INTRODUCTION OF AN EXOTIC CONSTRICTING SNAKE (BOA CONSTRICTOR) AND ITS ESTABLISHMENT ON ST. CROIX, US VIRGIN ISLANDS

The introduction of boas from the pet trade to novel localities poses a threat to sub-tropical and tropical islands worldwide. The first constricting snake was found on St. Croix, U.S. Virgin Islands, in 2012. Despite efforts to work locally to remove snakes from the environment, we found increasing numbers of individuals each year, and we removed 88 boas from the wild on St. Croix through August 2018. We used spatial and genetic analyses to determine the range and origin of Boa Constrictors (Boa constrictor) on St. Croix, which is not native to St. Croix. We found that individuals were genetically identical with an origin in the Gulf of Mexico. We conclude that the boas are from a single source, or even a single founding female, originating in the pet trade. The boas have spread exponentially to occupy > 50% of the island since their introduction. We recommend strategies to eradicate non-native snakes on St. Croix including education, monitoring of native species, regulation, removal, and research.