CHENGDU -- Chinese officials and researchers on Thursday released 80 Dabry's sturgeon into the upper reaches of the Yangtze River in the latest effort to replenish the wild population of the endangered fish.

The release of 80 captive-bred sturgeon, launched by the Ministry of Agriculture and Rural Affairs, took place in the city of Yibin, in Southwest China's Sichuan province.

Officials said that the released sturgeon were all adults, including 40 males and 40 females ready for reproduction, and 24 of them had ultrasonic tracking devices implanted.

Researchers at the Yangtze River Fisheries Research Institute will monitor the released sturgeon's distribution, migration, growth and spawning.

"We conducted the release before the spawning season with a clear goal: to speed up the restoration of the Yangtze River sturgeon population," said Wei Qiwei, chief scientist at the Chinese Academy of Fishery Sciences, which administers the research institute.

Theoretically, there is a high probability that the released group will lay eggs during the spring spawning season, but more monitoring and research are needed to see whether the much-anticipated spawning will actually take place, according to Wei.

Dabry's sturgeon, also known as the Yangtze sturgeon, has lost its natural ability to reproduce since 2000 due to overfishing and crowded rivers, among others. It was classified as critically endangered by the International Union for Conservation of Nature in 2010.

In recent years, China has stepped up efforts to rescue the Dabry's sturgeon and other endangered endemic species in the river, such as Chinese sturgeon, by targeting illegal fishing, closing polluting factories and releasing captive-bred fry into the wild.

According to the Ministry of Agriculture and Rural Affairs, since 2007, China has tried to restore the wild population of the Yangtze sturgeon by releasing captive-bred fish into the river, though the effect has been modest.

However, Wei believes that the improving ecology of the Yangtze River in recent years, the implementation of a 10-year fishing ban in the river, and a recently enacted law on the river's protection have all created favorable conditions for the accelerated recovery of the species.