BEIJING, CHINA—The government of China has asserted its ownership of shipwrecks in an area covering most of the South China Sea, which it claims as its territorial waters. “We want to find more evidence that can prove Chinese people went there and lived there, historical evidence that can help prove China is the sovereign owner of the South China Sea,” said Liu Shuguang, head of the government’s Center of Underwater Cultural Heritage. Chinese archaeologists are planning a comprehensive underwater survey of areas of the South China Sea that are in dispute with Vietnam, Malaysia, Brunei, Taiwan, and the Philippines. But UNESCO encourages countries to share the excavation of underwater cultural heritage sites, since a ship and its owner, cargo, and crew may have been assembled from international sources in antiquity. “If you look around the world now, the majority of projects are multinational ones,” said Ulrike Guerin of UNESCO.