Preheat the oven to 400 degrees. Season the fillets with salt and pepper and arrange them on a baking pan. Pour the wine over and dot with the butter.
Bake, uncovered, until the fish is just opaque through the thickest part, 6 to 10 minutes, depending on thickness of the fish. Transfer the fillets to warmplates and cover with foil.
Pour the pan juices into a saucepan and boil, stirring occasionally, until the liquid is reduced to about 2 tablespoons. Add the shrimp and parsley to the sauce and simmer until hot, about 1 minute longer. Taste the sauce for seasoning and spoon it over the fish.