The mink is not a reliable sentinel species.
In a recent review paper, Basu et al. [Basu, N., Scheuhammer, A.M., Bursian, S.J., Elliott, J., Rouvinen-Watt, K., Chan, H.M., 2007. Mink as a sentinel species in environmental health. Environ. Res. 103, 130-144] suggested that the American mink (formerly Mustela vison, now Neovison vison) should be used as a sentinel species for studies of the effects of pollution on environmental health. They based this assertion in large part on their conclusion that mink meet a set of criteria required by a sentinel species. In this commentary, we suggest that Basu et al. overlooked an important criterion for sentinel species - that the species must be a continuous resident of the environment under evaluation. Across their native range and beyond, mink are commonly farmed for the fur industry, and a long history of studies has shown that where they are farmed, they escape. For example, in southern Ontario, Canada, 64% of the mink have been genetically identified as domestic in origin, or domestic-wild hybrids. Thus, we argue that mink do not meet the criterion of continuous residence, and cannot be reliably used as sentinel species. There is a strong likelihood of biased inference when mink are used for such purposes.