Metal concentrations in coastal sharks from The Bahamas with a focus on the Caribbean Reef shark

Oliver N Shipley,Cheng-Shiuan Lee,Nicholas S Fisher,James K Sternlicht,Sami Kattan,Erica R Staaterman,Neil Hammerschlag,Austin J Gallagher

doi:10.1038/s41598-020-79973-w

Oliver N Shipley, Cheng-Shiuan Lee + Show 6 more

Open Access

https://doi.org/10.1038/s41598-020-79973-w

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Journal: Scientific Reports	Publication Date: Jan 8, 2021
Citations: 14	License type: open-access

Affiliation: Stony Brook University, University of Miami

Abstract

Over the last century anthropogenic activities have rapidly increased the influx of metals and metalloids entering the marine environment, which can bioaccumulate and biomagnify in marine top consumers. This may elicit sublethal effects on target organisms, having broad implications for human seafood consumers. We provide the first assessment of metal (Cd, Pb, Cr, Mn, Co, Cu, Zn, As, Ag, and THg) and metalloid (As) concentrations in the muscle tissue of coastal sharks from The Bahamas. A total of 36 individual sharks from six species were evaluated, spanning two regions/study areas, with a focus on the Caribbean reef shark (Carcharhinus perezi), and to a lesser extent the tiger shark (Galeocerdo cuvier). This is due their high relative abundance and ecological significance throughout coastal Bahamian and regional ecosystems. Caribbean reef sharks exhibited some of the highest metal concentrations compared to five other species, and peaks in the concentrations of Pb, Cr, Cu were observed as individuals reached sexual maturity. Observations were attributed to foraging on larger, more piscivorous prey, high longevity, as well a potential slowing rate of growth. We observed correlations between some metals, which are challenging to interpret but may be attributed to trophic level and ambient metal conditions. Our results provide the first account of metal concentrations in Bahamian sharks, suggesting individuals exhibit high concentrations which may potentially cause sublethal effects. Finally, these findings underscore the potential toxicity of shark meat and have significant implications for human consumers.

Highlights

Over the last century anthropogenic activities have rapidly increased the influx of metals and metalloids entering the marine environment, which can bioaccumulate and biomagnify in marine top consumers
The highest concentrations of Cd were found in the tissues of Nurse sharks (0.263 ± 0.301 mg kg−1) and Lemon sharks (0.231 ± 0.170 mg kg−1) and the lowest values were found in Caribbean reef sharks (0.119 ± 0.085 mg kg−1)
The study provides the first analysis of metal concentrations in the tissues of coastal sharks from The Bahamas

Summary

Introduction

Over the last century anthropogenic activities have rapidly increased the influx of metals and metalloids entering the marine environment, which can bioaccumulate and biomagnify in marine top consumers. A need to establish baseline concentrations of metals in sharks and their relatives, as well as potential routes of exposure is r equired[14,17,20] This is true for developing nations, where less stringent environmental regulations regarding wastewater treatment, anthropogenic emissions, and subsequent management may lead to elevated levels of metals entering coastal waters. The developing nation of The Bahamas houses a diversity of productive marine ecosystems such as seagrass beds, oolitic sand banks, open ocean, coral reefs, and m angroves[27] This high productivity supports biomass of upper trophic level predators, such as sharks, and large teleost fishes[28,29]. This will allow for the determination of potential hotspots that may benefit from focused environmental m anagement[16]

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