Preheat your oven to 200°C (390°F) and select an ovenproof skillet or shallow roasting pan.
Zest the lemon and orange using a fine grater, then juice the lemon and set both zest and juice aside.
Chop the fresh parsley and mince the garlic, creating a fragrant herb mixture.
In a small bowl, whisk together the citrus zest, juice, chopped parsley, minced garlic, and olive oil to create a bright marinade.
Place the fish fillets, shrimp, and scallops into the prepared pan, arranging them so they are evenly spaced.
Use a basting brush or spoon to coat the seafood generously with the citrus-herb marinade.
Sprinkle the seafood evenly with flaky sea salt for enhanced flavor.
Transfer the pan to the oven and bake for 12-15 minutes, until the fish flakes easily, shrimp turns opaque, and scallops develop a golden edge.
Remove the pan from the oven and let the seafood rest for 5 minutes, allowing the flavors to settle and the textures to firm up slightly.
Serve the seafood hot, garnished with extra parsley if desired, alongside crusty bread or a fresh green salad.
