Date of Award

2022

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. James Watling

Abstract

Human use of oceans has dramatically increased in the 21st century, with some of the highest rates of change found within the Gulf of Mexico and Caribbean. Sea turtles are particularly vulnerable to anthropogenic stressors in the marine environment as they make lengthy migrations between foraging and breeding sites often along coastal migration corridors. Sea turtles face severe population pressure from humans, yet little is known about how movement and threats interact specifically for male sea turtles. To better understand male sea turtle movement, and the threats they encounter within their expansive ranges, we tagged 40, adult male sea turtles of four different species. We calculated movement patterns using state-space modeling (SSM) and quantified threats in seven unique categories: shipping, fishing, light pollution, oil rigs, proximity to coast, marine protected area (MPA) status, and location within or outside of the US Exclusive Economic Zone (EEZ). We found multiple clusters of male sea turtles within the Gulf of Mexico and Caribbean, with significantly higher threat severity in northern and southern latitudes for green turtles and Kemp’s ridleys. These threats are pervasive, with only 35.9% of SSM points encountering no high threat exposure, of which 47% belong to just two individuals. We also found Kemp’s ridleys were most exposed to high threats among tested species. Lastly, turtles within MPA boundaries face significantly lower threat exposure, supporting the use of MPAs within the United States (US) as a conservation tool.

Available for download on Saturday, April 29, 2023

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