REPRODUCTIVE-CYCLE OF THE CUTTLEFISH, SEPIA-OFFICINALIS (L) IN THE NORTHERN PART OF THE BAY-OF-BISCAY

The sexual cycle of the cuttlefish, Sepia officinalis, from the northe rn part of the Bay of Biscay was followed over several years (1988 to 1990 and 1992 to 1993). Successive maturity stages are reached at the same time regardless of site in the northern part of the Bay. In this area, the majority of cuttlefish reproduce during their second year of life (group II) whereas the remainder reproduce in their first year ( group I). The first visible signs of sexual development concern the te stis in males and the genital tract in females. Males mature earlier t han females: the first spermatophores appear in July (group II) and Oc tober (group I) while mature eggs appear from December (group II) and March (group I). The breeding season lasts from about mid-March to lat e June (3.5 months).