Marine & Environmental Sciences Faculty Articles

Bioaccumulation and Biomagnification of Mercury and Methylmercury in Four Sympatric Coastal Sharks in a Protected Subtropical Lagoon

ORCID

0000-0002-4440-8767

ResearcherID

I-5396-2012

Document Type

Article

Publication Title

Marine Pollution Bulletin

ISSN

0025-326X

Publication Date

3-15-2017

Keywords

Apex predators, Sharks, Florida Bay, Mercury, Stable isotopes, Trophic transfer

Abstract

Mercury bioaccumulation is frequently observed in marine ecosystems, often with stronger effects at higher trophic levels. We compared total mercury (THg) and methylmercury (MeHg) from muscle with length, comparative isotopic niche, and diet (via δ13C and δ15N) among four sympatric coastal sharks in Florida Bay (USA): blacknose, blacktip, bull, and lemon. Mercury in blacknose and blacktip sharks increased significantly with size, whereas bull and lemon sharks had a high variance in mercury relative to size. Both δ13C and δ15N were consistent with general resource use and trophic position relationships across all species. A significant relationship was observed between δ13C and mercury in blacktip sharks, suggesting an ontogenetic shift isotopic niche, possibly a dietary change. Multiple regression showed that δ13C and δ15N were the strongest factors regarding mercury bioaccumulation in individuals across all species. Additional research is recommended to resolve the mechanisms that determine mercury biomagnification in individual shark species.

DOI

10.1016/j.marpolbul.2017.01.033

Volume

116

Issue

1-2

First Page

357

Last Page

364

Comments

©2017 Elsevier Ltd. All rights reserved.

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