Observations on the foraging behaviour of adult broodstock European sea bass, Dicentrarchus labrax (L. 1758) in captivity and conceptualisation for the farming of the species

The European sea bass, Dicentrarchus labrax, is a high market value marine and coastal species which feeds on small fish (TORTONESE, 1986). It inhabits coastal waters between 10 and 100 m in the Mediterranean, Black Sea and the European and African Atlantic coasts (North to Scandinavian waters and South to Morocco) (MOREIRA et al., 1992; LLORIS, 2002). It is an important species for the Mediterranean market with high nutritional value (123 kcal/100 This paper presents experimental results on the voracity and foraging behaviour of the European sea bass, Dicentrarchus labrax adults kept in captivity fed a commercial broodstock feed suitable for the species. The results show that the species is a very aggressive predator even after 2 decades of captivity actively competing for food. The primary sensory stimulus to attack the food particles is vision. The number of food particles in the water also affect the foraging behaviour of the fish. As the number of pellets offered simultaneously increases from 10 to 50, so increases the number of missed attempts to consume the particles as well as the number of collisions between individuals attempting to consume the same particle. However, when the number of pellets is more than 30, the dispersion caused by the fish movements is greater and the fish are able to consume more pellets in one pass and therefore, the amount of pellets is consumed sooner. Conceptualising our results for the Mediterranean farming of the sea bass, we consider that its foraging behaviour as described in his paper should be considered as an indicator of good welfare of the farmed fish. In addition, the species foraging behaviour may have important undesirable side effects such as the infliction of trauma due to biting between fish during collisions as well as the loss of food particles through the cage nets during feeding due to the turbulence the fish create by attacking the food particles and missing.