A Chinese sturgeon is released to the Yangtze River at Yanzhi Park in Yichang, central China's Hubei Province, April 12, 2015. A total of 3,000 Chinese sturgeons, a top-level protected species in China which lived at the same time as dinosaurs, were released by the Chinese Sturgeon Research Institute (CSRI) under the China Three Gorges Corporation on Sunday here. Chinese sturgeons, nicknamed "aquatic pandas", are listed as a wild creature under state protection. Researchers with CSRI succeeded in artificially inseminating and spawning of cultured Chinese sturgeons in 2009. Since then fish have been released into the river every year to save the species from extinction. [Photo: Xinhua]

3000 Chinese sturgeons have been released into the Yangtze River in the city of Yichang in Hubei in an attempt to try to increase stocks.

The 3,000 sturgeons were bred by the Chinese Sturgeons Research Institute. The institute has released more than five million of the fish into the wild.

It has implanted sonar marks into 61 selected sturgeons this year in order to trace and monitor their movements. The number of marked sturgeon was 18 last year.

Experts say they haven't detected natural reproduction of the species in the Yangtze River for two consecutive years, indicating the species are facing the danger of extinction.

Gao Yong, Deputy Head of the Chinese Sturgeons Research Institute:

"Actually only one year is very dangerous. The species should keep breeding naturally every year to keep the chain. If they could not breed for several generations, the group would fail to survive. In history, a lot of species tend to become extinct as a result of interval suspension of natural breeding."

Though the artificial breeding program started in 1983, the effectiveness is decreasing due to various factors. Affected by the changing environment, the ratio for female to male of the group reached as high as 10:1. Gao Yong said overfishing and water pollution are other factors that challenge the species.

"The Chinese sturgeon, as well as other aquatic life in the Yangtze River, is facing a very serious challenge, a threat together. At present, the ecological system of the Yangtze River is degrading seriously. The Baiji is extinct, the cowfish endangered and the Chinese sturgeon hasn't had natural reproduction for nearly two years. These illustrates that the ecological environment of the Yangtze River is very bad and this is the biggest problem faced by these species."

The young fish bred through the program would then undergo a month-long adaptation period in the wild before being released to the Yangtze River.

Believed to have lived at the same time as dinosaurs, the Chinese sturgeon, or "acipenser sinensis," has existed for more than 140 million years. The fish, nicknamed "aquatic panda," is a precious but endangered species native to China and has been placed under top-level state protection.

The number of the wild Chinese sturgeons has sharply declined to around 100 from thousands in the 1980s. (CRI)