Reef coral reproduction in the eastern Pacific: Costa Rica, Panama, and Galapagos Islands (Ecuador). 3. Agariciidae (Pavona gigantea and Gardineroseris planulata)

• Published in: Marine biology 1996-05, Vol.125 (3), p.579-601
• Main Authors: Glynn, P W, Colley, S B, Gassman, N J, Black, K, Cortes, J, Mate, J L
• Format: Article
• Language: English
• Subjects: Gardineroseris planulata; Marine; Pavona gigantea
• ISSN: 0025-3162

The reproductive ecology of Pavona gigantea and Gardineroseris planulata was investigated in the equatorial eastern Pacific region from 1985 to 1994. These zooxanthellate scleractinian corals were adversely affected in this region during the 1982-1983 El Nino warming event. Both species were hermaphroditic, with individual colonies showing sequential cosexual development, thus resulting in dominantly outbreeding reproduction. Sexuality was mixed, with high percentages of gonochoric and hermaphroditic colonies in both species. Approximately 1:1 male-to-female gonad ratios were found in gonochoric and hermaphroditic colonies combined. Broadcast spawning was observed in P. gigantea in the Galapagos Islands, and the sudden disappearance of mature gametes and the presence of spent gonads suggest that G. planulata is also a broadcast spawner. Colonies of both species with less than or approximate to 200 cm super(2) (10 cm diam) live tissue were nonreproductive. Estimated ages of the youngest reproductive colonies were 11 yr for P. gigantea and 20 yr for G. planulata. The percentage of all colonies of P. gigantea with gonads at nonupwelling sites (Cano Island, Costa Rica and Uva Island, Panama) ranged from 37 to 47%, respectively; colonies with gonads from upwelling environments (Saboga and Taboga Islands, Panama) ranged from 31 to 39%, respectively, and reproductively active colonies from the thermally variable Galapagos Islands comprised 40% of the collections. Compared with P. gigantea, the numbers of sexually active G. planulata colonies were roughly onehalf at nonupwelling Cano Island (20%) and Uva Island (25%) sites, or less (10%) at the upwelling Saboga Island site. Peak reproductive activity in P. gigantea occurred during the rainy season at all study sites. In the nonupwelling Costa Rican (Cano Island) and Panamanian (Uva Island) sites, mean monthly sea-surface temperatures (SSTs) were high (28 to 29 degree C), but slightly lower than in the dry season (29 degree C). In the upwelling Gulf of Panama (Saboga and Taboga Islands), reproduction occurred after mean monthly SSTs increased from 24 to 28-29 degree C. In the Galapagos Islands, reproductive activity peaked during sea warming, when mean monthly SSTs reached 25 degree C. Sexually active colonies of G. planulata, present only at the main collection sites of Cano and Uva Islands, were also observed during the wet season. The presence of mature or spawned gonads in both species mostly around new and ful