Yul Kwon:
China's largest freshwater lake is drying up. At its peak, it covers an area larger than the state of Rhode Island. But now it's just a shadow of what it once was, endangering the world's only freshwater porpoise and the migratory birds that flock to its shores. According to state-owned broadcaster, CCTV, it's because of a prolonged drought that started last year.

Reporter:
China's largest freshwater lake no more. Poyang Lake once had a surface area of 3,500 square kilometers. And now this is all that's left.

Ge Gang, Professor of Wetlands Studies, Nanchang University:
When there's ample rainfall, the whole area's covered by water. Boats can sail through. But during such periods of drought, all this land emerges.

Reporter:
Once a favorite habitat for migratory birds, animals might now have to look elsewhere. Jiangxi province has endured a prolonged drought that started last year. In September, water levels in Lake Poyang had fallen to less than 12 meters, as the drought period started four months earlier than normal.

Pan Hanming, Jiangxi Water Bureau:
Since 2003, water levels at Poyang have been about one or two grades lower than previous years. This indicates that the drought situation is getting more severe.

Reporter:
Professor Ge has conducted research on Lake Poyang for many years. He sees every day how the drought has impacted the area.

Ge Gang, Professor of Wetlands Studies, Nanchang University:
It used to be that vegetation here is about 70 centimeters tall. Sometimes it can be as tall as a person. But because of the drought, water covers the land for only one month a year. It used to be at least three to four months.

Reporter:
While animals who depend on the land may feel the pinch when it comes to food, for local residents, it's lost business. According to the local bureau of fisheries and aquatic resources, the prolonged drought has reduced fish stocks by more than 60 percent.

Xiong Haibing, Local Resident:
I remember in the past, when there was a strong wind, the waves would carry fish on shore. All the villagers needed to do was pick them up.

Reporter:
Amid all the signs of distress at Lake Poyang, migratory birds seem to be the only stable factor. According to an investigation at the end of last year, migratory birds still numbered about 50,000. But whether they'll choose to stay as the drought lingers on is still an open question.