HCNSO Student Theses and Dissertations

Defense Date


Document Type


Degree Name

M.S. Marine Biology

First Advisor

David Kerstetter, Ph.D.

Second Advisor

Christopher Blanar, Ph.D.

Third Advisor

Amy Hirons, Ph.D.


Community structure of Sargassum-associated organisms was examined from 11 sampling locations in the Florida Straits and Gulf Stream from May—September 2018 using a combination of modified shrimp trawls and dip nets. A total of 5413 organisms were collected from Sargassumhabitat representing 14 species from 10 families. A core group of organisms (Platynereis dumerilii, Litiopa melanostoma, Portunus sayi, Portunus spinimanus, Leander tenuicornis, and Latreutes fucorum) were found throughout the entirety of the geographic range surveyed. This core community was not found to vary significantly with increasing distance to shore (P=0.217) and latitude (P=0.217), nor did it correlate with environmental variables such as salinity (P=0.067), and temperature (P=0.193). However, community structure was found to vary with clump size (P=0.024), with larger clumps harboring more speciose communities. The Sargassumcommunity in the Florida Straits and Gulf Stream appears to provide habitat for a consistent core group of organisms. In turn, this stable group offers a sustainable food source for a variety of important, higher trophic level organisms that utilize Sargassumpatches for a food source, shelter, and breeding purposes.