About 100,000 fishermen living around the Poyang, China's largest freshwater lake, docked their vessels at midday Saturday for a three-month annual fishing ban.

The seasonal ban, in place since 2002, is considered crucial to sustain the lake's ecology and fishing resources.

Though he will be left without a job until June 20, Deng Shenghua, a fisherman in the eastern Jiangxi Province, said he would cooperate as usual.

"I know it's important to ban fishing in the spring spawning season," he said. "When the ban ends in three months, fishing actually becomes easier."

During the ban, local authorities will patrol the water as well as local markets and restaurants to guard against illegal fishing, said Guang Shaofei, an official with the provincial fishery bureau.

Meanwhile, the government would also provide training for the laid-off fishermen and encourage them to take temporary jobs in other industries.

Poyang Lake, at the lower reaches of the Yangtze River, China's longest waterway, has suffered a decline in fish reproduction for two decades, a result of overfishing, pollution and depletion of sand in the lake area.

But nine consecutive years of the spring fishing ban has helped improve the lake ecology, said Guang. "Last year, the lake reported a 7.3-percent year-on-year rise in fish output."

Poyang Lake, covering 3,583 square km, is home to at least 140 fish varieties.