Date of Award

2022

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Gardiner, Jayne

Area of Concentration

Marine Biology

Abstract

The Manatee River is a non-thermally altered estuarine river that flows into the southern edge of Tampa Bay. Prior studies suggest that temperature and salinity are the primary factors driving juvenile bull shark habitat use. However, previously-studied nurseries at latitudes similar to the Manatee River have been in thermally-altered rivers. The objective was to examine immature bull shark use of this habitat in relation to variation in temperature and salinity. A network of acoustic receivers was deployed within the Manatee River to track movements of acoustically-tagged juvenile bull sharks (n=20). Incorporating data from New College’s temperature/salinity loggers and from USGS stations, the hourly temperature and salinity at each station in the river were modeled. The effect of temperature and salinity on the river distance of bull sharks from the mouth were examined, considering variation due to age. It was found that the bull sharks do overwinter in Manatee River, even though it is not warmed by thermal pollution. Habitat partitioning by salinity between age groups was also observed for sharks aged <1 to 5 years of age. This study also found a much higher salinity preference range for the bull sharks than any previous study in Florida.

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