Volunteers release Chinese sturgeons to the Yangtze River at Yanzhi Park in Yichang, central China's Hubei Province, April 12, 2015. Photo: Xinhua

Researchers freed 3,000 artificially-bred Chinese sturgeons, a rare fish that has lived through the dinosaur age, into the country's longest river, the Yangtze, to save the species from extinction.

Staff with the Chinese Sturgeons Research Institute released 500 such fish born in 2011 with a body length of 80 cm and 2,500 born in 2013, about 40 cm long each. 

Advanced methods were adopted to help scientists track them simultaneously, according to Gao Yong, deputy head of the institute.

It was the 57th release of the rare fish.

Chinese sturgeons, nicknamed "aquatic pandas", are listed as a wild creature under state protection. 

Due to water projects, busy traffic and pollution, the number of wild Chinese sturgeons which migrate to Gezhouba, Hubei Province, for reproduction, has fallen from about 1,000 in 1982 to about 50, according to estimates of Chinese experts.

Volunteers release a Chinese sturgeon to the Yangtze River at Yanzhi Park in Yichang, central China's Hubei Province, April 12, 2015. Photo: Xinhua
 

A Chinese sturgeon is released to the Yangtze River at Yanzhi Park in Yichang, central China's Hubei Province, April 12, 2015.Photo: Xinhua 
 

Chinese sturgeons are released to the Yangtze River at Yanzhi Park in Yichang, central China's Hubei Province, April 12, 2015.Photo: Xinhua