Studies that assess mercury bioaccumulation in small carnivores in terrestrial habitats are limited. We quantified total mercury (THg) in American marten (Martes americana) that were harvested for fur in Michigan, US, during 2013 and 2014. We quantified THg (dry weight) in hair, kidney, and liver samples and further analyzed hair for potential demographic and ecological factors that influence THg bioaccumulation. We found THg concentrations to be the highest in hair (1.228±0.475 lg/g, n=40), followed by kidney (0.922±0.651 lg/g, n=29) and liver (0.344±0.219 lg/g, n=26). Total mercury distributed predictably and significantly between tissue types, and hair was moderately predictive at modeling THg in kidney (R2=0.50, P<0.001, n=29) and weakly predictive in liver (R2=0.35, P<0.001, n=26), suggesting that hair, which is easily obtained, could be a useful sample type for future biomonitoring programs. The concentrations of THg in hair were higher in adults relative to juveniles, and adult female martens had the highest levels of THg (1.980±0.188 lg/g), as compared to juveniles and adult males. Results of generalized linear modeling suggested that THg hair concentrations were positively associated with marten age and trophic position (stable isotope ratio, δ15N). An interaction between δ15N and the year marten carcasses were collected showed that δ15N alone could be highly predictive of THg in some years but not in others. Annual changes in diet could lead to differing rates of mercury bioaccumulation and alter the usefulness of δ15N to predict THg in marten tissues. Further research should explore the connections between changes in prey availability, types of prey consumed, and the influence on bioaccumulation rates of mercury in terrestrial system mesocarnivores.
Bibliographical noteFunding Information:
We are grateful to the Sault Tribe of Chippewa Indians; the Little River Band of Ottawa Indians; and all registered fur trappers in Michigan for support in sample collection. We thank the following for their support at various stages throughout this project: Eric Clark, Brad Silet, Debra Miller, Phil Myers, Susan Hoffman, Samantha Jackson, Robert Sanders, and Paul Keenlance. We thank the following for their funding support and in-kind donations: University of Michigan Biological Station; University of Michigan–Flint Summer Undergraduate Re- search Experience; UM–Flint Biology Department, Evansville Zoological Society, Ulysses S. Seal Conservation Grant through the Minnesota Zoo; and the PPG Sustainability & Conservation Fund through the Pittsburgh Zoo & PPG Aquarium. This is a SeaWorld Parks and Entertainment technical contribution 2019-14.
© Wildlife Disease Association 2020.
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- Martes americana
- Stable isotopes
- Upper Great Lakes region