Thanks to Wei Qiwei
Wei Qiwei, an aquatic scientist, said he was sad but not surprised that the Chinese paddlefish is officially extinct.
In fact, the researcher from the Yangtze River Fisheries Research Institution came to the same death knell in a paper published in 2019, three years before the official announcement from the International Union for Conservation of Nature.
At the time, Wei hypothesized that the fish went extinct sometime between 2005 and 2010, based on decades of research.
“The last wild Chinese paddlefish we saw was in 2003,” he said. “It was over ten feet long and we estimate it was in her twenties — middle age for the species. Yet we have never found another individual since.”
He added: “Now, 20 years later, that last paddlefish may also be gone. When the last individual dies, the species is considered extinct.”
Li Yi, Lu Feiran / SHINE
The real question for Wei is: what now?
Aquatic life, amphibians and even reptiles, especially medium to large species, are threatened in the Yangtze River. Dabry’s sturgeon, or the Yangtze sturgeon, has already been declared extinct by the International Conservation Union. Baiji, or Yangtze whitefin porpoise, is considered “possibly extinct” in the wild, with the population reliant entirely on assisted reproduction. The Yangtze finless porpoise, Yangtze alligators and Chinese giant salamanders are considered critically endangered.
Although they belong to different classes, these species have a lot in common. They lived in the Yangtze for tens of millions of years before the effects of human activities over the decades brought them to breeding problems that decimated their populations.
The Chinese paddlefish was one of the largest and oldest freshwater fish in the world. Its origins date back to the early Cretaceous, about 120 million years ago. It survived the dinosaurs, but could not survive modern society.
Wei began studying the Chinese paddlefish in 1984, five years before it was listed as the first-class protected animal in the country.
“At the time, dead bodies of the fish were seen from time to time in Yichang and Jingzhou in Hubei Province,” Wei said. “Some were caught by fishermen, others were killed by ship propellers.”
According to Wei, the extinction of the paddlefish was caused by overfishing, river navigation and building dams. The same factors threaten other aquatic species.
“The Chinese paddlefish is an example of fish that fertilize externally,” explains Wei. “The fertilization required a spawning ground with an appropriate water flow rate and temperature. The larvae usually foraged for food in the lower reaches of the river, and after reaching sexual maturity, they migrated back to the upper reaches to spawn.”
In the 1970s, the construction of the Gezhouba Dam in the Yichang section of the Yangtze River blocked the migration passage. At the same time, overfishing in the river reduced the fish’s food sources, and their large bodies were particularly prone to injury from ships.
“I remember several encounters with Chinese paddlefish in the 1990s,” Wei said. “They were injured by ships or fishing nets. None of them survived. In 2002, we received a distress call from Nanjing and rushed there to find the fish dead. It only lived for 29 days.”
The last encounter with the fish in 2003 was actually hopeful. In Yibin, Sichuan Province, a scoop fish was accidentally caught by a fishing net. It recovered shortly after Wei and his team treated it, so Wei tagged it and released it back into the river.
“We wanted to track it and find its spawning ground, but we ended up losing contact with it,” Wei said. “We tried to find it for the next ten years, but the effort was in vain. Our hopes became the last goodbye.”
He said his biggest regret is that artificial reproduction of the fish was not carried out early enough to save the breed. Now his priority is to make sure the same mistakes are not made with the Chinese sturgeon.
Nicknamed “king of the Yangtze fish”, the Chinese sturgeon is up to 5 meters in length. Even older than the Chinese paddlefish, fossils are up to 145 million years old. The larvae grow in the East China Sea or South China Sea and migrate to the upper reaches of the Yangtze River to spawn.
The fish was once popular on Chinese dining tables, but after the Gezhouba Dam was built, the population declined. Although new spawning grounds formed under the dam, the population never fully recovered.
“We’ve been tracking the natural reproduction of the Chinese sturgeon for a long time,” Wei says. “Some years we found eggs, some we didn’t. Unfortunately, we haven’t found a natural reproduction of the sturgeon for the past five consecutive years.”
Artificial reproduction for the fish, however, started early, and now a “seed” of the species has been preserved — at least for the present.
Earlier this year, 50,000 Chinese sturgeon larvae born from artificial reproduction were released into the Yangtze. Scientists are now waiting to see if the fish will reproduce naturally.
According to Wei, the goals are to prevent the extinction of the sturgeon, stimulate natural reproduction and ultimately bring the population back to the average historical level.
“We know that the latter could actually be a wish rather than a realistic goal,” he said. “Rapid development of human society and intensive human activities certainly affect the habitat of animals, and what we need to achieve a balance between the two. It is a lesson that all humanity should learn.”
His prognosis is unfortunately true. The life of freshwater aquatic species is threatened with extinction worldwide. The latest warning from the International Union for Conservation of Nature’s “red list” shows that all of the world’s 26 remaining sturgeon species are now in danger of extinction, up from 85 percent in 2009.
In a desperate race to reverse the trend, China enacted the Yangtze River Protection Law, which came into effect in March 2021. It prohibits major new development projects on the river to protect the ecological system.
Fishing on the river is also strictly controlled.
In 2002, the Ministry of Agriculture and Rural Affairs instituted closed fishing seasons for several parts of the Yangtze River, including those in Chongqing City and Yunnan, Guizhou, Sichuan, and Hubei River Provinces. In 2020, fishing was completely banned for ten years.
The ban has the potential to restore not only fish but also their food cycle. The Chinese porpoise has directly benefited from the decree.
The finned porpoise, which somewhat resembles a dolphin, was once on the brink of extinction. In 2018, the population was estimated to be only about 1,000, with the number declining.
Today, the population is gradually growing back. Although no official statistics have been published, many porpoises have been reported in various parts of the Yangtze River over the past two years.
“It would be much better if we return 30-40 percent of the Yangtze River’s functions to nature,” Wei said. “Giving up fishing is a good start.”