Thaw fish, if frozen. Preheat broiler. Place the bread crumbs in a shallow baking pan. Broil 4 inches from heat for 1 to 2 minutes or until lightly toasted, stirring once. Set bread crumbs aside.
Measure thickness of fish. Place fish on the greased unheated rack of broiler pan, tucking under any thin edges. Broil 4 inches from heat for 4 to 6 minutes per 1/2-inch thickness or until fish just begins to flake easily with a fork. Turn over 1-inch-thick fillets halfway through broiling.
Meanwhile, in a small bowl stir together mayonnaise and pesto; set aside. Combine toasted bread crumbs and cheese. Spoon mayonnaise mixture over fillets. Sprinkle with crumb mixture. Broil 1 to 2 minutes more or until crumbs are lightly browned. Makes 4 servings.