This is 59th release by the Institute since 1980. [Photo: Xinhua]

The Chinese Sturgeon Research Institute has released around 500 captive-bred Chinese sturgeon into a section of the Yangtze River in central China's Hubei Province, with a goal of trying to increase the wild population of the rare species.

The sturgeon, aged between three and six years old, average around 110 centimeters in length and weigh about 5.5 kilograms on average. [Photo: Xinhua]

The sturgeon, aged between three and six years old, average around 110 centimeters in length and weigh about 5.5 kilograms on average, heavier than previous group that were released into the wild.

This is 59th release by the Institute since 1980.

Believed to have lived at the same time as dinosaurs, the Chinese sturgeon has existed for more than 140 million years.

The sturgeon, aged between three and six years old, average around 110 centimeters in length and weigh about 5.5 kilograms on average. [Photo: Xinhua]

However, over-fishing and changes to the environment has pushed the fish toward extinction.

For this reason, China has been learning solutions to breed and preserve the endangered species, and has classified the fish as a species for top national protection since the 19th century.

China has classified the fish as a species for top national protection since the 19th century. [Photo: Xinhua]