Waste removal from raceways for raising aquatic animals is improved by providing a waste removal section at the downstream end of the raceways whereby the waste removal section is separated from the rest of the raceway by a vertical or near vertical screen. The mesh size of the screen is sufficient for the waste to pass through but not allow the aquatic animals to pass through. The natural flow of water through the raceway carries the waste material downstream within the raceway. A perforated pipe in the bottom of the waste removal section provides the outlet for the waste removal. A waste control valve connected to the perforated pipe controls the flow of the waste out of the waste removal section. Optional freeze protection for the waste control valve is provided.