of sound produced by these fish, and to integrate phylogenetic and morphological data to establish an evolutionary scenario for their acoustic communication.
(1) Banse Marine, Minier Lana, Lecchini David, Parmentier Eric, Acoustic mobbing behaviour: vocal fish responses to predation risk through sound communication, Marine Biology, june 2024 - DOI 10.1007/s00227-024-04455-w
(2) Winn, H. E., Marshall, J. A. & Hazlett, B. Behavior, diel activities, and stimuli that elicit sound production and reactions to sounds in the longspine squirrelfish. Copeia 1964, 413-425 (1964).
A new European project on the downstream behavior of Atlantic salmon smolts on a long stretch of the Ourthe river basin is starting within the Management of Aquatic Resources and Aquaculture Unit.
The Biological Oceanography Laboratory is involved in the PIONEER project, which aims to identify and quantify the effects of noise and chemical pollution on cetacean hearing in the Arctic.
Ce Prix, d’un montant de 1.500 euros, récompensera un·e chercheur·euse dont l'ancienneté doctorale est inférieure à 3 ans au 1er janvier 2025, qui se sera distingué·e par la publication d’un mémoire original (master ou doctorat) réalisé à l’ULiège.
