Etude de l'influence de facteurs internes et externes sur la reproduction de poissons marins en captivité

This work describes the results of some esperiments carried out on the effect of the temperature, the photoperiod, the spawners food regime and other biotic factors upon the captive brood stock of Sea Bass (Dicentrarchus labrax), Turbot (Scophtalmus maximus), Sole (Solea solea), Gilthead Sea Bream (Sparus aurata and Red Mullet (Mullus surmuletus). The results clearly show that ail the above species spawn naturally in captivity conditions. A number of spawns can be obtained in tanks where only one species or a pool of species is maintained under natural or artificial temperature and photoperiod, with fish receiving différent types of food diet and in tanks of varying capacity. The characteristics of each spawn varies according to the following factors : - The spawning season : it can be either naturally or artificially induced through the photoperiod and temperature pattern input in the tanks. - The total number of eggs per spawn : it is related to both the female physiological condition and the spawners' environmental parameters such as temperature and photoperiod. - The egg size and viability : the temperature seems to determine the egg diameter,and the overall egg viability seems to be related to the diet and to the capacity of the tanks. Nevertheless, no clear relation was found between the egg hatching rate and the environmental and physiological conditions of the spawners.