Lake Michigan Mussels: Biologists are concerned as quaggas outmuscle zebras

Sure, zebra mussels have been great for Great Lake smallmouth fisheries, but the nonnative species has invaded with a potpourri of deleterious effects, too. Therefore, it should be good news that Lake Michigan's zebras are all but gone—except that they're being replaced by the quagga mussel, which does the same thing on a larger scale, including in deep, cold places where zebras can't survive.