Assessing behaviour and welfare of European seabass (Dicentrarchus labrax) in sea-cages through acoustic telemetry

Abstract

[eng] Acoustic telemetry is a remote sensing method that utilises acoustic signals to monitor fish behaviour. This study demonstrates the applicability of acoustic telemetry techniques to monitor the welfare of European sea bass (Dicentrarchus labrax) in grow-out cages. It analyses their behavioural patterns and responses (swimming activity and vertical distribution) across different temporal scales, in relation to environmental conditions in open sea and intrinsic aquaculture procedures. The experimental cages were located in Port d'Andratx, at the Laboratory of Marine Research and Aquaculture (LIMIA-IRFAP). Twenty individuals fitted with acoustic transmitters, implanted through surgical procedures, were monitored during four months using three receivers to capture transmitter signals and generate the dataset analysed. Data analysis was conducted in R-Studio 4.3.3., employing ANOVA tests to assess hourly differences and mixed-effects linear models to examine daily variations. Correlation analyses explored the relationships between the primary parameters of swimming activity and spatial distribution with various environmental factors of interest. This study demonstrates that acoustic telemetry techniques are feasible tools that enable monitoring of seabass behaviour in captivity, providing insights into their responses to various stimuli, events, or procedures that may affect their welfare. That kind of information is very useful to enhance the accuracy, precision, and repeatability of farming operations to improve fish health and welfare, while increasing productivity, performance, and sustainability of aquaculture.