It has a surface area of 3,585 km² and a volume of 25 km³. Its average depth is 8 meters. The lake provides habitat for a half million migratory birds, and is a favorite destination for birding. It is fed by the Gan and Xiu rivers, which connect to the Yangtse through a channel.
During the winter, the lake becomes the home of large numbers of migrating Siberian cranes, up to 90% of which winter over there.
There has been a fishing ban in place since 2002.
Calls have been made for action to be taken to save the porpoise, of which there are about 1,400 left living, with between 700 and 900 in the Yangtze, with about another 500 in Poyang and Dongting Lakes.
2007 population levels are less than half the 1997 levels, and the population is dropping at a rate of 7.3 per cent per year.
Sand dredging has become a mainstay of local economic development in the last few years, and is an important source of revenue in the region that borders Poyang Lake. But at the same time, high-density dredging projects have been the principal cause of the death of the local wildlife population.
Dredging makes the waters of the lake muddier, and the porpoises cannot see as far as they once could, and have to rely on their highly-developed sonar systems to avoid obstacles and look for food. Large ships enter and leave the lake at the rate of two a minute and such a high density of shipping means the porpoises have difficulty hearing their food, and also cannot swim freely from one bank to the other.