Barplots illustrating results of sensitivity analysis used to identify the Hg sources that are most influential on Hg concentrations in freshwater and fish. The mutual information measure of sensitivity is plotted on the x axis, and the eight different model study regions on the y axis. The plots are separated by the six Hg effect variables: the THg concentrations in freshwater and the tissue Hg concentrations in the five fish species. The colored bars represent the eight Hg sources across the Great Bear Subbasin (GBS) and Great Slave Lake (GSL) models. Variables with negligible mutual information values are not adequately described by any of the Hg pathways considered in the model frameworks.