Kevin Jensen

Date of Award

2017

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Gardiner, Jayne

Area of Concentration

Marine Biology

Abstract

This study was the first to quantitatively survey Sarasota Bay as a potential shark Essential Fish Habitat (EFH) as mandated by the Magnuson-Stevens Act of 1996. Research was part of the Gulf of Mexico Shark Pupping and Nursery (GULFSPAN) survey. Prior to the 1990’s, Sarasota Bay’s ecosystem was affected by anthropogenic pollution and water management strategies. The U.S. Congress established Sarasota Bay as an Estuary of National Significance in 1989 and restoration efforts have improved water quality and increased seagrass coverage. Standardized gillnet surveys were used to sample nekton. One hundred and seventy-eight sharks were caught comprising 5 species. The dominant species was Sphyrna tiburo (90.4%) followed by Rhizoprionodon terraenovae (5.6%), Sphyrna lewini (1.7%), Carcharhinus limbatus (1.7%), and Carcharhinus acronotus (0.6%). forty-two percent of sharks were immature. Each species had comparable abundances as other documented nurseries. Temporal data of S. tiburo were normally distributed centered in July. Finding comparable abundances of shark species provided preliminary evidence for support of Sarasota Bay as a nursery habitat and as EFH by satisfying the short-term criteria of a nursery habitat. The definition of a nursery area obliges sampling to consistently show comparable abundances over many years.

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