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After 140 Million Years, Chinese Sturgeons May Soon Be Extinct
By Jason Bittel
More than 16 feet long and weighing up to 1,100 pounds, Chinese sturgeons are among the world's largest freshwater fish. They're big and they're ancient. According to fossil records, they've been swimming China's Yangtze, Qiantang, Minjiang and Pearl Rivers since the time of the dinosaurs.
And now they're on the brink of oblivion, having disappeared from all of their former range except for small portions of the Yangtze.
Over the millennia, humans have sought out these freshwater leviathans not so much for their flesh as for the thousands of tiny black pearls that can be found within the adult females—in other words, caviar.
China began regulating sturgeon fishing in the 1970s, when the full breeding population had been whittled down to just 10,000 individuals. The move saved the species from extinction, but alas, in recent decades an even more existential threat has cropped up.
Dams. So many dams.
Chinese sturgeons are what's known as anadromous fish. Like salmon, they spend part of the year in the ocean and part of the year plying freshwater rivers and streams on the way to their ancestral breeding grounds. But unlike salmon, Chinese sturgeon don't die after spawning. Instead, after they mix up their DNA through an exchange of sperm and eggs in shallow waters upriver, they beat fin back to the sea. Under normal conditions, a Chinese sturgeon can live up to 20 years—spawning again and again and again.
Now, imagine you're a huge fish that's been swimming up a river for a decade and change, just like your anfishestors have for millions of years, and one day you run into a concrete wall.
That's what happened to Chinese sturgeon in 1981 when the Gezhouba Dam began operating on the upper reaches of the Yangtze River. The dam shortened the sturgeon's annual migration by 730 miles. Amazingly though, the fish still managed to breed. Well, somewhat. According to a study published in Current Biology this month, the reproductive output of the local population dropped by more than 75 percent after the dam was in place.
But the sturgeon swam on, making do with their new, shortened home range, since scientists at the time decided there was no good reason to install a device that would allow for fish passage.
Then in 2003, the Three Gorges Dam was stretched across the Yangtze, again with no fish passage device. And then in 2012, the Xiangjiaba Dam went up, followed by the Xiluodu Dam the very next year.
As each new structure divided the river into ever smaller sections, the Chinese sturgeon population flatlined. Their current annual rate of reproduction is now estimated at between 4.5 percent and zero.
The walls themselves aren't the only problem the dams bring for the fish. Dams create large reservoirs of water behind them that soak up heat from the sun. This creates layers of varying water temperatures within the river, similar to a really big lake, says Stephanie Januchowski-Hartley, an environmental biologist at Swansea University in Wales who studies the ecological impact of dams. (Januchowski-Hartley was not part of the study.)
When the dams discharge these reserves, they can have an enormous effect on water temperatures downstream. Numerous factors come into play, such as which depth layer of water is discharged and at what time of year, but in the end, these fluctuations can muck up the sturgeon's internal workings. (Oh, and climate change isn't helping matters, according to the paper's authors.)
"Not all fish like it hot," said Januchowski-Hartley. Not only can higher water temperatures stress out cold-water fish, but the drastic difference between what they're used to and what they're getting seems to affect the rate at which the fish's gonads mature.
Historically, the fish would have had a long, progressively colder swim in which their bodies slowly shifted into reproductive mode. But now their access to the river has been cut by so much that they're jumping right into mating without all the physiological foreplay they've evolved to require. And it just isn't working. According to the new paper, there may be just 156 mature fish left in all of the Yangtze River.
The Chinese government invested heavily in repopulating the Yangtze with more than nine million sturgeon fry, or juveniles, between 1983 and 2007, but scarcely any survived. The researchers refer to these efforts as "inadequate and unsustainable" because the government kept adding new fish but did nothing to enable those fish to reproduce.
No one expects that any of these dams are going to come down anytime soon. But there is still a modicum of hope for returning the fish's spawning habitat to a proper breeding temperature. For example, dam managers could selectively release water from the reservoir that is an agreeable temperature for life downstream, or perhaps churn up the standing water in a way that mixes the layers of different temperatures. Leaving tributaries that pour into the Yangtze undammed could also help keep the temperature steady. Studies have shown that in areas just below a confluence with an undammed tributary, sturgeon spawn better and insects are more prevalent, which suggests that naturally flowing tributaries can create pockets of suitable habitat for all kinds of wildlife.
