From Great Lakes Wiki
Blueback herring are saltwater fish that can live in freshwater. They are flat sided fish with round bellies having dark blue or bronz backs with a forked tail. There are a favorite food of bass and can grow to be a maximum size of 16 inches. The problem with Blueback herring is that they eat fish eggs and food the other fish eat, so they can outcompete large mouth species rather quickly. {If your eating someones food and their children at the same time, it is unlikely for your family to survive} It is illegal to use these fish as bait where they don't already exist, so don't even think about it!
Image from: njfieldoffice.fws.gov/Coastal%20Award/Fish.htm
