Black Bass and Gamberi Cacciucco

Name: Black Bass and Gamberi Cacciucco
Ingredients: 1 cup milk; Pinch cayenne; 1 fresh bay leaf; 1 cup polenta; 1/4 cup mascarpone cheese; 1/4 cup grated Parmesan; Nonstick cooking spray, for spraying the baking dish; 1/2 bottle white wine; 1 head fennel with nice fronds, chopped; 1 onion, chopped; Red pepper flakes, as needed; Kosher salt; One 32-ounce can whole San Marzano tomatoes; 1 cup shrimp shells; 1 cod carcass; 8 ounces haricot verts; 2 tablespoons olive oil; 1 clove garlic, minced; 8 ounces littleneck clams; Pinch saffron; Pinch fennel pollen, plus more for garnish; 1/2 lemon, juiced; Four 4-ounce black bass fillets, skin on, patted dry; 8 ounces giant shrimp, shelled and deveined