Photograph courtesy Zeb Hogan
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A pair of Chinese sturgeons swims in the Beijing City Aquarium. Capable of weighing half a ton and growing to 16 feet long, this freshwater leviathan is one of the largest sturgeon species on Earth.

Photograph courtesy Zeb Hogan

Chinese sturgeon


One of 17 sturgeon species belonging to the Acipenser genus, Chinese sturgeons have a sharklike form, with large pectoral fins, a rounded snout, and rows of pronounced ridges running the length of their spine and flanks. They’ve lived in China’s Yangtze River for perhaps 140 million years, and this relic of the dinosaur era is sometimes dubbed a "living fossil.”

Chinese sturgeons can grow to enormous proportions, with historical accounts of specimens topping 16 feet and an astounding 1,300 pounds. However, no sturgeons close to that size have been seen for decades, and the species is classified as critically endangered.

Migration and decline

They’re seasoned travelers, making the longest migration of any sturgeon in the world. Every year, these prehistoric fish journey some 2,000 miles from the East China Sea to their spawning grounds in the Yangtze River.

Or, at least they used to. In recent years, this ancient migration cycle has been blocked by the Gezhouba Dam, built in the 1980s. Subsequent dams have placed new, possibly insurmountable, hurdles in the sturgeons’ upstream path and thrown the future of the species into serious doubt.

Heavy shipping traffic, overfishing, and water pollution have also plagued Yangtze River waters and taken a heavy toll on these aquatic behemoths. The species is highly sensitive to increased noise on the river. Studies also show that sturgeons spawning has been negatively affected by warming water temperatures caused by dams.

Some scientists believe that worsening water contamination from industrial runoff and other sources may cause sturgeons to change their sex from male to female.

Historically, Chinese sturgeons were found across Asia, including China, Japan, and the Korean Peninsula, but they have been extirpated from most regions due to habitat loss and overfishing.

Most experts believe very few migratory sturgeons remain in the Yangtze river, the only place where the species is found, and there are fears that wild Chinese sturgeon may soon go extinct like their Chinese paddlefish relatives.

Diet

The adults are predators that consume any aquatic animal that can be swallowed, while the young feed on insects, larvae, and organic compounds. The sturgeons’ reproductive capacity is poor, and it takes more than 10 years for the fish to begin spawning.

There are also reports suggesting the sturgeons may be adapting to their changing environment by shifting from a diet of less abundant bottom dwellers, like clams, to more plentiful earthworms.

Breeding program and conservation

The Chinese sturgeon is called a “national treasure” in China, and its meat is considered a delicacy among Chinese people.

Chinese officials have made efforts to safeguard the sturgeon, including implementing a fishing ban in the 1980s and creating a conservation area below the Gezhouba Dam to serve as an alternative spawning ground.

They have also been running a massive breeding program for decades, with millions of young fish being released into the river. The efforts have met with little success, however, with experts saying very few, if any, of the farmed fish have survived in the wild.

'Giant Fish' Faces Big Trouble in China

Aquatic ecologist and National Geographic Explorer Zeb Hogan explores the threats facing the Chinese sturgeon and efforts underway to save it in this 2007 short video.