Preheat the oven to 400°F. Line a baking sheet with parchment paper or lightly grease it. Cut each 12-ounce Emperor fish fillet crosswise into two roughly equal pieces, creating 4 portions.

Pat the fish dry with paper towels. Arrange the portions on the prepared baking sheet. Brush each piece lightly with olive oil and season with salt and black pepper.

Place the Deep Sea Crab Meat in a large bowl. Gently add the mayonnaise, 2 tablespoons lemon juice, lemon zest, chives, 2 tablespoons parsley, garlic, Old Bay seasoning, and cayenne. Mix just until combined, being careful not to break up the crab too much.

Divide approximately 3 to 3½ ounces of the crab mixture over each fish portion, gently mounding it on top. Sprinkle the Parmesan evenly over the crab.

Bake for 12 to 15 minutes, or until the fish is opaque and flakes easily with a fork and the crab topping is heated through. For a lightly golden topping, broil for 30 to 60 seconds at the end, watching carefully.

While the fish cooks, melt the butter in a small saucepan over low heat. Remove from the heat and stir in the remaining 2 tablespoons lemon juice and 2 teaspoons parsley.

Transfer the crab-topped Emperor fish to serving plates. Spoon the lemon butter around each portion rather than directly over the crab topping. Garnish with fresh chives or parsley and serve with lemon wedges.