As night fell on the first day, the Japanese defenders kept up sporadic harassing fire, but did not launch an attack on the Marines clinging to their beachhead and the territory won in the day's hard fighting. With Rear Admiral Shibazaki killed and their communication lines torn up, each Japanese unit had been acting in isolation since the start of the naval bombardment. The Marines brought a battery of 75 mm Pack Howitzers ashore, unpacked them and set them up for action for the next day's fight, but most of the second wave was unable to land. They spent the night floating in the lagoon without food or water, trying to sleep in their Higgins boats. During the night, some Japanese marines swam to some of the wrecked LVTs in the lagoon, and to the "Saida Maru" (斉田丸), a wrecked Japanese steamship lying west of the main pier. They waited for dawn, when they intended to fire on U.S. forces from behind. Lacking central direction, the Japanese were unable to coordinate for a counterattack against the toehold the Marines held on the island. The feared counterattack never came, and the Marines held their ground. By the end of the first day, of the 5,000 Marines put ashore, 1,500 were casualties, either dead or wounded.