A lingering drought in the lower and middle reaches of China's Yangtze River has endangered the survival of aquatic animals, including the river's dolphins, an environmental expert said Tuesday.

Dropping water levels have caused habitat losses for freshwater animals, disrupted the food chain and even put some species under the threat of extinction, Hu Weiyong, deputy director of the National Aquatic Wildlife Conservation Association, said at a press conference.

The situation for freshwater mammals is more serious and it is now a pressing task to save the Yangtze River dolphins and finless porpoise, which are both under state protection, Hu said.

The aquatic expert said that the Yangtze is a good example of biodiversity, as it is home to half of China's protected aquatic animals.

Hu and other aquatic wildlife experts called for efforts to crack down on illegal fishing and firmly control environmentally hazardous dredging projects.

The latest statistics from the China Meteorological Administration showed that between March 1 and May 30, the amount of precipitation in regions along the lower and middle reaches of Yangtze River was 52.8 percent less than average levels.

According to results from satellite monitoring surveys conducted on Saturday, the surface area of the Yangtze's Poyang Lake was 66 percent smaller than last year's recorded surface area, while Dongting Lake saw its surface area shrink by 69 percent in comparison with records from last year. Both lakes are located in the Yangtze's lower and middle reaches.