Sexual reproduction of the coral Pocillopora damicornis in the southern Gulf of California, Mexico

Pocillopora damicornis, one of the dominant coral species in reef systems of the eastern Pacific, presents geographic variation in its reproductive mode. There is no information, however, on the reproduction of this species in the Mexican Pacific, and such knowledge is relevant since the populations are in active recovery after bleaching and mortality caused by the 1997-98 El Nino event. In this study we determined the reproductive pattern of P. damicornis from histological analyses of ramets collected at Punta Gaviotas (24.5 degrees N), southwestern Gulf of California, Mexico. Our results indicate that R damicornis is a hermaphroditic species with simultaneous development of female and male gametes. Four developmental stages were denoted for each type of sexual cell, corresponding to those defined in studies conducted elsewhere in the eastern Pacific. Gametes were observed from June to November (summer/fall) 2001 and from May to July 2002. No planulae were found, although mature oocytes and spermatozoa (stage IV) were detected during a five-month period (July to November) in 2001, and in June and July 2002. This finding indicates the occurrence of reproductively active populations of P. damicornis in the Gulf of California that broadcast gametes. The occurrence of ova and sperm was synchronous during the warm season, and thus temperature most likely controls the reproductive periodicity of this species. Maternal inheritance of zooxanthellae was observed, as well as the presence of gametes in early and late developmental stages in different colonies but in the same month.