Document Type

Thesis

Degree

Master of Science

Department

Biology

Advisor's Name

Michael Heithaus

Advisor's Title

Committee Chair

Advisor's Name

James Fourqurean

Advisor's Name

Maureen Donnelly

Keywords

predator, abundance, habitat use, movement

Date of Defense

7-15-2010

Abstract

The purpose of this study was to investigate whether there is regional variation in the abundance and habitat use of tiger sharks (Galeocerdo cuvier) within in a model seagrass ecosystem. Abundance was determined with catch rates on drumlines and habitat preferences were investigated using acoustic tracking of large tiger sharks (n=4). I found spatiotemporal variation in the probability of catching at least one shark and in catch rates on days sharks were caught. In general, sharks were present throughout more of the year and in higher abundances in the northern region. Habitat use also varied between regions. In the northern region, sharks moved randomly with respect to habitat, while in the southern region sharks preferred shallow habitats. Although preliminary, these results suggest that large predator abundance and habitat use may vary over relatively small spatial scales and that such variation may be useful for elucidating their ecological role.

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