For stuffing, in a medium saucepan cook celery and onion in margarine or butter until onion is tender but not brown; remove from heat. Stir in chicken broth, apple cider or apple juice, coriander, allspice, and pepper.
In a medium bowl combine stuffing mix, chopped pear, couscous, raisins, and parsley. Add celery mixture; toss lightly to mix.
Rinse fish; pat dry with paper towels. Fill fish cavity with 1 cup of the stuffing. Tie or skewer fish closed. Place stuffed fish on a greased rack in a large shallow baking pan. Place the remaining stuffing in a 1-quart casserole; cover casserole.
Brush outside of fish with oil; cover loosely with foil. Bake fish and stuffing in a 350 degree F oven about 50 minutes for a salmon roast (50 to 60 minutes for a whole dressed salmon) or until fish flakes easily with a fork and stuffing is heated through. Garnish with pear wedges and celery leaves, if desired. Makes 8 servings.