In a large skillet melt 2 tablespoons butter on medium-high. Season flesh side of fish with 1 teaspoon OLD BAY. Place fish skin-side up in skillet. Cook 5 minutes turning fish after 3 minutes. Remove fish from skillet. Keep warm. Reduce heat to medium.
Stir wine into skillet scraping bottom to loosen browned bits. Add remaining 1 tablespoon butter and green onion. Cook and stir 1 minute. Gradually stir in cream.
Stir in mustard and remaining 1/2 teaspoon OLD BAY. Simmer 2 minutes or until slightly thickened. Stir in crabmeat. Return fish to skillet. Cover. Cook 3 minutes longer or until fish flakes easily with a fork.