The escape behaviour of sea bream (Sparus aurata l.) in relation with the stocking density.

Fish escape from sea cages present an environmental and economical problem. In the present work the escape behaviour of sea bream was studied in three experiments. In each experiment, the effect of three different stocking densities was tested: low (L): 4.5- 5kg/m3, medium (M): 6.5-7kg/m3 and high (H): 8.5-9kg/m3. Ιn the first experiment the mesh was flawless in the second a single twine was cut, while in the third a large tear was created. Fish behaviour as well as fish interactions with the mesh were recorded and analysed by means of a pilot recording-analyzing methodology developed for this purpose. In the first experiment the time spent for exploration or biting the mesh was in relation to the stocking density. In the second experiment, fish were found to spend at least 50% more time biting the mesh. Escapes and returns in experiment three were more frequent at the H stocking density and less frequent at the M.