Sturgeon could SHOULD be listed as endangered species, but Wisconsin’s congressional reps want an exemption. Here’s why.

Paul A. Smith, Milwaukee Journal Sentinel

Thu, Dec 14, 2023, 

A bipartisan group of Wisconsin's congressional delegation has urged the U.S. Fish and Wildlife Service to exempt lake sturgeon in the state from any potential listing under the federal Endangered Species Act.

The agency is conducting a status review of lake sturgeon in the U.S. to determine if listing is warranted; it is scheduled to release its findings by June 30, 2024.

A federal listing under the ESA could prohibit angling for or spearing the fish in Wisconsin. The state hosts annual hook-and-line and spearing seasons for lake sturgeon managed by the Department of Natural Resources.

It a statement issued Dec. 7 the six U.S. representatives and two senators highlighted the robust sturgeon population in Wisconsin, the strong state-based management program as well as the cultural, ecological and economical values of the fish.

"Nowhere in the world will you find such a unique cultural connection and staunch dedication to the preservation of sturgeon population levels than in Wisconsin," the group wrote. "In fact, due to such careful management, populations in the state thrive and allow for a sustainable spear harvest season on the Winnebago System every winter. We are concerned that a potential listing of the species under the Endangered Species Act could curtail this successful, science-based management model as well as threaten a cherished and unique Wisconsin tradition."

Republican Rep. Mike Gallagher, whose district includes part of the Winnebago System, led the effort on the statement. It was also signed by Republican Reps. Scott Fitzgerald, Glenn Grothman,, Bryan Steil, Tom Tiffany and Derrick Van Orden as well as Democratic Sen. Tammy Baldwin and Republican Sen. Ron Johnson.

In 2018 the USFWS received a petition from the Center for Biological Diversity requesting the agency list the lake sturgeon range-wide or as several distinct population segments.

The next year the agency concluded the petition presented "substantial scientific or commercial information indicating listing may be warranted" and initiated a status review process, according to a statement from Melissa Clark, USFWS public affairs specialist.

The USFWS is actively engaged in the review and is gathering and referencing the "best scientific and commercial data available, which includes information regarding States’ management practices for lake sturgeon throughout the range of the species," Clark said.

Lake sturgeon are one of the oldest fish species in North America and are native to at least two dozen states in the central, southern and eastern U.S. according to the USFWS. In Wisconsin they are found in Lakes Michigan and Superior as well as the Wisconsin, Chippewa and Flambeau, Wolf and Fox rivers, among others.

The Wisconsin congressional delegation said the importance of the prehistoric fish is rooted in the Menominee Tribe’s strong cultural ties to the lake sturgeon. The tribe includes sturgeon in its creation story and also relied on the fish as a food source.

The species declined over the last century in many parts of its historical range due to pollution, overfishing and loss of access to spawning habitat.

But several populations are exceptions, including the Detroit River and Lake St. Clair in Lake Huron in Michigan, the Rainy River and Lake of the Woods in Minnesota and the Winnebago System in Wisconsin, said Ron Bruch, retired DNR fisheries director and former sturgeon biologist.

After a period of closed seasons in the early 20th Century due to concerns of overharvest, the sturgeon population in the Winnebago System (lakes Butte des Morts, Poygan, Winnebago and Winneconne and the Fox and Wolf rivers) has grown to become one of the largest in the world, Bruch said.

Fisheries staff with the U.S. Fish and Wildlife Service net a lake sturgeon for processing at Bamboo Bend on the Wolf River in Shiocton. The fish were measured, sexed and had a passive integrated transponder (PIT tag) implanted and then released back to the river.

More: Outdoors calendar

The DNR establishes a sturgeon population estimate each year using a mark and recapture process. In 2022 the population was estimated at 12,304 adult females and 24,061 adult males, as well as an undetermined number of juvenile fish, according to the DNR sturgeon stock assessment report.

And strict regulations limit the harvest of sturgeon to ensure the health of the population, Bruch said.

"The sturgeon population in the Winnebago System is as large now as any time after settlement times," Bruch said. "It's strong and naturally-reproducing. In no way is it threatened or endangered."

The two-week sturgeon spearing season is responsible for an estimated $3.5 million economic impact and sturgeon conservation is a major part in the over $200 million annual impact fishing brings to the Winnebago System, according to the Wisconsin congressional members.