All these strategies fall into creating what's called an environmental flow, says Januchowski-Hartley, but she has doubts they'll be enough to save the sturgeon over the long term.
But something needs to be done—and quick. If not, the study's authors predict the Chinese sturgeon will likely go extinct within the next 10 to 20 years. Which means that after 140 million years on this planet, the generation of Chinese sturgeon alive today would be the last.
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By Jennifer Molidor, PhD
Climate change, habitat loss and pollution are overwhelming our planet. Thankfully, these enormous threats are being met by a bold new wave of environmental activism.
Trump Makes Strange Claim About Water Efficient Toilets: 'People Are Flushing Toilets 10 Times, 15 Times'
President Donald Trump mocked water-efficiency standards in new constructions last week. Trump said, "People are flushing toilets 10 times, 15 times, as opposed to once. They end up using more water. So, EPA is looking at that very strongly, at my suggestion." Trump asked the Environmental Protection Agency (EPA) for a federal review of those standards since, he claimed with no evidence, that they are making bathrooms unusable and wasting water, as NBC News reported.
By Carey Gillam
Former Monsanto Chairman and CEO Hugh Grant will have to testify in person at a St. Louis-area trial set for January in litigation brought by a cancer-stricken woman who claims her disease was caused by exposure to the company's Roundup herbicide and that Monsanto covered up the risks instead of warning consumers.
A powerful volcano on Monday rocked an uninhabited island frequented by tourists about 30 miles off New Zealand's coast. Authorities have confirmed that five people died. They expect that number to rise as some are missing and police officials issued a statement that flights around the islands revealed "no signs of life had been seen at any point,", as The Guardian reported.
"Based on the information we have, we do not believe there are any survivors on the island," the police said in their official statement. "Police is working urgently to confirm the exact number of those who have died, further to the five confirmed deceased already."
The eruption happened on New Zealand's Whakaari/White Island, an islet jutting out of the Bay of Plenty, off the country's North Island. The island is privately owned and is typically visited for day-trips by thousands of tourists every year, according to The New York Times.
My god, White Island volcano in New Zealand erupted today for first time since 2001. My family and I had gotten off it 20 minutes before, were waiting at our boat about to leave when we saw it. Boat ride home tending to people our boat rescued was indescribable. #whiteisland pic.twitter.com/QJwWi12Tvt— Michael Schade (@sch) December 9, 2019
Michael Schade / Twitter
At the time of the eruption on Monday, about 50 passengers from the Ovation of Seas were on the island, including more than 30 who were part of a Royal Caribbean cruise trip, according to CNN. Twenty-three people, including the five dead, were evacuated from the island.
The eruption occurred at 2:11 pm local time on Monday, as footage from a crater camera owned and operated by GeoNet, New Zealand's geological hazards agency, shows. The camera also shows dozens of people walking near the rim as white smoke billows just before the eruption, according to Reuters.
Police were unable to reach the island because searing white ash posed imminent danger to rescue workers, said John Tims, New Zealand's deputy police commissioner, as he stood next to Prime Minister Jacinda Ardern in a press conference, as The New York Times reported. Tims said rescue workers would assess the safety of approaching the island on Tuesday morning. "We know the urgency to go back to the island," he told reporters.
"The physical environment is unsafe for us to return to the island," Tims added, as CNN reported. "It's important that we consider the health and safety of rescuers, so we're taking advice from experts going forward."
Authorities have had no communication with anyone on the island. They are frantically working to identify how many people remain and who they are, according to CNN.
Geologists said the eruption is not unexpected and some questioned why the island is open to tourism.
"The volcano has been restless for a few weeks, resulting in the raising of the alert level, so that this eruption is not really a surprise," said Bill McGuire, emeritus professor of geophysical and climate hazards at University College London, as The Guardian reported.
"White Island has been a disaster waiting to happen for many years," said Raymond Cas, emeritus professor at Monash University's school of earth, atmosphere and environment, as The Guardian reported. "Having visited it twice, I have always felt that it was too dangerous to allow the daily tour groups that visit the uninhabited island volcano by boat and helicopter."
The prime minister arrived Monday night in Whakatane, the town closest to the eruption, where day boats visiting the island are docked. Whakatane has a large Maori population.
Ardern met with local council leaders on Monday. She is scheduled to meet with search and rescue teams and will speak to the media at 7 a.m. local time (1 p.m. EST), after drones survey the island, as CNN reported.
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