High mercury levels in Antarctic toothfish Dissostichus mawsoni from the Southwest Pacific sector of the Southern Ocean

Queirós, José P.; Hill, Simeon L. ORCID: https://orcid.org/0000-0003-1441-8769; Pinkerton, Matt; Vacchi, Marino; Coelho, João P.; Pereira, Eduarda; Ramos, Jaime A.; Seco, José; Stevens, Darren W.; Xavier, José C. ORCID: https://orcid.org/0000-0002-9621-6660. 2020 High mercury levels in Antarctic toothfish Dissostichus mawsoni from the Southwest Pacific sector of the Southern Ocean. Environmental Research, 187, 109680. https://doi.org/10.1016/j.envres.2020.109680

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Text © 2020 published by Elsevier. This manuscript is made available under the Elsevier user license https://www.elsevier.com/open-access/userlicense/1.0 1-s2.0-S0013935120305739-am.pdf - Accepted Version Available under License Creative Commons Attribution Non-commercial No Derivatives 4.0. Download (515kB) | Preview

Abstract/Summary

Mercury is a bioaccumulating toxic pollutant which can reach humans through the consumption of contaminated food (e.g. marine fish). Although the Southern Ocean is often portrayed as a pristine ecosystem, its fishery products are not immune to mercury contamination. We analysed mercury concentration (organic and inorganic forms – T-Hg) in the muscle of Antarctic toothfish, Dissostichus mawsoni, a long-lived top predator which supports a highly profitable fishery. Our samples were collected in three fishing areas (one seamount and two on the continental slope) in the Southwest Pacific Sector of the Southern Ocean during the 2016/2017 fishing season. Mercury levels and the size range of fish varied between fishing areas, with the highest levels (0.68 ± 0.45 mg kg−1 wwt) occurring on the Amundsen Sea seamount where catches were dominated by larger, older fish. The most parsimonious model of mercury concentration included both age and habitat (seamount vs continental slope) as explanatory variables. Mean mercury levels for each fishing area were higher than those in all previous studies of D. mawsoni, with mean values for the Amundsen Sea seamount exceeding the 0.5 mg kg−1 food safety threshold for the first time. It might therefore be appropriate to add D. mawsoni to the list of taxa, such as swordfish and sharks, which are known to exceed this threshold. This apparent increase in mercury levels suggests a recent contamination event which affected the Southwest Pacific sector, including both the Amundsen and Dumont D'Urville seas.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.envres.2020.109680
ISSN:	00139351
Additional Keywords:	Fisheries, Contaminants, Antarctic resources, Trace elements
Date made live:	01 Jun 2020 10:47 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/527842

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