Second, modeling survival rates without first parameterizing rates for a null model devoid of change in age structure or annual nest counts encourages statistical artefacts. First, size/age structure of stranded sea turtles traditionally derives modeled survival rates 9 but variable cohort recruitment and/or demographic changes also influence observed structure 16. Given that Kemp’s ridley sea turtles typically achieve sexual maturity in their first decade 13, researchers anticipated a far more robust increase in annual nesting than what transpired 14, 15.Ī recent stock assessment for Kemp’s ridley sea turtles 14 reported strong influence of anthropogenic mortality sources on nesting, but further scrutiny revealed methodology concern. Despite conservation in this region since 1966, through 2022, nest counts remain ≤ 23% 9 of the lower 1947 estimate 10. Recent re-analysis of video data from the 1947 arribada also suggests that Kemp’s ridley sea turtles laid between 82,514 and 209,953 nests in 1947 12. Initially estimated to comprise 40,000 nesters 10, subsequent investigations later suggested the 1947 arribada comprised between 6,000 11 and nearly 30,000 nesters 12. The oldest quantified nesting reference in Tamaulipas, Mexico stems from an “arribada” nesting event on 18 June 1947 10. Most annual nesting for this species occurs in the western Gulf of Mexico (GOM) in the state of Tamaulipas, Mexico 9. In contrast to green and loggerhead sea turtles in the Americas since the 1990s, managers exercise a more cautious interpretation of annual nest count data 9 for the Kemp’s ridley sea turtle ( Lepidochelys kempii ). Concurrent with decades of conservation, nest counts for green sea turtles ( Chelonia mydas) in the Pacific Ocean 6 and Caribbean 7 and loggerhead sea turtles ( Caretta caretta) in the Northwest Atlantic Ocean 8 now exhibit stable to increasing trends. Other trawl fisheries later adopted similar in-water protective measurements 4 and reducing incidental capture in other fisheries remains a global priority 5. In-water protection began in the 1990’s following the deduction that drowning in shrimp trawls posed the greatest anthropogenic threat to sea turtles residing in nearshore coastal waters of the Southeast United States 3. Legislative acts initially protected sea turtles on nesting beaches but also prohibited their trade. In wildlife management, balancing protections with optimizing resource use remains existential.įor the past six decades, human perceptions of global sea turtle species have mostly shifted from a commodity for consumption 1 to a flagship conservation species with economic value 2. These novel findings provide alternative perspective for evaluating species recovery criteria and in turn refine future nest trend expectations. Across 32 models, high survival and dynamic cohort sex ratio, sexual maturity age, and the ratio of clutch frequency to remigration interval best explained nesting trends during 1966–2022. In objectives 3 and 4, a simulator modeled population response to changes in a suite of demographic rates including survival. r 2 = 0.82) and hatchlings per nest (adj. In objective 2, multiple regression revealed a lagged (≤ 13 years prior) climate influence on nests (adj. In objective 1, improved analysis of the ratio of hatchlings to nests since 1966 suggested age structure stabilization as a more likely basis for nest count trends after 2005 than density-dependent effects. Prior studies attribute less robust than anticipated nest count rebound to multiple contemporary concerns however, analyses herein convey optimistic interpretation. Despite > 50 years of dedicated conservation, annual nest counts remain well below a landmark 1947 level. For at least two decades preceding conservation, high egg harvest rates reduced annual cohort recruitment. Restricted range, and subsequently small population size, render Kemp’s ridley sea turtles ( Lepidochelys kempii) the most globally endangered sea turtle species.
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