Date of Award

5-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Wildlife and Fisheries Biology

Advisor

Yarrow, Greg K

Committee Member

Dozier , Jamie

Committee Member

Layton , Pat

Abstract

Sea turtles are one of the most recognizable and charismatic marine species worldwide that continue to be the focus of many conservationists. However, their populations and habitat continue to decline at an alarming rate due to predation, development, pollution, rising sea levels, beach erosion, and commercial fishing. Consequently, maximizing nest production in current nesting regions is fundamental to sea turtle recovery efforts. On the southeastern coast, coyotes (Canis latrans) and sea turtles have a relatively new relationship, but the presence of this latest predator has dramatically reduced sea turtle nesting success in certain areas. An active predator management strategy for coyotes will promote and support sea turtle recovery goals.
The Tom Yawkey Wildlife Center (TYWC), located off the coast of South Carolina is a sanctuary for marine turtles with pristine, undisturbed beaches. In South Carolina the Department of Natural Resources (SCDNR) is responsible for managing beaches that support nesting habitat for threatened and endangered sea turtles. The TYWC is composed of North, Cat, South and Sand Islands which provides an ideal area for researching sea turtle predation. In South Carolina the most common sea turtle is the loggerhead (Caretta caretta), which averages approximately 300 nests each summer on the TWYC (Griffin 2011). The first coyote appeared on TWYC in 2006 and their populations continued to flourish on the islands. In 2009, coyotes on South Island were responsible for 52% of the total loggerhead sea turtle egg loss which is equivalent to approximately one third of South Carolina's documented egg loss for that year (SCDNR 2010). Coyotes tend to depredate nests on the initial night of oviposition and this has made daily surveys ineffective as a management strategy. As a result, the SCDNR is examining alternative management practices to decrease coyote-induced sea turtle depredation.
Specific objectives to address the project goals are to 1) determine the effectiveness of night patrols in reducing coyote predation on loggerhead sea turtle nests 2) develop an infrared camera survey to determine if coyote predation on post-emergence hatchlings is an additional mortality and 3) determine the presence or absence of coyotes around loggerhead sea turtle nests and hatchlings. In 2010, scheduled night patrol surveys were conducted, which ultimately reduced the amount of nest depredation from a staggering 52% in 2009, to 15%. The first coyote predation was successfully documented on post-emergence sea turtle hatchlings utilizing infrared cameras. These results were used to calculate the overall estimated decrease in hatchling productivity.
Following the first season in the winter of 2010, trapping and removal of coyotes was completed on South Island beach. These management strategies decreased the total amount of coyote presence on the beaches and lead to a nest depredation rate of only 2.6% for the entire 2011 season. Based on the results of this study, recommendations are provided for reducing coyote predation on sea turtle nests and hatchlings throughout the Southeast.

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