HAIKOU - Some 8,000 fishing boats from South China's Hainan province returned to port on Monday as the 18th seasonal fishing moratorium began in the South China Sea.

From May 16 to August 1, no fishing is allowed in parts of the sea under China's jurisdiction except by single-layer gill nets or other approved methods, including conventional angling.

According to provincial fisheries department, the 7,952 fishing boats affected by the ban account for 32 percent of fishing boats in the province, with over 36,000 fishermen affected.

During the moratorium, these fishermen receive training on regulations, new technology and navigational safety.

Fishing bans in the South China Sea began in 1999. Although they have reduced the income of some fishermen, bans protect fisheries and ensure the industry's sustainability.

Annual fishing bans began in the Yangtze River and Poyang Lake, China's largest body of freshwater, in March.