Date of Award

12-12-2017

Document Type

Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

First Advisor

Robert F. Young

Second Advisor

Juliana M. Harding

Third Advisor

Keshav Jagannathan

Abstract

Of the three estuarine bottlenose dolphin stocks in South Carolina, two are considered data insufficient, with no minimum population estimate or assigned potential biological removal value. Additionally, the Northern Georgia Southern South Carolina Estuarine System (NGSSCES) stock’s boundaries are based on sighting data that do not extend to the full area encompassed by the boundary lines. In areas where stock boundaries are not clearly defined and data is insufficient for traditional methods of estimating abundance, density may provide insight into local distributions and serve as a proxy for actual abundance. Photo-identification surveys were conducted in three sites, representative of the two data insufficient estuarine stocks, between March 2012 and February 2013. Linear density (dolphins/km transect) was similar for all three sites (p=0.0773) and resident dolphins made up between 15.45% and 23.61% of total individuals within each site. Additionally, there was no movement of individuals between study areas, specifically between the two sites that make up the NGSSCES stock. These patterns provide evidence that estuarine bottlenose dolphins in South Carolina share similar characteristics regardless of stock designation, and that the NGSSCES stock might be comprised of smaller, independent communities or sub-populations. Current management approaches for estuarine bottlenose dolphin stocks in South Carolina are problematic due to the uncertainty of stock boundaries and abundance. If future studies continue to identify small groups of dolphins with strong site fidelity or small home ranges such as in this study, the traditional stock concept might need to be re-evaluated with management efforts shifting toward simple measures of linear density to determine relative abundance.

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