Strong Population Genetic Structure in the Southern Stingray, Dasyatis americana, Revealed by mtDNA Control Region Sequences

Although over half of all known elasmobranchs are batoids, with many species exploited and several of conservation concern, little is known of their population genetic structure and intraspecific evolutionary history. We report here an assessment of gene flow among geographic populations of the southern stingray ( Dasyatis americana ), a large, recreationally important, demersal batoid that ranges from New Jersey, USA and the northern Gulf of Mexico to southern Brazil. Sequence variation in 648bp of the mitochondrial control region was used to infer patterns of gene flow among Florida and Caribbean populations. Out of 229 animals sampled from six locations, 56 haplotypes were identified and AMOVA results revealed high levels of population structure (overall ST=0.47). Gene flow between the Everglades National Park, Florida, and Antigua separated by 2,200km was highly restricted (ST=0.82). Restricted gene flow was also apparent over much shorter geographic distances, as a comparison between two Belizean populations separated by just 120km produced a ST of 0.21. Our results highlight that populations of the southern stingray need to be managed as distinct evolutionary units.