In 2023 the DNR sold 13,219 sturgeon spearing licenses and 1,405 sturgeon were registered over the 16-day spearing season in February on the Winnebago System.

A hook-and-line sturgeon season is held in fall on many major river systems in the state. Anglers are allowed to keep one fish per year but most fishing is catch-and-release. The statewide harvest of sturgeon during the fall season has averaged 33 fish over the last 15 years, according to the DNR. The hook-and-line season is not held on the Winnebago System.

Money raised from the sale of sturgeon spearing and fishing licenses is used to fund Wisconsin sturgeon management programs.

A representative for the Center for Biological Diversity, the organization that asked for the review, said it's most likely the most imperiled populations – Lake Superior, Missouri River, Ohio River, Arkansan-White River, and lower Mississippi, in their view – would get listed.

"The loss of lake sturgeon has been analogous to the slaughter of the buffalo," said Jeff Miller, senior conservation advocate for CBD. "Now there are only nine populations in entire U.S. with more than 1,000 adult fish."

However, Miller said his group doesn't oppose a DNR-managed harvest season in the Winnebago System.

"We don’t see any problem with the short spear-fishing fishery in the Lake Winnebago System and the Upriver Lakes," Miller said. "It hosts a large population of lake sturgeon, and there are strict regulations and quotas."

But the CBD would like to see added protections for sturgeon in other parts of Wisconsin, including lakes Michigan and Superior and their tributaries as well as the Chippewa River.

Lake sturgeon swim along the rocky shore of the Wolf River at Bamboo Bend in Shiocton. The fish congregate at the site to spawn in spring.

If lake sturgeon were listed under the ESA, the U.S. Fish and Wildlife Service could still allow state fisheries to hold harvest seasons with a fish management plan that is consistent with recovery.

The Wisconsin congressional members asked the Service to to take into "strong consideration the conservation success story of the species in Wisconsin."

"Instead of imposing a nationwide, one-size-fits-all listing that could curtail the state’s management plan and threaten a long-cherished tradition, we ask that Wisconsin lake sturgeon be exempt from any potential ESA listing," they wrote. "Furthermore, we encourage the Service to engage with the Wisconsin DNR, local communities, and other relevant stakeholders to help expand this model to other states and ensure the continued existence of lake sturgeon for generations to come."

The statement by members of Wisconsin's congressional delegation follows an October letter with a similar message signed by 29 members of the state legislature.

A public comment period will be held after the Service issues its findings in June 2024.

This article originally appeared on Milwaukee Journal Sentinel: Lawmakers want Wisconsin sturgeon exempt from endangered species list

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White sturgeon-Columbia River’s largest anadromous fish


Thu, December 1, 2022 
Wild Files: It’s our Nature
By Chadd Cawson Local Journalism Initiative Reporter

Sturgeon have been around for over 200 million years, working their way through the waters while dinosaurs roamed the earth. Like salmon they are an anadromous fish with 27 species worldwide and are the primary source for the delicacy caviar. White sturgeon are the largest anadromous fish in Canada and are only found in B.C. They can be easily identified from the dual rows of four to eight ganoid bony plates and despite their name are often a grey or brownish shade on their dorsal side. They have barbels which are located near the snout anterior to their mouths.

Seen swimming in many of our Columbia Valley waterways such as our upper Columbia River, and some of it’s tributaries like Arrow, Slocan, and Kootenay lake to name a few. White sturgeon is native to the Pacific coast which is why they are only found throughout B.C. but unlike their swimming buddies, Pacific salmon white sturgeon do not die upon spawning and often live to be over years 100 old.

When it comes to their own diet they feed on shellfish, crustaceans, small fish like herring and shad, insects, and gastropods but aside from humans can also make a tasty dinner for sharks, sea lions and other marine mammals. In the sturgeon world males mature faster sexually than females and are ready to spawn between the age of 12 and 18 years old. For female white sturgeon they don’t reach their full maturity to spawn until they reach between 25 and 30 years old.

Female sturgeon has many suitors and will have their eggs fertilized by many males during spawning season which happens between May and July. When a female releases her eggs, they develop an adhesive coat and are negatively buoyant upon contact with water. Dependent on the water’s temperature hatching of these eggs can take anywhere from three to 13 days. After the egg incubates, they go through the larvae and fry stage before becoming a juvenile sturgeon which at that time can become more independent with it swimming and feeding. This their last stage before maturing into full adults, when first becoming juveniles, they are typically only 10 cm long.

