Chinese fishermen are setting their eyes on the vast and largely untapped fishery resources in the South China Sea with the sail of a big fishing fleet to the region.

Fishermen working in the South China Sea. [File photo]

The fleet of 30 boats, including a 3,000-tonne lead boat carrying fresh water, fuel, and other supply, arrived at Zhubi shoal for fishing on Wednesday, almost a week after it left port in southern Hainan province.

Fishermen of the island province have been fishing in the South China Sea for centuries but fishing in such a big fleet is a rarity.

Zhang Huazhong, head of the maritime and fishery bureau of Sanya city, said the big-fleet fishing is not a government-sponsored show. Instead, fishermen initiated it, and local fishing cooperatives organized the activity.

"We yearned for fishing in this region. But if we went alone, the risks of being caught in storms or harassed by foreign vessels were high," said Liang Yapai, head of one of the two fishing cooperatives behind the event. "Now, as we go together, we can sit down to discuss and find solutions to any problem we encounter."

Indeed, some fishermen complained that suspected Vietnamese fishing vessels were like "shadow" tailing the fleet along the way.

"There are too many of them," said a chief mate on the lead boat Qiongsanya F8168. "They shouldn't be fishing in China's waters. But for many times we just didn't know how to deal with them."

He said that one night he found a line of at least 40 Vietnamese fishing boats mooring on the sea. Lights shining from the boats was a spectacular scene to watch.

China claims sovereignty over an area of 820,000 square sea miles in the South China Sea, stretching from Qiongnan shoal in the north to Zenmu hidden shoal in the south, Hailima shoal in the east to Wan'an shoal in the west.