Limited effects of changing prey fish communities on food quality for aquatic predators in the eastern Canadian Arctic in terms of essential fatty acids, methylmercury and selenium. (January 2019)

• Record Type: Journal Article
• Authors: Pedro, Sara; Fisk, Aaron T.; Ferguson, Steven H.; Hussey, Nigel E.; Kessel, Steven T.; McKinney, Melissa A.
• Is Part Of: Chemosphere. Volume 214(2019)
• Page Start: 855
• Page End: 865
• Publication Date: 2019-01
• Subjects: Species redistribution -- Fatty acids -- Nutritional value -- Prey fish -- Se:Hg ratios -- Species differences; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.09.167
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: We determined concentrations of eicosapentaenoic and docosahexaenoic acids (EPA + DHA), Σ omega -3, polyunsaturated fatty acids (ΣPUFA), selenium, methylmercury, and selenium:methylmercury (Se:Hg) ratios in native and northward-redistributing sub-Arctic marine fish and invertebrates from low, mid-, and high Canadian Arctic latitudes. There was no clear latitudinal trend in nutrient or contaminant concentrations. Among species, EPA + DHA concentrations in native Arctic cod ( Boreogadus saida ) were similar to concentrations in sub-Arctic capelin ( Mallotus villosus ) and sand lance ( Ammodytes spp.) (444–658 mg.100 g -1 ), and higher than in most other species. Concentrations of EPA + DHA were related to lipid content, but to a greater extent for higher trophic position species ( R 2 = 0.83) than for species at lower trophic positions ( R 2 = 0.61). Selenium concentrations were higher in sand lance (1.15 ± 0.16 μg g −1 ) than in all other species (0.30–0.69 μg g −1 ), which was significantly, but weakly, explained by more pelagic feeding in sand lance. Methylmercury concentrations were similar (and Se:Hg ratios were higher) in capelin, sand lance, and Arctic cod (0.01–0.03 μg g −1 wet weight (ww)) and lower than in other prey (0.12–0.26 μg g −1 ww), which was significantly explained by the smaller size of these species and more pelagic feeding habits than other fish. These results suggested that a shift in prey fish composition from Arctic cod to capelin and/or sand lance is unlikely to reduce the food quality of the prey available to marine predators at least with respect to concentrations of essential fatty acids, selenium, and Se:Hg ratios. Graphical abstract: Image 1 Highlights: Essential fatty acids, Se levels and Se:Hg ratios in Arctic vs boreal prey fish. Boreal capelin and sandlance had similar EPA + DHA, ω 3, and PUFA levels to Arctic cod. Higher Se levels in sand lance compared to other fish and invertebrates. Higher Se:Hg molar ratios in sand lance and capelin compared to Arctic cod. Overall similar nutritional quality in capelin and sand lance compared to cod.