Quite a catch

White sturgeon have a reputation for being a challenge to catch. They can reach lengths of up to 610 cm with an average mass weighing over 500 kg. White sturgeon are considered quite rare with data showing they have seen quite a population decline over the last 30 years. Schools, or groups of white sturgeon are made up of seniors these days rounding the age of a century as they navigate the waters, one could say they are old school. When one does reel one of these remarkable ancient beauties in on the Columbia River it is intended to be recreational with an expectation to catch and release. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed White Sturgeon in B.C. as threatened with declines particularly in both the Fraser and Columbia River.




Fish tales

All fish are vital to Indigenous people for their survival and sustainability. While sturgeon may not be considered as sacred as salmon, they still certainly hold their place. In some cultures, and folklore, the Sturgeon Moon is connected to how abundant sturgeon once were, and easy to catch come the end of summer. Because of the sheer size of sturgeon, a single catch would feed many. On record the largest white sturgeon ever caught dates to the 1800’s and weighed just over 680 kg, and needed the aid of horses to reel it in.

Chadd Cawson, Local Journalism Initiative Reporter, The Columbia Valley Pioneer

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 #ANTHROPOCENE #SIXTHEXTINCTION 

Researchers announce extinction of the Chinese paddlefish

The paper well illustrates the factors behind the disappearance of the Chinese Paddlefish; and they sound all too familiar to those affecting sturgeon in other rivers such as the Danube. Credit: Flickr Biosiversity Photo Database, Yangtze Museum

The new decade 2020 began with the sad announcement that another species is now extinct—the Chinese Paddlefish (Psephurus gladius), a close relative of the sturgeon family. A paper by Chinese scientists concluded (based on IUCN criteria) that after 200 million years, the "Panda of the Yangtze" which reached up to 7m is now gone from the Yangtze forever. Although the paper received wide coverage in international media, unfortunately it only marked the scientific notification of a fate already sealed and known for some time. In fact, the authors estimated that the paddlefish went extinct somewhere in 2005–2010. The last time a live specimen was found was in 2003. Ten years before that (1993), scientists announced that the species was already "functionally extinct," meaning that for lack of mates it could not reproduce anymore. Therefore, the newest paper did not write a surprise ending for this sad story. Experts have been well aware of the situation for many years.

The paper well illustrates the factors behind the disappearance of the Chinese Paddlefish; and they sound all too familiar to those affecting sturgeon in other rivers such as the Danube. In particular, the combined effects of overfishing and the disruption of migration routes by both small and large dams without proper consideration for fish migration continue to have severe negative impacts on these species. On the Danube, the situation is best represented by the Iron Gates Dams.

The Chinese paddlefish population has been in gradual decline over the last century. Even so, until the 1970's, up to 25 tons of paddlefish were still harvested annually. When the Three Gorges and Gezhouba Dams were constructed on the Yangtze River in the 1980s without any fish passes, they cut off the paddlefish spawning grounds and sealed their fate.

The Danube River, which was historically the home to six distinct sturgeon species, is no exception to this repeating story. The European Atlantic sturgeon (Acipenser sturio) already disappeared long time ago from its entire Black Sea range. The last specimen was found in 1991 in the Rioni River in Georgia. This sturgeon is also sometimes referred to as the common sturgeon, since it was once found all across Europe. Today it is extirpated from all its entire range except in the Gironde-Dordogne-Garonne Basin in France. Less than 800 wild common sturgeons are thought to survive. A breeding and release programme is in place, but due to a very low number of fish in the breeding stock, it has not been very effective.

When the Three Gorges and Gezhouba Dams were constructed without any fish passes, they cut off the paddlefish spawning grounds. Credit: Flickr Biosiversity Photo Database, Liu Chen Han

Action might also come too late for the ship sturgeon, another species once native to the Danube River system. Given that only three known specimens have been caught since 2000, most experts consider the ship sturgeon functionally extinct in the Danube River Basin.

Down from six to four!? None of the four remaining Danube sturgeon species are doing great either. If anything, these past stories should be ringing alarm bells in Europe, and in particular in the Black Sea Region. Currently, the Lower Danube and the Rioni River are the only rivers on the European continent where sturgeon that need to migrate between salt and freshwater environment still reproduce naturally. Only the sterlet, a pure freshwater species, can also be found upstream from the big and unpassable Danube dams such as the Iron Gates or Gabcikovo.

