Goodbye River Monsters: Scientists Declare Two of the World’s Larger Freshwater Fish Extinct

Written by Colby Maxwell
Updated: January 24, 2023
© Alneth / CC BY-SA 4.0 – License / Original
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Key Facts

  • Contrary to popular belief, rivers also contain creatures capable of rivaling those that live in oceans in terms of size.
  • The Yangtze sturgeon considered a living fossil is now only available in breeding farms.
  • The Chinese paddlefish which was one of the largest freshwater fishes on the planet, is however extinct.

Many of Earth’s greatest creatures became extinct once humans came along and began using them as a “resource.” Unfortunately, it happens more than we realize. Current estimates place the current biodiversity loss at around 150 unique species a day, a truly shocking number. Sadly, that trend continues, and two recent examples show it a little too well. Let’s discover the two river monsters that scientists have officially declared extinct.

Two of the World’s Largest Freshwater Fish Have Officially Been Declared Extinct

Goodbye River Monsters: Scientists Declare Two of the World's Larger Freshwater Fish Extinct
Both the Yangtze sturgeon and the Chinese paddlefish were declared extinct in 2022.

©Alneth / CC BY-SA 4.0 – License

A “river monster” isn’t really what it sounds like at first. The expression was popularized by the show that shares the name, but it simply means a massive freshwater fish that lives in a river. We generally consider the ocean the home of large fish, but lurking beneath the rapids of some rivers are creatures that rival some of the larger fish in the oceans.

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Among those “river monsters” are the Yangtze sturgeon and the Chinese paddlefish. These fish deemed “the last giants of the Yangtze,” have been officially declared extinct by scientists. These amazing fish have lived in the Yangtze River for a very long time, with some estimates placing the Yangtze sturgeon as a 140 million-year-old tenant. The Yangtze sturgeon was generally considered a living fossil (like many other surgeons) and had the typical bony and elongated appearance that most surgeons share. The Chinese paddlefish was known for its long silver body and long snout that it sensed prey with.

The Yangtze sturgeon still has hope, albeit slim. There are still some captive fish that are held in tanks and breeding programs around the region. So far, however, any attempts at placing these farmed fish into the wild have failed.

The paddlefish, sadly, has no future. There are no captive specimens, and no tissue samples were ever taken of these fish. As such, they are now permanently extinct.

What Caused the Yangtze Sturgeon and Chinese Paddlefish to Go Extinct?

Goodbye River Monsters: Scientists Declare Two of the World's Larger Freshwater Fish Extinct
The Three Gorges Dam is the largest dam in the world.

©isabel kendzior/

The fish have been living in the river for longer than humans have been around, but their sharp decline can be traced to the construction of the river’s first dam back in the 1980s. Once the dam was constructed, both fish began their decline. The Yangtze sturgeon had a migratory path that spanned from the East China Sea to where it spawned, just above the dam. The structure blocked the pathway for the fish, slowing reproduction. The Chinese paddlefish was last seen around the Three Gorges Dam in 2003, showing just how detrimental they were to native wildlife.

Aside from the damming, the fish were also the victims of overfishing. Ancient Chinese emperors considered the paddlefish a delicacy, while the caviar of the sturgeon was extremely valuable. Overfishing, combined with pollution and damming, were the final nails in the coffin for the last of the Yangtze river monsters.

All About the Yangtze Sturgeon

CAPTION: The Yangtze sturgeon (also known as the Chinese or Dabry’s sturgeon) is only alive on breeding farms and not in the wild.

Specimen of a Yangtze sturgeon
Specimen of the Yangtze sturgeon, aka Chinese or Dabry’s sturgeon, which has been declared to be extinct in the wild

©CC BY-SA 4.0 – License

How Big Was the Yangtze Sturgeon?

The Yangtze sturgeon is considered one of the larger freshwater fish in the world. They can reach lengths of up to 8.2 feet and are known to weigh upwards of 40 lbs.

Where Did the Yangtze Sturgeon Live?

The Yangtze sturgeon had a historical range that encompassed the entire Yangtze River basin. They are known to spawn in the upper regions of the basin and travel down towards the East China Sea.

What Did the Yangtze Sturgeon Eat?

These sturgeon are known as “benthic” predators, meaning that they mostly eat along the bottom. They are known to eat crustaceans, mollusks, small fish, and insects.

All About the Chinese Paddlefish

Goodbye River Monsters: Scientists Declare Two of the World's Larger Freshwater Fish Extinct
The Chinese paddlefish was one of the largest freshwater fish in the world.

©Alneth / CC BY-SA 4.0 – License

How Big Was the Chinese Paddlefish?

The Chinese paddlefish was quite a bit larger than the sturgeon. They have been recorded up to 23 feet long and was recognized as one of the largest freshwater fish in the world. The maximum weight recorded was around 660 lbs.

Where Did the Chinese Paddlefish Live?

The Chinese paddlefish was found exclusively in the Yangtze River basin and the estuaries around the East China Sea. It would generally stay in the river but would also venture into lakes around the area.

What Did the Chinese Paddlefish Eat?

The Chinese paddlefish mostly ate other fish, namely anchovies, gobies, catfish, and even flounder. They also occasionally ate crabs and shrimp.

Discover More River Monsters!

The Featured Image

Chinese paddlefish in museum
© Alneth / CC BY-SA 4.0 – License / Original

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About the Author

Colby is a freelance writer from Charlotte, North Carolina. When he isn't distracted by his backyard birdfeeder, you can find him camping, exploring, and telling everyone around him about what he's recently learned. There's a whole world to learn about and Colby is content to spend his life learning as much as he can about it!

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