Mix garlic powder and crushed crackers together; set aside. Pat dry haddock loins and sprinkle both sides with salt and pepper. Spread 1 tablespoon melted butter onto a cookie sheet and place haddock on top. Pour remaining melted butter over haddock and sprinkle cracker crumb mixture over the top, pressing lightly. Bake in a 350-degree oven for 20 minutes, until the fish reaches an internal temperature of 145 degrees.