"There is so much more we want to learn about these fascinating fish, but we are running out of time and we know already well enough what measures need to be taken and that we need to take them now, in order to prevent their extinction"—Beate Striebel, WWF Sturgeon Initiative leader.

As time is literally ticking for sturgeon, the Pan European Action Plan for Sturgeon Conservation clearly outlines what needs to be done. A year ago, governments signed up to this plan under the Bern Convention and the European Habitats Directive. It is time to follow up on these commitments. Otherwise we will soon read about similar stories like the one about the Yangtze Paddlefish.

Background

The only remaining relative is the American paddlefish, found in the Mississippi River Basin. Credit: Kevin Schafer / WWF 

The Chinese paddlefish was the largest predatory freshwater fish; one of only two paddlefish species in existence. The only remaining relative is the American paddlefish, found in the Mississippi River Basin in the United States. Almost nothing is known about its biology and ecology. Chinese paddlefish could reach 3-7 m (23 ft) in length and weigh up to 300-500 kg (https://en.wikipedia.org/wiki/Chinese_paddlefish) Both paddlefish species are closely related to the sturgeon family, of which 85 percent are threatened with extinction; making them the most endangered group of species globally.

WWF is engaged in sturgeon protection measures in most Danube countries. Sturgeons used to be present in almost all European rivers, but today seven out of the eight species of sturgeon on the European continent are threatened with extinction. Sturgeons have survived the dinosaurs, but now teeter on the brink of extinction. The Black Sea Region is crucial to the survival of these species in Europe. The Danube and the Rioni River in Georgia are the only two rivers remaining in Europe where migrating sturgeons reproduce naturally. The main reasons are overfishing and loss of habitat through dams that block migration routes or in-river constructions, facilitating navigation. These are often detrimental to the feeding and spawning habitats, necessary for sturgeon survival. Within the EU the only river with naturally reproducing sturgeon populations remains the Danube. Crucial but no longer reproductive stocks are left in the Po River in Italy and the Gironde in France. Restocking activities take place in Bulgaria, Hungary, Romania, France, Germany, Poland, Austria and the Netherlands. Our priority is to identify and protect the critical habitats of the remaining four sturgeon species (Huso huso, Acipenser stellatus, A. ruthenus, A. gueldenstaedtii) in the Lower Danube and north-western Black Sea, as well as to reduce pressure on their remaining populations by addressing poaching and ensuring protection.WWF releases 11,000 sturgeons to restock Danube

 

Half of tested caviar products from Europe are illegal, and some aren’t even caviar

Peer-Reviewed Publication

CELL PRESS

 

IMAGE: 

A PILE OF STURGEONS BEING SOLD AT A FISH MARKED IN EASTERN EUROPE.

view more 

CREDIT: WWF GEORGE CARACAS

Wild caviar, a pricey delicacy made from sturgeon eggs, has been illegal for decades since poaching brought the fish to the brink of extinction. Today, legal, internationally tradeable caviar can only come from farmed sturgeon, and there are strict regulations in place to help protect the species. However, by conducting genetic and isotope analyses on caviar samples from Bulgaria, Romania, Serbia, and Ukraine—nations bordering the remaining wild sturgeon populations—a team of sturgeon experts found evidence that these regulations are actively being broken. Their results, publishing on November 20 in the journal Current Biology, show that half of the commercial caviar products they sampled are illegal, and some don’t even contain any trace of sturgeon.

“The conservation status of the Danube sturgeon populations renders each individual important for their survival, and the observed intensity of poaching undermines any conservation effort,” write the researchers, led by Arne Ludwig of the Leibniz-Institute for Zoo & Wildlife Research.

In Europe, there are four remaining sturgeon species, including Beluga, Russian, stellate, and sterlet, that are capable of producing caviar. The last remaining wild populations of these species in the European Union can be found in the Danube River and the Black Sea. Each species has been protected since 1998 under CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora. In 2000, their CITES listing was accompanied by a strict, international labeling system for all caviar products designed to stop illegal trade. Despite these protections, it was widely known from local anecdotal accounts that illegal poaching is still happening, cites the team, even though no formal investigations had been conducted.

