Effets de quelques parametres de l'elevage larvaire sur la formation de la vessie natatoire chez les larves de loup : Dicentrarchus labrax (Linne 1758) (Pisces, Serranidae)

Abstract

These experiments were carried out at industrial scale inside a fish hatchery in the south of Tunisia. Results showed that when salinity of rearing water is decreased in the adequate period (from the 5th to 11th day after hatching) the swimbladder rate of sea bass Dicentrarchus labrax larvae increases. At sea water salinity (40ppt), swimbladder rate is around 70%, while when salinity decreased till 22ppt, swimbladder rate increase up to 97%. The second experiment showed that when the surface of rearing water is covered by a fatty film (paraffin oil), swimbladder rate of larvae is very low (0-5%), while without oil on the surface of the rearing tank this rate is around 70%. Therefore, it seems that it's very important to clean the surface of the rearing water to obtain a high quality of larvae