How to Make It
Preheat the oven to 350°. In a large bowl, mix the 6 pounds of kosher salt with the chopped parsley, cilantro and rosemary. Add the egg whites and stir until the salt is evenly moistened.
Season the sea bass cavities with salt and fill them with the herb sprigs and the sliced lemon, orange and fennel.
Using half of the herbed salt mixture, form 2 mounds on each of 2 large rimmed baking sheets. Pat each mound into a rectangular bed about 1/2 inch thick and the length and width of the fish. Set each fish on a salt bed and cover with the remaining herbed salt, patting to enclose the fish completely.
Bake the fish in the oven for about 45 minutes, or until an instant-read thermometer inserted in the thickest part of the fish behind the head registers 135°.
Using a wooden spoon, tap the salt to crack it; lift off the crusts in large pieces. Carefully remove the fish skin and lift the fillets from the bones. Transfer to a platter and serve with lemon wedges.