To find out the true source of the commercially sold caviar products being produced in native sturgeon regions, the researchers bought caviar both online and in person from a wide variety of sources including local markets, shops, restaurants, bars, and aquaculture facilities. They also included five samples that had been seized by authorities. In total, they collected and analyzed 149 samples of caviar and sturgeon meat.

After analyzing each sample’s DNA and isotope patterns, the team found that 21% of the samples came from wild-caught sturgeons and that these wild-caught fish were sold in all of the countries studied. They also found that 29% of the samples violated CITES regulations and trade laws, which included caviar that listed the wrong species of sturgeon or the wrong country of origin, and categorized another 32% of samples as “customer deception,” such as samples declared as wild products that actually originated from aquaculture.  

“Our results indicate an ongoing demand for wild sturgeon products, which is alarming, since these products endanger wild sturgeon populations,” write the researchers. “The persistent demand fuels poaching and indicates that consumers do not fully accept aquaculture products as a substitute. In addition, caviar being sold in violation of CITES and EU obligations questions the effectiveness of controls in general and the labeling system in particular.”

Three of the samples, served in Romania in a dish called “sturgeon soup,” weren’t sturgeon at all. Instead, the researchers identified the fish as European catfish and Nile perch.

The authors suggest that the large volume of illegal poaching activity could be an indicator that local seafood vendors are lacking adequate income opportunities, which might increase the pressure to engage in illegal fishing activity.  They also point to the fact that there is likely a lack of effective law enforcement in these regions, either because stopping illegal poaching isn’t a priority for local authorities or because they don’t have the tools to prove a fish’s illegal origin. But regardless of the reasons, they stress the importance of taking action, and quickly.

“Although poaching and illegal wildlife trade are often considered a problem in developing countries, these findings bear evidence that a high ratio of poached sturgeon products originates from EU and accession candidate states,” write the authors. “The control of caviar and sturgeon trade in the EU and candidate member states urgently needs improvement to ensure that Danube sturgeon populations will have a future.”

###

This research was supported by funding from an EU-LIFE project.

Current Biology, Ludwig et al. “Poaching and illegal trade of Danube sturgeons.” https://www.cell.com/current-biology/fulltext/S0960-9822(23)01316-7

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Sturgeons being descaled for sale at an Eastern European fish market.

CREDIT

WWF George Caracas

---

JOURNAL

Current Biology

DOI

10.1016/j.cub.2023.09.067 

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Poaching and illegal trade of Danube sturgeons

ARTICLE PUBLICATION DATE

20-Nov-2023

FOSSIL FISH
Sudden die-off of endangered sturgeon alarms Canadian biologists

White sturgeon (Acipenser transmontanus) in the Fraser River.

 Photograph: Cavan Images/Alamy

The deaths within days of 11 sturgeon, a species unchanged for thousands of years, have puzzled scientists

Leyland Cecco in Toronto

THE GUARDIAN
Mon 26 Sep 2022

When the first spindly, armour-clad carcass was spotted in the fast-flowing Nechako River in early September, Nikolaus Gantner and two colleagues scrambled out on a jet boat, braving strong currents to investigate the grim discovery.

Days later, the remains of 10 others were spotted floating along a 100km stretch of the river in western Canada.

In total, 11 endangered white sturgeon have mysteriously died in a short period of time, blindsiding biologists, who are trying to save a fish teetering towards extinction.

The species has remained relatively unchanged in 200m years: toothless apex hunters that glide gracefully in a handful of British Columbia’s rivers. To navigate the murky waters, sturgeon gently brush whisker-like barbels that hang from their snout along the gravelly bottom.

White sturgeon, with a torso clad in five distinct bony plates called scutes, look every inch a prehistoric fish. The largest ever recorded reached 20ft long and another, believed to be 104 years old, weighed nearly 1,800 lbs.

The Nechako River, where the sturgeon population has dropped from 5,000 to 500 in the past century. Photograph: Fernando Lessa/Alamy

“When you see a massive head appearing through the murky water and the eyes look at you, it’s just incredible to see this majestic animal alive,” said Gantner, a senior fisheries biologist with the British Columbia government. “And you gain respect for it, knowing that most fish we see are older than us.”

The rapid succession of deaths has taken an unexpected emotional toll on Gantner and his colleagues.

“I’m deeply saddened. These last couple of weeks, I feel like I’m going through grief,” he said. Each time he and colleagues tenderly move the hulking carcasses of the fish from the shore to the freezer and on to the necropsy table, he feels a pang of sorrow. “I don’t think I felt like that from other fish that I’ve worked with.”

