SUBSCRIBE TO OUR FREE NEWSLETTER
Daily news & progressive opinion—funded by the people, not the corporations—delivered straight to your inbox.
5
#000000
#FFFFFF
5
#000000
#FFFFFF
freshwater fish
'Shocking' Share of Freshwater Fish Species at Risk of Extinction
"Ensuring freshwater ecosystems are well managed, remain free-flowing with sufficient water, and good water quality is essential to stop species declines... in a climate-resilient world," one scientist said.
Dec 11, 2023
More than 20% of the world's freshwater fish species are in danger of extinction, according to the first-ever assessment of the category by the International Union for Conservation of Nature.
The assessment was released Monday as part of an update to the IUCN Red List of Threatened Species published to coincide with the United Nations Climate Change Conference (COP28). It found that 3,086 out of 14,898 listed freshwater fish species are at risk of disappearing, and at least 17% of threatened fish species are impacted by the climate crisis.
Barney Long, Re:wild's senior director of conservation strategies, said it was "shocking" that such a large percentage of "freshwater fish are now threatened with extinction and that climate change is now recognized as a significant contributing factor to their extinction risk."
"Climate change is menacing the diversity of life our planet harbors, and undermining nature's capacity to meet basic human needs."
The climate crisis can harm freshwater fish by altering seasonal rhythms, lowering freshwater levels, and increasing saltwater intrusion into freshwater ecosystems as sea levels rise. These changes only exacerbate the dangers freshwater fish already face: 57% of at-risk species are threatened by pollution, 45% by dams and water extraction, 33% by disease and invasive species, and 25% by fishing.
"Freshwater fishes make up more than half of the world's known fish species, an incomprehensible diversity given that freshwater ecosystems comprise only 1% of aquatic habitat," Kathy Hughes, co-chair of the IUCN Species Survey Commission Freshwater Fish Specialist Group, said in a statement. "These diverse species are integral to the ecosystem, and vital to its resilience. This is essential to the billions of people who rely upon freshwater ecosystems, and the millions of people who rely on their fisheries."
One example of a fish important to humans that is now at risk is Kenya's large-toothed Lake Turkana robber (Brycinus ferox). This species moved from "least concern" to "vulnerable" on the Red List because of dams, overfishing, and climate change-driven drought.
Another example is the Atlantic salmon, which has seen a "significant overall decline" in its population since around the turn of the 21st century, according to IUCN. This prompted the conservation body to revise its status from "least concern" to "near threatened." Atlantic salmon face a number of threats including dams, runoff pollution from logging and agriculture, diseases from farmed fish, overfishing, and the climate crisis.
"It appears that global climate change, resulting in rising sea, stream, and air temperatures, is a major driver acting on a wide range of factors influencing the Atlantic Salmon's life cycle," one study concluded.
It can do this by driving up stream and river temperatures so that they are too hot for fish to survive; increasing the range of invasive species; prompting fish to migrate early, which can decreases their chances of survival; and reducing prey availability, among other factors.
The overall Red List update also warned of the impacts of the climate crisis on species generally. For example, the Central South Pacific and East Pacific green turtles are now considered "endangered" and "vulnerable" respectively. The climate crisis adds to the stress on these animals by harming the seagrass they eat, threatening to flood nests with sea-level rise, and warming temperatures to an extent that decreases hatching success.
"Climate change is menacing the diversity of life our planet harbors, and undermining nature's capacity to meet basic human needs," IUCN director generalGrethel Aguilar said in a statement. "This IUCN Red List update highlights the strong links between the climate and biodiversity crises, which must be tackled jointly. Species declines are an example of the havoc being wreaked by climate change, which we have the power to stop with urgent, ambitious action to keep warming below 1.5°C."
Conservationists emphasized the importance of protecting freshwater ecosystems in particular.
"Ensuring freshwater ecosystems are well managed, remain free-flowing with sufficient water, and good water quality is essential to stop species declines and maintain food security, livelihoods, and economies in a climate-resilient world," Hughes said.
