Historic over-exploitation and the more recent threats caused by fisheries by-catch, disease and climate change have left sea turtle populations in the Wider Caribbean at risk of extinction. In 1995, following regional declines in nesting and foraging populations, the island of Anguilla implemented a moratorium on the hunting of turtles. At the request of the Government of Anguilla for scientific data to either support or remove the moratorium, comprehensive population estimates were obtained, and foraging, nesting and migratory movements were examined. In addition, community perspectives on turtles and their protection were assessed. Between 2015 and 18 surveys of 30 nesting beaches estimated low nesting activity with a maximum of 41 hawksbill, 15 green, and 1-2 leatherback turtles nesting in Anguilla annually. The inter-nesting range of hawksbills exhibited high levels of geographic overlap and occurred within 1.5 km of nesting beaches. Migratory tracks of hawksbill turtles traversed through seven exclusive economic zones, two of which allow a legal turtle fishery. Site fidelity was observed in foraging areas of green turtles and genetic analysis revealed population differentiation between green turtle foraging sites in Anguilla and between hawksbill rookeries in Anguilla compared to other Leeward Islands, indicating the individual importance of each foraging and nesting site. The Anguillan public (n = 302) overwhelmingly agreed with the current ban on harvesting sea turtles and considered turtles important for ecotourism. Our work provides a case-study, that can be applied globally, of how scientific research combined with community perspectives can effectively inform policy and ultimately protect endangered species, and highlights that local Governments provided with high quality data in a timely fashion for their policy making timetable are more likely to integrate findings into their decision-making process.

The geographic specificity of natal philopatry (how precisely breeding individuals return to their natal origins) influences breeding biology, genetic diversity and habitat range, and therefore has important implications for species resiliency and management. Also, the age at which individuals reach sexual maturity and enter the breeding population is a vital parameter for demographic analyses. Empirical research on philopatry and maturation, however, is challenging for long‐lived animals that are difficult to observe, such as marine turtles that have complex oceanic life histories. Regional natal philopatry is well established for marine turtles, but the geographic specificity of philopatry is unclear. Similarly, estimates of age at maturity vary widely, and direct evidence is lacking. Here, we targeted these information gaps by assessing kinship among 256 females from Antigua’s Jumby Bay (JB) hawksbill turtle rookery, a population with demonstrated nest‐site fidelity and neophyte assimilation. We estimated mother–daughter and full sibling relationships with a maximum‐likelihood full‐pedigree reconstruction approach, incorporating genotypic (12 microsatellites), maternal genealogy (mitochondrial DNA) and age structure (long‐term mark–recapture) data. We validated relationships with parentage assignment and pairwise relatedness estimators. Fourteen veteran nesters were the mothers of 42 younger nesters, and 94 nesters formed 35 full sibships. Time between the first nesting records of mothers and their daughters indicated maximum time to maturity as short as 14 years in Caribbean hawksbills. Thirteen of the 14 mothers showed consistently high fidelity to JB for two decades, providing compelling evidence that 41 of these daughters originated from JB nests and returned to this 1‐km‐long natal site to breed. Rookeries with strongly philopatric individuals might have limited colonization potential and be at a disadvantage in the event of habitat loss. This study demonstrates the utility of long‐term mark–recapture data in kinship analyses for answering questions relevant to endangered species conservation.

Marine turtles migrate back to their natal region during reproduction, but the precision of this homing behavior and how the precision varies among populations and across biogeographic regions are unclear. We hypothesize that marine turtles nesting on insular landmasses navigate to their rookeries with greater precision than those nesting on continuous coastlines. We analyzed new mitochondrial and microsatellite marker data from hawksbill turtles Eretmochelys imbricata at nesting sites across Antigua and Barbuda, West Indies, to assess the scale of natal homing in the highly insular Leeward Islands. We then used published data from 15 western Atlantic rookeries to examine regional patterns of rookery structure. Mitochondrial control region data showed weak to no partitioning among nesting sites within Antigua and strong partitioning between Antigua and Barbuda, suggesting natal homing at a scale of 50 km. Microsatellite data showed weak to no partitioning between sites, indicating male-mediated gene flow. Regionally, we found stronger population structuring among rookeries of insular landmasses than among those of larger landmasses with continuous coastlines, despite shorter average rookery separation for the former. We also found a positive relationship between a rookery's isolation index (a metric incorporating distances from larger landmasses) and its genetic divergence from proximate rookeries. These findings support our hypothesis, and we caution that insular rookeries that host marine turtles with extreme homing behavior have limited ability to colonize new nesting habitat. The unprecedented rates of development and increasing instability of present-day nesting habitat might therefore pose a greater and increasing threat to insular rookeries.