So far, there are no obvious answers. The team hasn’t found any sign of trauma nor evidence of chemical exposure, disease, or angling-induced death.

“Whatever it is, it affects larger sturgeon, not other species. It’s constrained to a place in time and space. So that gives us some clues,” said Steve McAdam, a biologist with the province’s ministry of land, water and resource stewardship. “In a way, it’s easier to rule a bunch of stuff out than to rule some things in.”

The deaths in the Nechako are particularly painful for McAdam, who studied a similar die-off in the lower Fraser River in 1993 and 1994, when the region lost 36 fish in two years.

A battery of tests that followed that die-off was inconclusive, said McAdam; the events occurred in differing ecosystems, hundreds of kilometres apart, offering limited clues to investigators.

Because the team investigating the current episode has a narrow window of time to recover dead sturgeon before decomposition sets in and destroys valuable clues, they have appealed to the public for help. In a region where the fish have deep cultural ties to First Nations and are part of the curriculum in local schools, residents have paid close attention to the phenomenon.

A range of theories have been suggested, including a belief that elevated water temperatures are to blame. But McAdam said previous hot summers had not triggered similar die-offs.

“There’s no end to the ideas. There are some partial explanations, but we’re really trying to keep an open mind and not veer too far down one path,” he said.

To navigate in murky waters, sturgeon gently brush whisker-like barbels that hang from their snouts along the gravelly bottom.

 Photograph: Minden Pictures/Alamy

Before the mysterious die-offs, white sturgeon, which are listed as a federal species at risk, were already in trouble.

Over the last century, the numbers in the Nechako River have dropped from more than 5,000 to only 500. Soon after a dam was built on the Nechako River in 1957, the species experienced what biologists call “recruitment failure” – new fish weren’t being added to the population.

It is from within that ageing population, already missing an entire generation of fish, that the 11 have died.

Overfishing, drainage projects and dam construction have all contributed to the collapse. On all the rivers in the province where sturgeon once thrived, dams have crushed their populations. Only the Fraser River, the largest without a dam, has a relatively healthy sturgeon population in the tens of thousands.

British Columbia has worked since 2001 to help the species recover, drawing teams of provincial and federal biologists, First Nations groups and the industries tied to sturgeon habitat loss, like hydroelectric dam operators.

Efforts include using hatcheries, a “stopgap measure” to help the population recover, as well a longer-term goal of restoring habitat.

But the sudden death of 11 members of a species already spiralling towards demise mirrors a trend all over the world: sturgeon have become the most threatened genus of fish.

All of the 26 remaining species of sturgeon are now at risk of extinction. They are the victims of overfishing; in some species, like beluga sturgeon, the roe is prized as caviar. And the habitats they have persisted in are disappearing.

“They are a quite a charismatic species and it’s a fish that has been around for millions of years. So you don’t take it lightly when it’s in danger,” McAdam said.

The abruptness with which the fish have died has puzzled biologists in part because white sturgeon have been closely studied and monitored for the last three decades, precisely because of their precarious situation.

“And then within a week, this happens. We have a new huge question mark,” said Gantner. “It’s really blindsided us.”

Both Gantner and McAdam were hopeful that the deaths will serve a broader end, providing valuable insight to biologists into what might have happened – and how a similar outcome can be prevented in the future.

Because the other option – that they have already reached some kind of a tipping point – is too bleak to consider.

“We’ve never done the experiment of eliminating them fully and seeing how truly important sturgeon are to an ecosystem,” said McAdam. “And personally, I don’t think we ever want to.”

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Across China: Scientists witness first wild reproduction of Yangtze sturgeon after decades of conservation


Source: Xinhua
Editor: huaxia
2025-06-16 



GUIYANG, June 16 (Xinhua) -- The video footage was simple but extraordinary -- a tiny, half-translucent grey larva, no bigger than a grain of rice, wriggled out of its egg casing in the shallow waters of the Chishui River in southwest China's Guizhou Province.

To an untrained eye, it might have looked like just another fish hatching. But for the team of scientists watching anxiously, this fragile creature represented something far greater: the first successful natural reproduction of the critically endangered Yangtze sturgeon in the wild in over two decades.

