Food deprivation reduces social interest in the European sea bass Dicentrarchus labrax

Abstract

Periods of food deprivation up to several months are common features for fishes and in such conditions, fitness will be determined by their capacity to maximize food encounter while minimizing predation risk. In this context, the propensity to take risk and the willingness to associate with conspecifics are particularly important as they contribute to alleviating the trade-off between predation avoidance and foraging efficiency. This study examined to what extent food deprivation modulates fish risk-taking and social behaviours, as well as the relationship between them. To address these issues juvenile European sea bass were either fed daily with a maintenance ration or food-deprived during 3 weeks. Risk-taking and sociability were assessed through measurements of fish willingness to explore a novel environment, to interact with a novel object or a conspecific. Multivariate analysis allowed the identification of three behaviours, risk-taking, exploratory activity and solitariness. Food-deprived fish interacted less with conspecifics than control fish. After food-deprivation, no difference in terms of risk-taking and exploratory patterns was observed. Finally, the relationship between risky-taking and solitariness was influenced by the feeding status. When food-deprived fish with higher propensity to take risk displayed increased solitariness while, when fed normally they interacted more with conspecifics.