The two views above are taken from the same vantage point less than 90 days apart. They show Yinshan Island in Poyang Lake, China’s largest freshwater lake, which has been undergoing repeated cycles of shrinkage. At the time of the bottom photo was taken, late July, the lake covered an area of 3,990 square kilometers. The upper photo was taken this week. The lake’s surface area had shrunk to 1,060 square kilometers. There are more photos taken this week of Poyang Lake here.
That, though, is not as small as the lake got at the beginning of this year when it was down to 188 square kilometers. In its pomp, Poyang covers 4,500 square kilometers, an area six times the size of Singapore.
The lake is fed by five rivers in Jiangxi and empties into the Yangtze. Its water level now regularly falls so far that fishing is possible for barely three months of the year. The lake used to provide a livelihood for a fleet of 10,00 fishing boats, as well as supporting hundreds of thousands of migratory birds including the Siberian crane in winter, that, like the fishermen, depend on a lake full of fish to survive.
Poyang is also home to a rare finless porpoise, which is increasingly threatened with extinction. Its numbers in Lakes Poyang and Dongting were down to 600 in 2006 in a count that also covered the Yangtse. The World Wide Fund for Nature (WWF) is due to conduct its next survey in November and December. The results are awaited with some trepidation. The Yangtse’s other rare porpoise, the Baiji, has become extinct.
Poyang has been in decline for a decade, a casualty of industrialization, urbanization and agriculture. The WWF estimates that half China’s industrial waste and sewage ends up in the Yangtse. Some of that feeds into the lake. Only now are efforts being made to regenerate it before it is too late.