This breakthrough was the culmination of years of painstaking efforts by researchers from the Institute of Hydrobiology (IHB) of the Chinese Academy of Sciences, the Chinese Sturgeon Research Institute under the China Three Gorges Corporation, and other institutions, organized by the Ministry of Agriculture and Rural Affairs. Their ultimate goal is to revive a species on the brink of extinction.

The Yangtze sturgeon, a nationally protected first-class animal, was once a vital part of the river's ecosystem. However, by the early 2000s, water pollution, overfishing and other factors had pushed it to the edge. In 2022, the International Union for Conservation of Nature declared the species extinct in the wild. The last known natural reproduction occurred in 2000.

Yet, scientists refused to give up. They spent years developing techniques to restore the sturgeon's spawning grounds. They experimented with reconstructing water flow patterns and riverbed conditions, first in controlled environments, then in a side branch of the Yangtze River in Jiang'an County, southwest China's Sichuan Province, in 2023 and 2024.

"Due to the lack of historical data, at first we didn't know what environmental conditions were needed for the reproduction of the Yangtze sturgeon. However, after repeated experiments, this problem has been basically solved," said Liu Huanzhang, an IHB researcher whose study focuses on fish conservation biology.

Those small successes gave them hope -- but the real test would be whether the fish could reproduce in a completely natural setting, since no hatched larvae had been found in these experiments.

Their eyes turned to the Chishui River, one of the tributaries of the upper Yangtze. Unlike much of the mainstream of the Yangtze River, the Chishui River is relatively untouched by industrial development and remains undammed in its mainstream.

In early 2025, the team began its most ambitious project. At a site near Chishui City, they meticulously reshaped a stretch of the riverbed, using drones, sonar and hydrological modeling to recreate the exact conditions sturgeons need for spawning.

"We dug channels to mimic natural currents, carefully selected gravel and sand for the river bottom, and created an 8,000-square-meter spawning ground tailored to the fish's needs," said Liu Fei, an associate researcher at the IHB.

On April 3, they released 20 adult sturgeons -- 10 males and 10 females -- into the modified habitat. Then came the waiting. For days, scientists monitored the fish around the clock using underwater cameras and sonar, watching for any sign of mating behavior.

On the night of April 12, the signals lit up -- the sturgeons were gathering in the channels. By dawn, the team had spotted fertilized eggs and estimated that over 200,000 eggs were scattered in the spawning ground. Under microscopic analysis, researchers confirmed the eggs were developing normally.

On April 16, the first hatchlings emerged -- tiny, wriggling proof that the Yangtze sturgeon could still reproduce in the wild.

The success of the test has proven that mature individuals in the artificially bred Yangtze sturgeon population have the ability to reproduce in the wild, said Liu Huanzhang. "This lays the foundation for the full restoration of the species' natural reproduction in the river."

"This isn't just about saving one species," said Liu Fei. "The sturgeon is rather giant in waters, and adults may reach over one meter in length. Its survival reflects the health of the entire ecosystem. This success gives us a model for restoring other endangered aquatic species."

The breakthrough in the Yangtze sturgeon's natural reproduction in the Chishui River marks a pivotal achievement in conservation efforts, though it represents just the beginning of a long-term recovery process.

The researchers stated that they will continue to monitor the growth of the young sturgeons in their natural habitat while refining protection strategies.

"These efforts will not only restore the Yangtze sturgeon population but also contribute to the overall health and stability of the Yangtze River ecosystem," Liu Huanzhang added. ■

Dabry's sturgeon

Species of fish

Dabry's sturgeon, also known as the Yangtze sturgeon, Changjiang sturgeon and river sturgeon, is a species of fish in the sturgeon family, Acipenseridae. It is endemic to China and today restricted to the Yangtze River basin, but was also recorded from the Yellow River basin in the past. It was a food fish of commercial importance. Its populations declined drastically, and since 1988, it was designated an endangered species on the Chinese Red List in Category I and commercial harvest was banned. It has been officially declared extinct in the wild by the IUCN as of July 21, 2022.

Dabry's sturgeon
Conservation status
Extinct in the Wild (IUCN 3.1)
CITES Appendix II (CITES)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acipenseriformes
Family:	Acipenseridae
Genus:	Sinosturio
Species:	S. dabryanus
Binomial name
Sinosturio dabryanus(Duméril, 1869)
Synonyms
Acipenser dabryanus Duméril 1869