Influence of larval competence periods on coral larval settlement and reef connectivity: a modelling approach

The dispersive larval phase connecting populations on different reefs has important implications for many aspects of coral biology. Larval competence curves describe the proportion of larvae in a cohort available for settling at different times from release. A study of the influence of competency in the settlement and connectivity in coral populations using a spatially realistic model is presented. The model was run using representations of the larval competence period for classical brooders and spawners, and for two spawning species (Acropora valida and Acropora millepora) exposed to random or directional currents. The earlier competence of brooders results in a larger number of larvae settling per larvae produced in all current conditions. The longer competence period of spawners allows them to have a higher absolute connectivity, but this is not necessarily the case when a higher threshold of connectivity is used, especially if the currents are not random. Individual reefs and coral species present very different dynamics, particularly in their connectivity