How big are the hooks you're using, wookie? Make sure they're big enough, especially if you're using big minnows.
I also use heavier line than most people (10 lb flouro) on our rattle reels so I can set the hook with a bit of gusto without worrying about breaking off. I might get a few less bites than my friends using 4 lb or 6 lb test, but in the long run I bet we both get the same number of fish on the ice.
I have read that mercury levels are a reason there is no commercial harvest on vermilion. But it was probably the same thing you read as I have not found a second source of that. There is commercial harvest of rustys on other Minnesota lakes so there must be a reason it's not done here.
For or what it's worth, the DNR has suggestions on how much fish to eat because of mercury.