Movement patterns and trophic ecology of tiger sharks (<i>Galeocerdo cuvier</i>) caught in the southeast United States
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Edman, Robert Mehnert
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Abstract
Tiger sharks (<i>Galeocerdo cuvier</i>) occupy tropical and temperate waters around the globe, yet the majority of studies on this species’ movement and diet have been focused in the Pacific and Indian oceans. We utilized satellite and acoustic telemetry to track the movement patterns of tiger sharks caught in the western North Atlantic Ocean and stable isotope analysis to study the trophic ecology of these animals. Tiger sharks tagged in this study exhibited individual variation in movement patterns, however overall results indicate sharks primarily utilized and were philopatric to coastal waters of the southeast coast of the United States as opposed to more pelagic waters used by tiger sharks caught in other areas of the western North Atlantic Ocean. Tiger sharks moved primarily in inshore, coastal, and shelf waters along the east coast of the United States during the spring and summer, while some movements farther offshore and south to the Bahamas occurred during the winter. Movements to and from the coastal waters of the United States are likely driven by a combination of water temperature, reproduction, and prey availability. Stable isotope analysis revealed that large mature tiger sharks caught in coastal waters feed primarily on coastal species including rays and small coastal foraging species. The differences observed between tiger sharks caught in South Carolina compared to others in the western North Atlantic Ocean highlights the importance of utilizing multiple tagging locations to fully understand the basin-wide movement patterns of this wide-ranging species.