A sad farewell: They survived the dinosaurs but were no match for mankind
A stranded Chinese paddlefish photographed in the 1990s.
Wei Qiwei, an aquatic life scientist, said he was saddened but not surprised that the Chinese paddlefish has been officially declared extinct.
In fact, the Yangtze River Fisheries Research Institution researcher came to the same death-knell conclusion 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 had become extinct sometime between 2005 and 2010, based on decades of study.
"The last wild Chinese paddlefish we spotted was in 2003," he said. "It was over three meters long, and we estimated it was in its 20s -- middle age for the species. Yet we never found any other individual since then."
He added, "Now 20 years later, that last paddlefish might have gone as well. When the last individual dies, the species is considered extinct."
The real question for Wei is: What's next?
Aquatic and amphibian and even reptile life, especially mid-to-large-size species, is under threat in the Yangtze River. Dabry's sturgeon, or the Yangtze sturgeon, has already been listed as extinct by the international conservation union. Baiji, or Yangtze white-fin porpoise, is deemed "possibly extinct" in the wild, with its population relying entirely on artificial reproduction. The Yangtze finless porpoise, Yangtze alligators and Chinese giant salamanders are considered critically endangered.
Although they belong to different classes, these species have much in common. They lived in the Yangtze for tens of millions of years before the effects of human activities in recent decades led them to breeding difficulties that decimated their populations.
The Chinese paddlefish was one of the largest and oldest freshwater fish in the world. Its origins could be traced back to Early Cretaceous, some 120 million years ago. It outlived dinosaurs but couldn't survive modern society.
Wei began studying the Chinese paddlefish in 1984, five year before it was listed as first-class protected animal in the country.
"Back then, dead bodies of the fish were spotted from time to time in Yichang and Jingzhou in Hubei Province," Wei said. "Some were caught by fishermen; some were killed by ship propellers."
A Chinese paddlefish specimen is displayed at the Beijing Natural History Museum. The species has been declared extinct.
According to Wei, the extinction of the paddlefish was caused by overfishing, river shipping and dam building. The same factors threaten other aquatic species.
"The Chinese paddlefish is an example of fish that externally fertilize," Wei explained. "The fertilization needed a spawning ground with suitable water flow speed and temperature. The larvae usually foraged for food in the lower reaches of the river, and after they sexually matured, they would migrate back to the upper reaches for spawning."
In the 1970s, the construction of the Gezhouba Dam in Yichang section of the Yangtze River blocked the migration passageway. At the same time, overfishing in the river decreased the fish's food sources, and their large bodies were especially prone to injury from ships.
"I remember several Chinese paddlefish encounters in the 1990s," Wei said. "They had been hurt by ships or fishing nets. None survived. In 2002, we received an emergency call from Nanjing and rushed there to find the fish dead. That one lived for only 29 more days."
The last time encounter with the fish in 2003 was actually a hopeful one. In Yibin in Sichuan Province, a paddlefish was caught by a fishing net by accident. It recovered soon after Wei and his team treated it, so Wei tagged it and released it back to the river.
"We wanted to track it and find its spawning ground, but we eventually lost contact with it," Wei said. "We tried to find it for the next decade, but the effort was in vain. Our hope became the last good-bye."
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 ensuring that the same mistakes aren't made with the Chinese sturgeon.
A Chinese sturgeon born from artificial reproduction is released into the Yangtze River.
Nicknamed "king of Yangtze fish," the Chinese sturgeon is at most 5 meters long. Even older than the Chinese paddlefish, its fossils have been dated back as far as 145 million years. Its larvae grow in the East China Sea or the South China Sea, and migrate to the upper reaches of the Yangtze River to spawn.
The fish was once popular on Chinese dinner tables, but after Gezhouba Dam was built, its population dropped. Although new spawning sites formed below the dam, the population never fully recovered.
"We've long been monitoring the natural reproduction of Chinese sturgeon," said Wei. "Some years we found some eggs; some years we didn't. Unfortunately, we haven't found any natural reproduction of the sturgeon for the past five consecutive years."
However, artificial reproduction for the fish started early, and now a "seed" of the species is 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 sturgeon extinction, to encourage its natural reproduction and, ultimately, to restore the population back to the average historical levels.
"We know that the latter could actually be a wish instead of a realistic goal," he said. "Rapid development of human society and intensive human activities certainly affect the living environment of animals, and what we need to acquire a balance between the two. It is a lesson that the entire human race should learn."
A Chinese finless porpoise was spotted in the Yangtze River in Yichang in October 2021.
His prognosis is sadly true. The lives of freshwater aquatic species face the threat of extinction worldwide. The latest "red list" alert issued by the International Union for Conservation of Nature shows that all of the world's remaining 26 sturgeon species are now at risk 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 bans major new development projects on the river to protect its ecological system.
Fishing on the river is also strictly controlled.
In 2002, the Ministry of Agriculture and Rural Affairs designated closed fishing seasons on various parts of Yangtze River, including those in the city of Chongqing and in the riverfront provinces of Yunnan, Guizhou, Sichuan and Hubei. In 2020, fishing was entirely banned for a decade.
The ban gives rise to the possibility that not only fish but also their food cycle will be restored. The Chinese finless porpoise has directly benefited from the decree.
The finless porpoise, which looks somewhat like a dolphin, was once on the verge of extinction. In 2018, its population was estimated at only about 1,000, with numbers dropping.
Today its population is gradually growing back. Although no official statistics have been published, many finless porpoises were reported in the past two years in various sections of the Yangtze River.
"It would be much better if we returned 30-40 percent of the Yangtze River's functions back to the nature," said Wei. "Giving up fishing is a good beginning."
