Environmental conditions and Equatorial Eastern Pacific coral reproductive phenology in the Gulf of Panamá (Pavona gigantea and Psammocora stellata)

Abstract This is the first study in a series that analyzes environmental conditions associated with the Intertropical Convergence Zone (ITCZ) and coral reproductive success at regional equatorial eastern Pacific (EEP) sites. Established gametogenic trends of Pavona gigantea (hermaphroditic, massive colonies) and Psammocora stellata (dioecious, nodular colonies) from the Gulf of Panamá, were regressed (GLMM) with changes in local seasonal factors potentially affecting gametogenesis. These included reef temperature, precipitation, cloud cover, wind, PAR, insolation, and photoperiod. Seasonal transitions are predictors of the initiation or cessation of gametogenesis in the two-season climate. Psammocora gametogenesis was highly associated with all warm-wet season values while Pavona gametogenesis was highly associated with photoperiod and temperature change, but significantly related to all variables tested. PCA compensated for multicollinearity. Early in the year upwelling effects and late wet season effects may limit Pavona reproductivity and mimic a photoperiod trend. Coral gametogenesis was negatively associated with PAR and positively associated with cloud cover, suggesting that excessive PAR may be a limiting factor. Wind speed in forcing upwelling was a key effect, although northerly wind direction may be a better predictor of gamete development. While the rate of temperature change was more influential to Pavona, Psammocora reproduced at a reef temperature threshold of 27.8 °C (monthly mean). Knowledge of timing and environmental conditions affecting the sexual reproduction of corals sheds light on their resilience and their capacity to recover and is critically important now during accelerated global reef decline. Such information will support efforts directed toward coral reef rehabilitation and conservation.