In the Battle of Savo Island one Australian and three American cruisers were sunk and one American cruiser and two destroyers were damaged. The Japanese had moderate damage to one cruiser. Mikawa, who was unaware Fletcher was preparing to pull back with the U.S. carriers, immediately went back to Rabaul without attempting to attack the transports. Mikawa was concerned about daylight U.S. carrier air attacks if he remained in the area. Without carrier air cover, Turner decided to pull back his remaining naval forces by the evening of 9 August. This left the Marines ashore without much of the heavy equipment, supplies and troops still aboard the transports. Mikawa's decision not to attempt to destroy the Allied transport ships was a big mistake.