Effects of Salinity on the Reproductive Cycle of the Mangrove Oyster Crassostrea tulipa in Hatchery Conditions

Understanding the e.ects of environmental parameters on the reproductive cycle of shell0sh is an essential tool for successful hatchery conditioning management and, consequently, for seed supply to the industry. For the tropical oyster, Crassostrea tulipa, little is known about the factors a.ecting the maturation process and reproduction, but there are indications that salinity may be of importance. Two experiments were carried out to evaluate the e.ects of salinity on the reproductive cycle of broodstock of C. tulipa. In the 0rst experiment, oysters were reared in 0ve salinities (40, 35, 30, 25, and 20) for 40 days and gonad histological samples were collected regularly. In a follow up experiment, oysters were reared in variable salinity conditions changing from 40 to 30 or from 20 to 30 over a period of 40 days. Salinity was found to a.ect the reproductive cycle of C. tulipa. Oysters kept in constant salinity of 30 showed a higher condition index compared to animals in other salinities, with most of the animals in the prespawning stage. Salinity variation was also shown to a.ect C. tulipa maturation. )e prespawning stage was the most observed reproductive stage in low salinity, and high salinity induced a resting stage in the female animals. )e results are considered the 0rst step towards developing a protocol for the conditioning of C. tulipa in hatchery conditions.