Defense Date

8-11-2022

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David Kerstetter, Ph.D.

Second Advisor

Amy Hirons, Ph.D.

Third Advisor

Douglas Adams, M.S.

Abstract

State and federal agencies have issued consumption advisories for various fish species for many years, including in Florida. Upper-level predatory fish, such as tunas and mackerels, are especially popular with anglers but are susceptible to high levels of mercury through bioaccumulation and biomagnification. This study used two data sets over two time periods, 2010-2012 and 2020-2021, to compare mercury and trophic level relationships in nine coastal pelagic fishes is Southeastern Florida. As these species are popular in recreational fisheries, charter and tournament catches formed the base of the samples that were analyzed for total mercury along with carbon and nitrogen stable isotope ratios. Total mercury values were not significantly different between the two data sets for species that were directly comparable. Fork length and mercury were positively correlated for Blackfin Tuna, Dolphinfish, King Mackerel, Little Tunny, Skipjack Tuna, and Wahoo, all of which had more than 5 samples per species. Fork length and trophic level were positively correlated in all the aforementioned species except Skipjack Tuna. Trophic level and mercury were positively correlated in all the aforementioned species except King Mackerel. The results of this study indicated mercury levels remained stable between the two time periods and further support that mercury and trophic level are positively correlated. This study not only provides valuable data on understudied small-bodied tunas, but it is also replicable to build a robust temporal analysis on bioaccumulation in these species.

Available for download on Wednesday, September 13, 2023

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