The Yangtze River dolphin, also known as the baiji dolphin (Lipotes vexillifer), was a white, fresh-water dolphin native to the Yangtze River and Qiantang River in China as recently as the 1990s.
The baiji is best known for its squinty eyes and a long, toothed, beak-like mouth. Aficionados tell tales of it being the “goddess of the Yangtze,” a symbol of peace and prosperity and the protector of people at sea. But sadly, the creature disappeared more than two decades ago.
After experiencing a dramatic crash in population during the late 1950s, when it started to be hunted for its flesh and skin, the baiji became known as one of the world’s rarest mammal species.
Today, it has not been seen in the Qiantang River since the 1950s. And while scientists spotted at least 400 individuals between 1979 and 1981 in the Yangtze River, a survey in the late 1990s found only 13 animals.
The last record of a confirmed, authenticated sighting in the wild is from 2001 when fishermen found the carcass of a pregnant female baiji in Zhenjiang City. (Several unconfirmed sightings have surfaced since then from fishermen and others.)
The world’s only captive Yangtze river dolphin — a male called Qi Qi — lived at the Institute of Hydrobiology in Wuhan, China, for 22 years after being rescued from a fishing injury, and died in July 2002.
In 2006, when conservationists set out on a six-week long survey of the entire main Yangtze channel where baiji’s had previously been found, they failed to find any evidence that the species survives.
So experts have had to declare the baiji white dolphin “functionally extinct” — meaning that even if some individuals still existed somewhere out there, the population is no longer viable.
Read More: How Do We Know When a Species Is Extinct?
When the team of survey conservationists left the Chinese docks in 2006, they had two ships, each packed with a team of visual observers and acoustic equipment to listen for the whistles of the dolphins.
“As the survey went on, we were seeing finless porpoises which are much harder to see, but we were not seeing or hearing baiji,” says Barbara Taylor, a senior scientist at Southwest Fisheries Science Center who was part of the survey team. “You know, the clock does tick, and it got more and more depressing as time went on. It’s a pretty soul-crushing experience.”
Ever since then, several other surveys have been published about the finless porpoise, but there have not been any confirmed sightings of baiji. “We’ve been waiting to really put, quite literally, the final nails in the coffin for a number of years now,” Taylor says.
On the policy side, a lot of time typically passes between the point when researchers suggest a species has completely died off and when policymakers declare that species extinct.
Most people are familiar with Shakespeare’s Romeo and Juliet story. Taylor says the tragic ending makes an apt illustration for the challenge of declaring a species extinct.
In Shakespeare’s tale, Juliet takes poison to fool people into thinking she’s dead. Unfortunately, she fools Romeo, and he acts on that (false) knowledge and kills himself. Juliet then takes her own life, truly this time, after waking up and realizing her lover is dead.
“If you declare them extinct, and they aren’t really extinct, and you remove all the protections that were in place, then you actually cause the extinction,” Taylor says of the baiji, or similar creatures facing extinction.
This creates a dilemma for conservation scientists who want to accurately describe what is happening to biodiversity.
“It’s really hard to say, especially with marine mammals that are hard to see, whether there’s not even a single pair of them left in the world,” Taylor adds.
The question of whether this is the first time humans directly caused the extinction of a cetacean is the title of the paper describing the scant findings in the 2006 survey, published in Biology Letters.
“We are forced to conclude that the baiji is now likely to be extinct,” the authors wrote. “Unlike most historical-era extinctions of large-bodied animals, the baiji was the victim not of active persecution but of incidental mortality resulting from massive-scale human environmental impacts.”
Boat collisions and dam construction are partially to blame, but constant unsustainable by-catch by fishing companies probably hit the hardest, according to the study.
Rolling hooks and similar fishing gear caused half of all known baiji deaths in the two decades after 1970, research suggests, and 40 percent of deaths during the 1990s were caused by electro-fishing, a practice that literally stuns fish with electricity in order to catch them.
“When we went out and did the survey in the Yangtze, it was like doing a survey in the middle of the Los Angeles freeway,” Taylor says. “It’s just not a natural environment. It is heavily impacted by people, so there’s a whole laundry list of threats [for dolphins].”
The baiji started separating in its evolution from other river dolphins about 20 million years ago.
It developed some unique features, like a stomach divided into three parts, which isn’t exhibited in any other dolphins. Thus, with its extinction, we’ve lost the whole ancient evolutionary branch it represented.
One strategy that might have helped save the baiji is “ex-situ conservation.” This refers to taking a species out of its natural habitat and trying to grow its population in another location.
Researchers did try this with the baiji by taking some dolphins into Yangtze River oxbow lakes — bends of the river sectioned off as designated cetacean reserves. But the initial attempts did not go as planned.
In the 1990s, for example, one dolphin placed in an oxbow lake died after getting stuck in fishing gear that hadn’t been removed, according to the Natural History Museum in the UK.
Continued work on the project fell through due to “unforgivable delays in action” and because virtually no international funds became available, according to Samuel Turvey’s book Witness to Extinction: How We Failed to Save the Yangtze River Dolphin.
“When we went out to find the last of the baiji and take them into those oxbow lakes, they were already gone,” says Taylor, who was recently in San Felipe, Mexico, conducting a survey of the few remaining vaquita — a critically endangered porpoise species in the Gulf of California.
For the baiji, things might have been different if ex-situ conservation began earlier, while plenty of numbers remaining in the wild.
“Certainly, knowing what we know now, you need to start doing those things when there are hundreds of animals,” says Taylor. “I think there was a really good chance that they could have saved baiji.”