Date of Award
Open Access Dissertation
Marine turtles have long endured population declines and face a growing number of contemporary threats, highlighting the need for population assessments and conservation action. Research on these species, however, remains a challenge due to complex and extensive oceanic life cycles that hinder direct observation. The pelagic, post-hatchling life stage is particularly difficult to track, preventing empirical research of fundamental behavior and life history traits such as natal homing precision and time to sexual maturity. Also, much of our current knowledge of marine turtles comes from nesting females and hatchlings, stages of the life cycle that are easy to observe. Far less is known about the male component of populations. Here, I use genetic approaches to target these gaps in knowledge by assessing 1) hawksbill turtle rookery structure for Antigua and Barbuda (AB) and the Caribbean, 2) kin structure within Antigua’s Jumby Bay (JB) hawksbill rookery, a population with demonstrated nest-site fidelity and neophyte assimilation, and 3) paternal contributions to nests. Surprisingly strong population genetic differentiation between AB nesting groups suggests that hawksbills migrate back to natal sites with high precision (
colonization potential of island rookeries. Consequently, the current state of alarming deterioration and instability of nesting habitat poses a greater threat to island rookeries relative to those on continuous coastline. The time elapsed between first nesting records of veteran JB mothers and their sexually mature daughters suggests that maximum time to maturity is 14-24 years, shorter than previously estimated for hawksbills. Finally, 24 paternal genotypes were reconstructed from 23 females and their hatchling cohorts, indicating a nearly equal sex ratio for the JB breeding population. Paternal contributions to nests suggest that single paternity is common for Eastern Caribbean hawksbill nests, a finding consistent with hawksbill paternity studies from other regions.
Levasseur, K. E.(2019). Population and Kin Structure of Hawksbill Turtles: Insights on Natal Homing Precision, Time to Maturity and the Male Component of the Breeding Population. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/5587