Finding links between sound production and behaviour in the meagre, Argyrosomus regius

Dana Nolte

The meagre, Argyrosomus regius, is a teleost fish belonging to the Sciaenidae family. The members of this family are known to be very vocal, especially during the mating season. This species has been exploited economically for centuries and has been overfished for the last decades, resulting in declining population numbers. There is limited knowledge on the life history of the meagre, especially in the wild, making it a difficult species to protect and monitor. Hence, this thesis aims to provide information about life history and breeding patterns. The main focus lies on meagre behaviour performed before, during and after spawning and its linkage to the production of acoustic signals. Sound production by small juveniles was additionally addressed to investigate the onset of sound production.

Behavioural observations and sound recordings allowed to establish that the onset of sound production occurs between 25 and 30 cm for the studied meagre population. The relation between sound production and behaviour was investigated in adult breeding fish. We found that most calls made during the mating season are likely contact calls relevant to maintain group cohesion in breeding aggregations. Besides, no significant change was found in the occurrence and duration of behaviours before and after the first spawning event of the season.