Gonadal cycle of Pteria sterna (>Gould, 1851) (Mollusca, Bivalvia) in Baja California, Mexico

Histological analyses were conducted on 376 organisms of Pteria sterna obtained from an experimental raft located in the Bay of los Angeles, Baja California, Mexico. From August 1987 to August 1988, seven bimonthly samplings were made that covered animals from two to fourteen months of age. We propose a gonadal cycle with seven maturity phases and a histological scale of sexual maturity with nine conspicuous stages. The age of first maturity occurred in the females in October and in the males in December. Based on the observations, it is concluded that the population of P. sterna, settled on the experimental raft in August 1987, spawned continuously, with peaks in December, February and August.