The output of hairy crabs from Suzhou's Yangcheng Lake would increase by at least 10 per cent this year because of cleaner water and warmer conditions, the authorities said yesterday as farmers began the harvest. Next year's harvest, however, would drop from the 2,200 tonnes expected this year to less than 1,000 tonnes as a result of the government's decision to slash the size of the netted crab-breeding area, according to Jiang Jinlong , vice-director of the Suzhou Agriculture and Forestry Bureau. The area is to be cut from 50 sq km to about 20 sq km by May. Yang Weilong , director of the Suzhou Yangcheng Lake Hairy Crab Association, said about 60 tonnes of the lake's hairy crabs would reach Hong Kong this season, with the first batch arriving on Tuesday. The average weight of male crabs was 210 grams and female crabs 155 grams, about 19 per cent and 8 per cent heavier than last season, farmers said. 'This year's hairy crabs are larger and heavier,' Mr Yang said. 'There are three reasons. The water is cleaner and has much less pollutants than last year. 'Farmers are raising crabs in a biological way - by restricting the number of juveniles, putting in a selected amount of feed and growing more waterweeds. And the weather is good, with a higher average temperature and more rain.' Farmer Yin Guishi said he had spent about 20 per cent more raising crabs this year but he believed his income would increase. Authorities have accused crab farmers of polluting the lake by introducing too much feed to boost yields, so they have decided to gradually phase out netted crab breeding, although harvesting of wild crabs will continue. The government announced in July that all netted breeding areas would be banned within the next couple of years to protect the lake, the backup water supply for Suzhou's more than 10 million residents after Tai Lake. Mr Jiang said about 1,500 households engaged in crab breeding - about half the current number - would lose their licences by the end of next year. 'The Suzhou government decided to cut down the netted crab-raising area dramatically in an effort to benefit the environment after the recent outbreak of blue-green algae in Tai Lake near Wuxi ,' he said. Crab farming hit a peak in 2000, with more than three-quarters of Yangcheng Lake netted by farmers. More than 300 tonnes of hairy crabs from the lake are destined for Beijing this year, while 515 tonnes will go to Shanghai, and 250 tonnes will go to Guangdong and Fujian .