JENA, GERMANY—An international team of researchers led by Mark Hudson of the Max Planck Institute for the Science of Human History suggests that fish may have been raised for food in China as early as 6200 B.C. The scientists analyzed and compared carp teeth unearthed at Jiahu, a Neolithic site in central China, with remains of fish unearthed at other archaeological sites, and fish raised in modern fish farms in Japan. In earlier periods at Jiahu, when fish were caught in the wild during the spawning season, the catch consisted of adult fish, the researchers explained, but beginning around 6200 B.C., both mature and immature fish were processed at the site. Hudson and his colleagues think the early farmers began to keep some of the wild-caught carp alive in confined spaces, such as rice paddy fields, where they continued to spawn. When the water was drained, both the mature and immature fish were harvested. The high proportion of bones at Jiahu from a type of carp found less commonly in the wild is also evidence for the practice of aquaculture, the researchers added, indicating that the fish farmers kept their preferred variety. To read about large-scale construction at a Neolithic city in the Yangtze Delta, go to "Early Signs of Empire."