The warnings will target women of child-bearing age. It's been known since at least 1994, that the lake trout have relatively high levels of a mercury compound.
Mercury can cause severe birth defects in unborn children.
Jack Stanford, the director of the University of Montana's biological research station at Yellow Bay on Flathead Lake, says the mercury is likely a result of global industrial pollution. Officials with the State Department of Health and Human Services don't believe anyone's been adversely affected by consuming fish in Montana because of mercury.