Preheat oven to 425F. Brush a 15 x 10 x 2 nch baking dish with olive oil. Rub fish inside and out with 1 tablespoon oil and sprinkle with salt and pepper. Sprinkle fish cavities with crushed fennel seeds. Arrange fish in prepared baking dish; drizzle with 1/2 cup Pernod. Cover tightly with foil. Bake until fish is almost cooked through, about 25 minutes. Meanwhile, heat remaining 2 tablespoons of oil in a heavy large skillet over medium heat. Add sliced fennel and saut?ntil tender, about 10 minutes. Season to taste with salt and pepper.
Sprinkle saut? fennel over fish. Bake uncovered until fish is opaque, about 5 minutes longer. Garnish fish with reserved fennel fronds. Serve hot with lemon wedges.