Cycle sexuel des femelles de sandre Stizostedion lucioperca (L.,1758) Pisces, Percidae dans la retenue du barrage de Sidi Salem (Tunisie)

Abstract

Between March 1996 and March 1997, a study on sexual maturity was led on a sample of 720 females of pikeperch Stizostedion lucioperca living inSidi Salem reservoir located in the north of Tunisia. Beside, a histological study including a microscopic observation of the oocyte maturity, was led on 65 females. These two studies showed that the age of first sexual maturity is one year for the females of pikeperch in Tunisia (length was 24 cm and weight was 90 g). On the other hand, the spawning period is mainly influenced by the temperature. In fact, it begins by the end of february and lasts to the second half of march when the temperature is close to 14 degree C. The relative fecondity is about 200 eggs/ g of female body weight and the absolute fecondity F is highly linked to the weight W (F=632* W 0.77), to the length L (F=6760*L -148372) and to the age t (F= 83791*t - 60373). Finally, histological observation displayed a synchronous ovogenesis which allowed a simultanous unique spawning of pikeperch population in the considered reservoir.