Authorities are fighting pollution in East China's Taihu Lake, partly caused by increased aquaculture, according to the Shanghai-based Jiefang Daily.
While industrial waste and domestic sewage are the main sources of pollution in the lake, the pollution brought about by increased and inappropriate aquaculture accounts for 7 percent of it.
Only 30 percent of the feed put into the lake is eaten by the fish. The rest, after subsiding to the bottom, ferments and produces organic substances such as nitrogen and phosphorus.
And in the 30 percent of feed eaten by fish, 91 percent of the resultant nitrogen and phosphorous are excreted back into the water.
This leads to an abnormal growth of blue-green algae.
The proliferation of waterweeds, together with the shallow depths, reduces the lake's ability to self-clean and makes the situation more serious, said Chen Hesheng, an official from the Taihu Lake Basin Authority under the Ministry of Water Resources.
The Taihu Lake is situated in Jiangsu and Zhejiang provinces, two of China's richest provinces.
(China Daily 12/11/2000)
