Sexual reproduction by the Caribbean reef corals Montastrea annularis and M. cavernosa

Abstract

Montastrea annularis is hermaphroditic, with an annual gametogenic cycle that begins in May and ends with spawning in August and/or September. M. cavernosa is dioecious, with a prolonged oogenic cycle that begins in November, a briefer spermatogenic cycle that begins in May, and spawning events during July, August and/or September. Spawning for both species appears to occur c1wk after the full moon. Both species delay reproduction until colony size reaches c100cm2 in surface area. In M. annularis, but not in M. cavernosa, polyps in the middle of the colony have greater reproductive activity than those near edges of the colony. Ripe gonads of M. annularis account for 30-40% of the biomass of sexually mature polyps. Assuming 10-50% bottom cover by this species, spawning releases 8.4-44g C m-2 and 0.9-4.7g N m-2 to the reef water column on one or two nights yr-1. The failure of sexual recruits of M. annularis to appear on Caribbean coral reefs cannot be attributed to lack of reproductive effort. -from Author