Fine scale population structure of and in the Colombian Caribbean.

Using a standardized SNP array, we identified two populations of and one population of in the Caribbean coast of Colombia. San Andrés was the most genetically differentiated location for both species. An average pairwise F value of 0.131 and 0.050 between San Andrés and neighboring collection sites was estimated, for and respectively. Based on population patterns of both acroporid species, we inferred that Magdalena River is not a barrier of genetic connectivity among Colombian populations. Genetic comparisons between the Colombian coast of Caribbean with other Caribbean locations agree with previous studies for both species where four populations were identified in and three in Our results support published bio-physical model predictions and highlight the Panama-Colombia gyre as a possible isolating mechanism within the western Caribbean. However, the genetic diversity in both species was about half (mean HE per site = 0.321 in and 0.369 in ) than previous estimates in acroporid populations in the Caribbean. The lower genetic diversity as well their relative isolation and high levels of reef degradation may be of particular conservation concern that may require species-specific management coupled with science-based restoration efforts.