Growth parameters, instantaneous mortality rates (Z, F and M), yield per recruit and biomass per recruit of the oyster Crassostrea rhizophorae were estimated using the FiSAT package, based on shell length frequency data of 2551 individuals. Von Bertalanffy growth parameters and total mortality were estimated using the ELEFAN I program and the catch curve method, respectively. Pauly's and M = 2K empirical equations were used to estimate natural mortality. Values found are L∞ = 149 mm, K = 0.9 year-1, Φ′ = 4.3 and t0 = -0.05 year-1, respectively. Age at entry is too low because of the harvest of small oysters attached to the adults shells. Total, natural and fishing mortalities were estimated at 5.16, 2.0 and 3.16 year-1, respectively. The exploitation rate (0.6) and fishing mortality indicate that oyster is slightly overexploited due mainly to the harvest method used by fishermen rather than to the increase of effort itself. Yield per recruit could be substantially improved by returning shells to the environment.