Background/Question/Methods Maintaining genetic diversity is crucial to the survival and management of threatened and endangered species. In this study we analyzed the genetic diversity and population genetic structure of five American crocodile, Crocodylus acutus, populations (Las Baulas, Santa Rosa and Palo Verde National Parks, Rio Tarcoles and Area of Conservation Osa) along the Pacific coast of Costa Rica. Nine microsatellites were used to genotype 183 individuals and investigate genetic diversity and gene flow measures.

Results/Conclusions

We found that no population was at Hardy-Weinberg Equilibrium over all loci tested and a small to moderate amount of inbreeding present. All populations were significantly differentiated from each other with both F_ST and R_ST measured of population differentiation. We observed a total of 2.4 effective migrants per generation along the entire coast and the presence of population structure. The coast segregated into three populations using a model-based clustering analysis. An effective management plan that maintains the connectivity between populations is critical to the continued success of Crocodylus acutus in Costa Rica.