Stable Isotopic Dynamics of Juvenile Elasmobranchs in a South Carolina Nursery Area

Christian J. Pankow^1,*, Catherine C. Macdonald^1,2, David S. Shiffman⁴, Julia Wester^1,3, and Dan Abel⁵

¹Field School, 3109 Grand Avenue #154, Miami, FL 33133. ²Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149. ³Abess Center for Ecosystem Science and Policy, University of Miami, 1365 Memorial Drive, Coral Gables, FL 33146. ⁴Arizona State University New College of Interdisciplinary Arts and Science, 4701 W Thunderbird Road, Glendale, AZ 85306. ⁵Coastal Carolina University, Department of Coastal and Marine Systems Science, Coastal Carolina University, PO Box 261954, Conway, SC 29528. *Corresponding author.

Southeastern Naturalist,Volume 20, Issue 1 (2021): 92–104

Abstract
Stable isotope analysis is an increasingly utilized method for understanding resource usage and partitioning in marine species, including elasmobranch fishes. While the diet of elasmobranchs in Winyah Bay, SC, has been the subject of some preliminary research, diet and trophic relationships in this ecosystem are not yet well understood. This study addresses these knowledge gaps using δ13C and δ15N stable isotope analysis to increase understanding of isotopic niche breadth and overlap among 128 individuals representing 11 sympatric elasmobranch species present in Winyah Bay during the summer months. Overall, our findings support an understanding of Winyah Bay’s elasmobranch community as trophically diverse, with some significant isotopic niche overlap among considered species, suggesting the possibility of competition for resources between co-occurring small elasmobranchs. These results suggest elasmobranch predators in the Winyah Bay ecosystem have complex and varied predator–prey relationships.

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