Evidence for Crassostrea gigas reproduction in the Bizert lagoon of Tunisia SALWA DRIDI1*, MOHAMED SALAH ROMDHANE2, ALEXANDRA LEITAO3 and M'HAMED EL CAFSI1 1 Faculté des Sciences de Tunis, Département de Biologie, Laboratoire de Physiologie de la Nutrition,Campus Universitaire, 1060 Tunis, Tunisia 2 Institut National Agronomique de Tunisie, Département des Sciences de la Production Animale et de la Pêche, 43 Av. Charles Nicole, 1082 Tunis, Tunisia 3 Department of Genetics and Biotechnology, Center for Genetics and Biotechnology of the University of Tras-os-Montes and Alto Douro CGB/UTAD P-5000-911 Vila Real, Portugal Abstract This study reports the first evidence of reproduction of Crassostrea gigas in the Bizert lagoon of Tunisia. The gametogenetic cycle of this species was examined from February 2002 to January 2003 for variation in maturation stage. Environmental parameters such as temperature, salinity, and chlorophyll a concentration were monitored. Initiation of gametogenesis took place in March when water temperature reached 14oC. Ripe oysters were observed in May at a water temperature of 20oC. Spawning began in June and reached a peak in September when water temperature ranged between 23oC and 27oC. During the latter period, oysters presented gonads with ruptured follicles and residual gametes. Spats, from 15 to 20 mm in length, were observed in November 2002 fixed under other oysters. Complementary studies have to be performed, but the present contribution could be of significance for the Tunisian oyster industry, which until now remains dependent on French spat importation.   < back .