The Michigan DNR department has been issuing, for years now, advisories to fishermen about consuming fish from the surrounding lakes, according to which, many species contain high levels of Mercury and PCBs. Among them is also Walleye, and from the charts, the older/larger the fish, the more polluted it is.

On the other side, it has been a few months that I keep seeing expensive huge walleye fillets for sale at Whole Foods. The tags next to the fillets say: "Wild-caught in US lakes (I imagine Michigan) with gill nets".

Does anybody know if these fish are really polluted or not?