Date of Award

Spring 2012

Rights

© 2012 Daniel Crear

Document Type

Thesis

Department

Marine Science

First Advisor

James Sulikowski

Second Advisor

William Driggers III

Third Advisor

Eric Hoff Mayer

Abstract

Global declines in shark populations have been observed, including several species indigenous to the northwest Atlantic Ocean and the Gulf of Mexico (GOM). Attributing to these declines is a lack of abundance and distribution data of early life stages, particularly within essential habitats such as nursery grounds. Previous research has defined the Mississippi Sound as a multispecies shark nursery, therefore determining how abundance and distribution patterns change will aid in verifying where these species are throughout the year within this shark nursery. Thus, the objectives of the current study were to describe the variability in distributions of four shark species in the Mississippi Sound. From March 2009 to October 2011, 1,309 sharks including, 737 Atlantic sharpnose, Rhizoprionodon terraenovae, 332 finetooth, Carcharhinus isodon, 151 blacktip, Carcharhinus limbatus, and 89 bonnethead, Sphyrna tiburo, sharks were collected within the Mississippi Sound. Male Atlantic sharpnose were present in the sound throughout all life stages where as females left the sound once maturity was reached. Immature finetooth and blacktip utilized the Mississippi Sound as a nursery and left before maturity was reached. Low abundances of bonnethead suggested that this area is not as important for this species. All species preferred the Central and East Areas within the Mississippi Sound in 2010 and 2011, demonstrating the possible effect of environmental parameters such as temperature, salinity, and dissolved oxygen on shark distribution. Relatively higher abundances were observed in the summer compared to spring and fall for all species of sharks. This study confirms that the Mississippi Sound is an important nursery ground for Atlantic sharpnose, finetooth, and blacktip sharks.

Comments

Honors thesis

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