Chinese ancestors had since the late Han Dynasty (206 BC-220 AD) at the latest been engaged in fishing and other production activities in the South China Sea.
The book Yi Wu Zhi written by Yang Fu in the Eastern Han Dynasty (AD 25-220) contains a record saying that in the South China Sea there are "Daimao" (hawksbill sea turtles), "Jibi" (another species of sea turtle), "Luyu" (literally "deer fish"), "Jiaoyu" (Scomberomorus) and other species.
In Fu Nan Zhuan, a book written by Kang Tai from the State of Wu during the Three Kingdoms Period (AD 220-265), there is the record that "in Zhanghai, to the corals shoal, there is Pangaea at the bottom of the shoal, upon which the corals grow", indicating that the South China Sea is rich in coral resources.
It is recorded in Wu Lu written by Zhang Bo in the Jin Dynasty (AD 266-420) that, "Zhanghai of Jiaozhou Prefecture produces corals which are harvested with iron nets."
It is recorded in Tong Dian, a book written by Du You in the Tang Dynasty (AD 618-907) that, "Prior to the Xia, Shang and Zhou Dynasties, the region to the south of Wuling and the north of Zhanghai had been the desolate area.
In the Northern Song Dynasty (AD 960-1127), Zhang Shizheng wrote in Juan You Za Lu that "It is said in Miscellaneous Records of Lingnan that‘On the beach, there is a pond, from which the locals mined pearls for sale.'
In the Southern Song Dynasty (AD 1127-1279), Zhou Qufei recorded in Ling Wai Dai Da that, "The pearl-producing area in Hepu is known as Duanwangchi Pond.