Lasala, Jacob

Sound assessment of the status of a threatened or endangered organism depends on understanding
key aspects of behavior throughout its life history. Sometimes organisms can be difficult to observe and
key aspects of behavior may not be accessed directly. Alternative assessment techniques include using
molecular markers to identify fundamental relationships among males and females. In the context of
assessing the status of imperiled populations’ sex ratios, population size and the relatedness of the
individuals are important metrics. Environmental sex determination directs developing marine turtle sex
so that primary sex ratios depend upon weather and climate; those sex ratios are estimated by proxies.
Adult population sizes are inferred from numbers of females nesting on the beach, but numbers of
males are unknown. Male breeding population size can be estimated from subtracting maternal
genotypes from genotypes of offspring exclusion analyses. The resulting adult sex ratios differ greatly
from those estimated for hatchlings. To refine current adult sex ratios in ways that are relevant to
production of future generations and add to our understanding of effective population size we compare
the breeding sex ratios the number of males and females contributing to a population of three species
of sea turtles nesting in southern Florida. We will use the same genetic data to measure relatedness of
the female nesters and the male contributors and describe how that relates to genetic flow and
population structure.

Characterizing a species mating system is integral to understanding its natural history and is critical to the development of effective conservation strategies. A mating system is typically described by examining a single population and subsequently drawing inferences on the whole of the species. Variation among populations and gaps in understanding of a species often are revealed when studies are compared between several locations. The majority of available marine turtle mating system data stem from nesting females or hatchlings scurrying off the beach. This practice left glaring holes in the understanding of these imperiled organisms in particular with respect to males. We use exclusion paternity analysis to compare the genotype of a nesting female with genotypes from a subset of her offspring and deduce male genotypes to identify and count the number of males contributing per clutch. Loggerheads Caretta caretta, green turtles Chelonia mydas and tleatherbacks Dermochelys coriacea are protected species with spatially and temporally overlapping nesting beaches. The genotypes of the three species nesting in southern Florida will be compared among clutches to define mating systems. Additionally, we will provide the first measure of operational population size for both males and females in southern Florida. Finally, by comparing results from several beaches, the interconnectedness of rookeries through male-mediated gene flow will be determined as well as the relatedness of males. Our approach to establishing the mating systems of hard-to access-life stages will have strong conservation value in strengthening the demographics that form the core of species assessment and management.