In a small bowl, mix the maple syrup, soy sauce, garlic, garlic salt and pepper.
Place salmon in a shallow glass baking dish and coat with the maple syrup mixture. Cover the dish and marinade salmon in the refrigerator 30 minutes, turning once.
Preheat oven to 400F (200C).
Place the baking dish in the preheated oven and bake salmon uncovered 20 minutes or until it easily flakes with a fork.