REPRODUCTIVE CHARACTERISTICS OF THE POLYMORPHIC CARIBBEAN REEF BUILDING CORAL MONTASTREA-ANNULARIS .1. GAMETOGENESIS AND SPAWNING BEHAVIOR

The dominant Caribbean reef coral Montastrea annularis (Ellis & Solander) exists as at least 3 morphotypes of uncertain taxonomic status. I examined reproductive characteristics of the morphotypes (viz.'Bumpy, 'Massive' and 'Columnar'; Van Veghel & Bak 1993, Mar. Ecol. Prog. Ser. 92: 255-265) histologically and studied spawning in the field. The morphotypes all had the same reproductive mode, i.e. individuals were hermaphrodites, gametogenesis was synchronized, and both eggs and sperm matured within the same gonad and were broadcast on the same lunar phases for external fertilization. Spawning in the field on Curacao took place 6, 7 and/or 8 d after full moon in September and October. No differences in spawning time and/or behavior were observed. Gametogenic initiation and spawning took place about 1 mo later on the reefs of Curacao and Bonaire than in most other Caribbean localities. Possible spawning timing cues such as relative seawater temperature, moon phase, and time after sunset were found to be consistent with other spawning observations of this species; tidal regime was not consistent.