Using Half-Weight Association Index to Analyze Stock Boundaries of South Carolina Estuarine Bottlenose Dolphins, Tursiops truncatus

Presentation Type

Event

Full Name of Faculty Mentor

Robert Young

Major

Marine Science

Presentation Abstract

Bottlenose dolphins, Tursiops truncatus, are protected by the Marine Mammal Protection Act (MMPA, 16 U.S.C.). Estuarine bottlenose dolphins in South Carolina are currently classified into three stocks: the Northern South Carolina Estuarine System (NSCES) Stock, the Charleston Estuarine System (CES) Stock, and the Northern Georgia/Southern South Carolina Estuarine System (NGSSCES) Stock. The boundaries of these stocks were determined based on the extent of early surveys and have not been systematically investigated. This study uses the half-weight association index between dolphins surveyed in the three estuarine stock regions to examine whether the distribution of discrete groups of associated dolphins correlates with established stock boundaries. Six mark/recapture photo-identification surveys, comprising a total of 2,750 km on effort, were conducted in estuarine waters of South Carolina between May and early October, 2017. Each survey took approximately 7 days to complete and covered the entire range of the NSCES and CES stocks and part of the NGSSCES stock. Dorsal fin images and survey data were managed using FinBase, and only fins meeting criteria for distinctiveness and photo quality were used for analysis. Association indices were calculated for all dolphins sighted at least three times. Three clusters of associated dolphins will be identified and their distribution will be examined relative to the current stock boundaries.

External Presentation

1

Location

Brittain Hall, Room 101

Start Date

17-4-2019 2:10 PM

End Date

17-4-2019 2:30 PM

Disciplines

Oceanography

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Apr 17th, 2:10 PM Apr 17th, 2:30 PM

Using Half-Weight Association Index to Analyze Stock Boundaries of South Carolina Estuarine Bottlenose Dolphins, Tursiops truncatus

Brittain Hall, Room 101

Bottlenose dolphins, Tursiops truncatus, are protected by the Marine Mammal Protection Act (MMPA, 16 U.S.C.). Estuarine bottlenose dolphins in South Carolina are currently classified into three stocks: the Northern South Carolina Estuarine System (NSCES) Stock, the Charleston Estuarine System (CES) Stock, and the Northern Georgia/Southern South Carolina Estuarine System (NGSSCES) Stock. The boundaries of these stocks were determined based on the extent of early surveys and have not been systematically investigated. This study uses the half-weight association index between dolphins surveyed in the three estuarine stock regions to examine whether the distribution of discrete groups of associated dolphins correlates with established stock boundaries. Six mark/recapture photo-identification surveys, comprising a total of 2,750 km on effort, were conducted in estuarine waters of South Carolina between May and early October, 2017. Each survey took approximately 7 days to complete and covered the entire range of the NSCES and CES stocks and part of the NGSSCES stock. Dorsal fin images and survey data were managed using FinBase, and only fins meeting criteria for distinctiveness and photo quality were used for analysis. Association indices were calculated for all dolphins sighted at least three times. Three clusters of associated dolphins will be identified and their distribution will be examined relative to the current stock boundaries.