Cormorant
After hundreds of studies, it has been difficult to link fish predation by cormorants (Phalacrocorax auritus) to the reduction of fishing quality in Minnesota lakes. It appears that game fish such as walleye and northern pike make up from less than 1% to nearly 3% of the bird's diet. They eat only small fish. Many of the fish they eat are perch, which prey on walleye, and it is even possible that by culling small walleye or northerns, they increase the growth rate for those fish in two way. One is by reducing competition between fish for food, and the other is by exerting selective pressure…