Range-wide population genetic structure of the Caribbean sea fan coral, Gorgonia ventalina

The population structure of benthic marine organisms is of central relevance for the conservation and management of these often threatened species as well as an accurate understanding of their ecological and evolutionary dynamics. A growing body of evidence suggests that marine populations can be structured over short distances despite theoretically high dispersal potential. Yet the proposed mechanisms governing this structure vary, and existing empirical population genetic evidence is of insufficient taxonomic and geographic scope to allow strong general inferences. Here we describe the range-wide population genetic structure of an ecologically important Caribbean octocoral, Gorgonia ventalina. Genetic differentiation was positively correlated with geographic distance and negatively correlated with oceanographically-modeled dispersal probability throughout the range. Although we observed admixture across hundreds of kilometers, estimated dispersal is low, and populations can be differe...