Keywords

Hematology, Wildlife Health, Reproductive Success, Disease, Ontogenetic Shifts

Abstract

Understanding variations in health and immune function across life stages or physiological states is important for population monitoring and for understanding species’ responses to anthropogenic disturbances. Sea turtles are a model species for evaluating these changes within and across life stages due to their long lifespans with ontogenetic habitat and diet shifts. In this dissertation, I tested whether health and immune hematological proxies (Packed Cell Volume [PCV], white blood cell counts, total protein [TP], biochemistry) differed: (1) across the reproductive season, (2) between species and (3) foraging groups, and (4) with reproductive output for adult female turtles (Chapter 2). In Chapter 3, I tested whether these proxies differed (1) between two habitats, (2) across turtle size, (3) water temperatures, (4) disease severity and (5) species for juvenile turtles, and in Chapter 4, (1) across three green turtle (Chelonia mydas) life stages. Overall, I collected blood samples from dispersal stage turtles captured in the Gulf of Mexico (n=22 green), neritic juveniles from near-shore Florida habitats (n=155 green, n=40 loggerhead [Caretta caretta]), and females (n=120 green, n=122 loggerhead) nesting in Florida between 2020 and 2023. For chapters 2 and 3, multivariate linear regression models were used to evaluate relationships between collective proxies and predictors for adult females and neritic juveniles; generalized linear mixed models were used to evaluate relationships between reproductive output (Chapter 2) and size/disease severity/temperature (Chapter 3) across proxies. Chapter 4 used generalized additive models (GAM) and hierarchical GAMs to evaluate relationships between proxies across life stages. In Chapter 2, I found potential species-specific immune strategy differences during nesting; these differences likely related to migration distance and foraging habitat location. In Chapter 3, I found that smaller turtles with severe disease states had stronger fluctuations in hematological values compared to non-diseased turtles, especially during colder months. Across life stages (Chapter 4), I found hematological differences that align with green turtle ontogenetic habitat and diet shifts particularly for neritic juveniles. This dissertation provides insight into ontogenetic shifts, health across physiological states, and species comparisons for northwest Atlantic sea turtle populations. Building off these results, additional studies evaluating anthropogenic stressors and health and immune function are important for establishing conservation targets and monitoring population health, particularly during periods of environmental change.

Completion Date

2025

Semester

Fall

Committee Chair

Mansfield, Katherine

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Biology Department

Format

PDF

Identifier

DP0029766

Document Type

Thesis

Campus Location

Orlando (Main) Campus

Download

Share

COinS