Chinese scientists are engaged in a critical effort to conserve one of the last remaining large animal species inhabiting the Yangtze River, with a comprehensive fishing moratorium playing a pivotal role in their endeavors.
At the Institute of Hydrobiology in Wuhan, a mere 5 kilometers (3.1 miles) from the river’s edge, the preserved remains of the now-extinct baiji river dolphin and paddlefish stand as somber reminders behind glass.
“With those species now extinct, our focus is on safeguarding the Yangtze finless porpoise,” Professor Wang Xi told the BBC. “It has become our most vital concern.”
The last known baiji perished in 2002, after 22 years of care at the Institute. A year later, the last known paddlefish, a ray-finned species capable of growing to over 3 meters, was accidentally caught by fishermen. Despite being tagged and released, it disappeared.
The present objective is to prevent the Yangtze finless river porpoise, estimated to number 1,200 in the wild, from meeting a similar fate.
“It’s the river’s last top predator,” Professor Wang explained. “Their rarity reflects the overall health of the ecosystem.”
Professor Cao Wenxuan of the Chinese Academy of Sciences (CAS) initially proposed a complete fishing ban in 2006, but it required sustained advocacy from fellow scientists before a full 10-year ban was implemented nearly five years ago.
Enforced by police, the ban carries potential prison sentences for those caught fishing in the Yangtze and its adjacent lakes and tributaries. It has caused significant disruption, displacing 220,000 fishermen.
Despite these efforts, the finless porpoise, an ancient member of the porpoise family, remains critically endangered.
Specimens at the Institute are held in captivity for CAS study. They can be viewed from above or below the water, via a staircase leading to an observation area beside a deep tank.
Scientists report that the porpoises become excited around humans, and they certainly seem to be displaying, racing and swimming rapidly near the glass, appearing to observe onlookers with a playful demeanor.
In the wild, they persist where other species have not.
The construction of the Three Gorges Dam in 2006 did not directly impact the finless porpoise, as they do not migrate upstream to spawn, though it did affect their food supply.
For other large marine species like the paddlefish and Chinese sturgeon, the dam proved catastrophic.
Wang Ding, an International Union for Conservation of Nature (IUCN) member specializing in cetaceans, has dedicated his career to the Yangtze’s health. He acknowledges both the benefits and drawbacks of the dams, recalling the river’s former state.
“During flood season, we had to assemble a team to monitor the riverbanks, guarding against potential floods,” he recounted. “Everyone would work to reinforce the levees against the rushing water.”
Now, he notes, the Three Gorges Dam provides flood control.
Professor Wang points out that the massive dam prevents the Yangtze’s giant sturgeons from reaching their spawning grounds.
While the endangered fish briefly found an alternative spawning location, this is no longer the case. Today, sturgeons are only present due to researcher releases of 10,000 at a time.
Despite over a million captive-bred sturgeon being released into the Yangtze last year, efforts to boost the population have failed, as the fish are not reproducing independently in the wild.
To prevent the finless porpoise from suffering a similar fate, Professor Wang and other scientists hope the current fishing ban will be extended beyond its initial 10-year term.
Their research, published in the Bulletin of the Chinese Academy of Sciences, documents a significant increase in fish populations since the ban’s implementation in 2021.
Another threat to the finless porpoise, however, may be more difficult to address.
Wang Xi noted that “ships are very dangerous for animals brains because they are very noisy”.
This creates underwater noise pollution that distresses the animals.
Chinese scientists believe that ship noise may have contributed to the extinction of the Yangtze’s baiji river dolphins, which relied on sonar for communication.
While banning fishing is feasible, halting the busy river traffic vital to central China’s economy is another matter.
Relocating chemical factories away from the Yangtze has proven more attainable. Thousands have been shut down or relocated over the past decade, significantly improving water quality.
Community involvement also plays a role in porpoise preservation.
After retiring, Yang He became an amateur photographer. He now visits the river daily with his camera, seeking to spot the animals.
He sends his best shots to the scientists, who consider him more effective than most at tracking the porpoises’ progress.
Mr. Yang recounted rescuing a porpoise entangled in netting. He alerted local authorities, who closed that section of the river to shipping. The rescued porpoise was pregnant, a fact that made him feel particularly gratified.
Porpoise population numbers provide the most compelling evidence.
In the 1990s, there were 3,300 finless porpoises in the wild. By 2006, this number had halved.
With the fishing bans and factory relocations, the decline halted. Over the past five years, porpoise numbers have increased by nearly a quarter.
Scientists are proud of these figures and their implications for broader environmental health.
“We’re saving the finless porpoise to save the Yangtze River,” said Wang Ding. “They are a great indicator of our success in protecting this ecosystem.”
“If the porpoises are thriving, it signals that the entire river’s ecological health is improving.”
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