Chinese sturgeons artificially bred in Shanghai. (ZHANG HAIFENG/FOR CHINA DAILY)

Researchers from the Shanghai Aquatic Wildlife Conservation and Research Center have successfully bred Chinese sturgeon through artificial insemination for the first time, hatching nearly 5,000 fry of the endangered species.

At around 10 pm on Oct 1, the center's base in Shanghai's Chongming district saw the first artificially bred Chinese sturgeon hatchling emerge after over 100 hours of incubation, followed by thousands more in the ensuing days.

As of Oct 8, the very first fry had grown to 18 millimeters in length, with all other newborn sturgeons from the same cohort showing healthy development. This is the first time that Shanghai has artificially bred Chinese sturgeon.

"After 20 years of efforts, we've finally artificially bred Chinese sturgeon in Shanghai with our own hands, thanks to the Yangtze River protection initiatives," said Zheng Yueping, deputy director of the research center.

Chongming island, where the research center is located, sits at the mouth of the Yangtze River.

The Chinese sturgeon, revered as a "living fossil" crucial to understanding fish evolution, has roamed the rivers for some 140 million years. Despite being wildlife under first-class protection in China, its ability to naturally reproduce in the wild had ceased. In July 2022, the International Union for Conservation of Nature declared the Yangtze sturgeon extinct in the wild.

In 2021, the center launched its program to master artificial sturgeon breeding techniques. After forming a special task force in late 2023, researchers embarked on a process to select and prep suitable parent fish.

Overcoming setbacks like sub-par fish health, the team refined water conditions, feed sources and temperature controls through trial and error.

Their effort finally paid off when 13 parent fish suitable for artificial breeding — eight males and five females — were greenlighted after health checks for the attempt in mid-September this year.

On Sept 24, four adult male Chinese sturgeons and four female ones were chosen and inseminated across two batches to maximize chances of success.

Promptly adjusting workflows enabled the researchers to overcome hurdles like difficulties inducing ovulation and unsynchronized egg development during this critical period.

The center will further optimize experimental procedures and standardize techniques, laying the groundwork for the next research phase and future large-scale artificial breeding of Chinese sturgeons in Shanghai.

While this marks Shanghai's first artificial sturgeon reproduction, other institutions across the Yangtze River basin are also actively engaged in such conservation efforts for this endangered species.

According to the Ministry of Agriculture and Rural Affairs, more than 1 million artificially bred Chinese sturgeons have been released this year as of June.