Believe it or not, archeologists have located the sites of 2,000 ships that sank in China's territorial waters during the heyday of its marine trade.

China was a major maritime power between the 10th and 16th centuries, and the great exploits of Zheng He give an idea of Ming Dynasty's (1368-1644) might on the sea.

The 2,000 wreckages won't be the last to be found, because State Administration of Cultural Heritage (SACH) Director Shan Jixiang says many more are waiting to be located.

Archeologists and other experts are now trying to find the sunken treasures in the Grand Canal, and their number can be "big", Shan says.

Work on the 1,700-km-long canal linking Beijing with Hangzhou began in the 5th century BC. So deft were the engineers of the times, and so farsighted was their vision that the canal is in use even today.

The discovery of the Song Dynasty (960-1279) ship Nanhai-I, which was finally hauled from South China Sea on Saturday, prompted the government to draft a plan to protect its relics lying under water, Shan says. In fact, the work on the plan has already begun.

The discoveries have created the need for regulations and actions, too. "Now that everyone has realized the value of the cultural relics lying under water, it has become all the more urgent to keep thieves and smugglers away from them."

If the country wants to better protect these priceless objects, it has to join the UN Educational, Scientific and Cultural Organization (UNESCO) Convention on the Protection of Underwater Cultural Heritage, says Zhang Wei, director of National Museum of China's underwater archaeological center.

China has just two instruments to protect its underwater heritage: the Cultural Heritage Protection Law, promulgated in 1981 and amended in 2003, and the Regulation on the Protection of Underwater Heritage, announced by the State Council in 1989.

Most of the relics looted from the seas and rivers often make their way abroad, and smugglers have been particularly rampant over the last two years, Shan says.

Art collectors and dealers across the world have become especially interested in China's underwater heritage since 2005, when about 15,000 relics, mainly 300-year-old blue-and-white porcelain, were found on a 13.5-m sunken ship off the coast of Fujian Province. (By Wang Shanshan)