Thaw fish, if frozen. Rinse fish; pat dry. Place fish in a shallow nonmetallic dish. For marinade, in a small bowl combine thawed apple juice concentrate, rosemary, pepper, and salt. Set aside 1/4 cup of the marinade. Pour remaining marinade over fish; turn fish to coat. Cover and marinate in the refrigerator for at least 1 hour or up to 2 hours.
At least 1 hour before smoke cooking, soak wood chunks in enough water to cover. Drain before using.
Drain fish, discarding marinade. In a smoker arrange preheated coals, drained wood chunks, and water pan according to manufacturers directions. Pour water into pan. Place fish on grill rack over water pan. Cover and smoke for 1-1/4 to 1-1/2 hours or just until fish flakes easily with a fork, brushing with the reserved 1/4 cup marinade after 1 hour smoke cooking.
Just before serving, drizzle fish with melted apple jelly. If desired, serve with steamed greens. Makes 4 servings.