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Diet influences on growth and mercury concentrations of two salmonid species from lakes in the eastern Canadian Arctic.

https://arctichealth.org/en/permalink/ahliterature304422
Source
Environ Pollut. 2021 Jan 01; 268(Pt B):115820
Publication Type
Journal Article
Date
Jan-01-2021
Author
John Chételat
Yueting Shao
Murray C Richardson
Gwyneth A MacMillan
Marc Amyot
Paul E Drevnick
Hardeep Gill
Günter Köck
Derek C G Muir
Author Affiliation
Environment and Climate Change Canada, National Wildlife Research Centre, Ottawa, ON, K1A 0H3, Canada. Electronic address: john.chetelat@canada.ca.
Source
Environ Pollut. 2021 Jan 01; 268(Pt B):115820
Date
Jan-01-2021
Language
English
Publication Type
Journal Article
Keywords
Animals
Arctic Regions
Canada
Diet
Environmental monitoring
Lakes
Mercury - analysis
Salmonidae
Water Pollutants, Chemical - analysis
Abstract
Diet, age, and growth rate influences on fish mercury concentrations were investigated for Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in lakes of the eastern Canadian Arctic. We hypothesized that faster-growing fish have lower mercury concentrations because of growth dilution, a process whereby more efficient growth dilutes a fish's mercury burden. Using datasets of 57 brook trout and 133 Arctic char, linear regression modelling showed fish age and diet indices were the dominant explanatory variables of muscle mercury concentrations for both species. Faster-growing fish (based on length-at-age) fed at a higher trophic position, and as a result, their mercury concentrations were not lower than slower-growing fish. Muscle RNA/DNA ratios were used as a physiological indicator of short-term growth rate (days to weeks). Slower growth of Arctic char, inferred from RNA/DNA ratios, was found in winter versus summer and in polar desert versus tundra lakes, but RNA/DNA ratio was (at best) a weak predictor of fish mercury concentration. Net effects of diet and age on mercury concentration were greater than any potential offset by biomass dilution in faster-growing fish. In these resource-poor Arctic lakes, faster growth was associated with feeding at a higher trophic position, likely due to greater caloric (and mercury) intake, rather than growth efficiency.
PubMed ID
33120140 View in PubMed
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