The Chinese paddlefish is now extinct. It existed before flowering plants, bamboo and the pandas. It reached three metres in length. They could weigh up to 300kg and managed to survive the 5th mass extinction of life on Earth that occurred 66 million years ago. The Chinese paddlefish and its ancestors had been around for 150 million years. It lived in the Yangtse river in what is today China and it used its special sword-like snout to sense electrical activity to find prey, such as crustaceans and other smaller fish.
Chinese paddlefish spent part of their life in the lower section of the Yangtze, including the brackish water of its estuary. In spring they migrated up river and into major tributaries to spawn.
A recent study published in the Science of the Total Environment called “Extinction of one of the world’s largest freshwater fishes: Lessons for conserving the endangered Yangtze fauna” has concluded that the extinction of this species was largely due to overfishing and dam construction.
The study’s leader Qiwei Wei of the Chinese Academy of Fishery Sciences, who has been looking for the animal for decades, said that this is “a reprehensible and an irreparable loss.”
Zeb Hogan, a fish biologist at the University of Nevada, Reno, and a National Geographic Explorer added “This is sad. It’s the definitive loss of a very unique and extraordinary animal, with no hope of recovery.” Hogan continues to say “This is the first of these very large freshwater fish to go and many are at risk—the concern is that more will go extinct, but the hope is that we can reverse their decline before it’s too late,” Hogan says.
The species has been declining over the last century because of overfishing. In the 1970s, 25 tons of paddlefish were caught on average per year. The beginning of the end for this species started with the building of dams in the Yangtze River. The last nail in the coffin was the Gezhouba Dam, built on the main stem of the Yangtze, some thousand miles from the sea. The dam was constructed between 1970 and 1988. Importantly a fish bypass was not included and the paddlefish were thus cut off from their upstream spawning grounds. The population paddlefish above the dam continued to breed whereas the population below the dam, being deprived of their spawning grounds, could not reproduce.
The species was still being found in small numbers in the 1980s, for example, 32 were caught in 1985, and young were maybe seen as recently as 1995. I would venture my own estimate that 150 years ago the population of Chinese paddlefish could have been anything around ten thousand individuals.
Aerial view of the Gezhouba Dam that marked the beginning of the end for the Chinese paddlefish
As can be imagined the populations of the fish continued to dwindle after the 1980’s dam construction. The researchers estimate the fish had become functionally extinct by 1993. Yet another case of human interference in the life cycle of a species, habitat fragmentation and human overkill.
There were several failed attempts to start a captive-breeding population. In 2002, in Nanjing, a female was captured and urgent efforts were made to save her. These were not successful. Later in in 2003, Qiwei Wei and his associates attached a tracking device to a Chinese paddlefish that was accidentally captured near Yibin, south-central China. They released it to see where it might go, but within hours lost all signals from the tag. That was the last Chinese Paddlefish ever seen alive.
Looking back the study team concluded that the best time to have started conservation efforts was before 1993, or at least before the early 2000s. The study concludes that the fish went extinct between 2005 and 2010.
The study team looked for Chinese paddlefish at hundreds of locations along the Yangtze, as part of an ongoing biological survey of the entire river basin. They used various types of nets, sonar, electro-fishing gear and other techniques to locate any individuals of the species, without success.
According to National Geographic “The Chinese paddlefish was one of only two paddlefish species in existence; the only remaining relative is the American paddlefish, a vulnerable species found in the Mississippi River Basin in the United States. Both are closely related to the sturgeon family, of which 85 percent are threatened with extinction, making them the most imperilled group of animals, according to the International Union for Conservation of Nature.”
“We must urgently act to save those species [in the Yangtze River] for which some chance still remains,” said Ivan Jaric, a co-author of the study and biologist at Czechia’s Institute of Hydrobiology and the University of South Bohemia, as in the study team’s survey they didn’t find another 140 species that they hoped to see.