Long agreed: "It is critical that we better safeguard our freshwater systems as they are not only home to precious and irreplaceable wildlife, but also provide humans with so many services that only the natural world can."
Eating One Freshwater Fish Equals a Month of Drinking Water With 'Forever Chemicals': Study
"The extent that PFAS has contaminated fish is staggering," said the lead researcher, advocating for "a single health protective fish consumption advisory for freshwater fish across the country."
Jan 17, 2023
Yet another study on Tuesday raised the alarm about the dangers of "forever chemicals," revealing that eating just one locally caught freshwater fish in the continental United States can be equivalent to drinking contaminated water for a month.
Per- and polyfluoroalkyl substances (PFAS) are widely called forever chemicals because they persist in the human body and environment for long periods. Despite public health concerns, the manufactured chemicals have been used in products ranging from firefighting foam and waterproof clothing to nonstick pans and food packaging.
"These test results are breathtaking."
Duke University and the Environmental Working Group (EWG) researchers analyzed data for over 500 fish fillet samples collected across the country from 2013-15 for a pair of U.S. Environmental Protection Agency (EPA) monitoring programs: the National Rivers and Streams Assessment and the Great Lakes Human Health Fish Fillet Tissue Study.
"Identifying sources of PFAS exposure is an urgent public health priority," said study co-author and EWG senior scientist Tasha Stoiber in a statement.
"PFAS contaminate fish across the U.S., with higher levels in the Great Lakes and fish caught in urban areas," she noted. "PFAS do not disappear when products are thrown or flushed away. Our research shows that the most common disposal methods may end up leading to further environmental pollution."
Perfluorooctanesulfonic acid (PFOS) contributed significantly to the high levels in the samples. U.S. manufacturers have largely phased out that PFAS, but it has been used in firefighting foam and was a main component of Scotchgard, a fabric protector by 3M—which announced last month that it plans to exit the PFAS market by the end of 2025.
As the new study states:
The two datasets indicate that an individual's consumption of freshwater fish is potentially a significant source of exposure to perfluorinated compounds. The median level of total targeted PFAS in fish fillets from rivers and streams across the United States was 9,500 ng/kg, with a median level of 11,800 ng/kg in the Great Lakes. PFOS was the largest contributor to total PFAS levels, averaging 74% of the total.
"These test results are breathtaking," said Scott Faber, EWG's senior vice president for government affairs. "Eating one bass is equivalent to drinking PFOS-tainted water for a month."
Specifically, the researchers calculated that eating one 8 oz. serving of fish is equivalent to consuming one month of drinking water with PFOS at 48 parts per trillion (ppt), which is 2,400 times the interim U.S. EPA health advisory.
"People who consume freshwater fish, especially those who catch and eat fish regularly, are at risk of alarming levels of PFAS in their bodies," said co-author and EWG senior scientist David Andrews. "Growing up, I went fishing every week and ate those fish. But now when I see fish, all I think about is PFAS contamination."
\u201cOur new paper on high PFAS levels in freshwater fish across the U.S. \n\nshould be a bigger part of the national conversation on PFAS exposure \n\nlevels hundreds of times over those in FDA fish sampling\n\nrelease:\nhttps://t.co/OPBGm9rYI8\n\npaper:\nhttps://t.co/OceSpyc37E\u201d— David Andrews (@David Andrews) 1673962922
The study stresses that "the exposure to chemical pollutants in freshwater fish across the United States is a case of environmental injustice that especially affects communities that depend on fishing for sustenance and for traditional cultural practices."
While the study was published in the journal Environmental Research, EWG's website features an interactive map that details the key findings nationwide.
The researchers found that the median levels of total PFAS in freshwater fish were 278 times higher than those in commercial fish tested by the U.S. Food and Drug Administration from 2019-22.
"It's incredible how different they are," Andrews toldThe Hill. According to the outlet:
Some commercially caught fish may be less contaminated because they are grown in controlled aquaculture environments, Andrews explained. Meanwhile, large-scale ocean fishing often occurs farther offshore, where PFAS pollution would be more diluted, he added.
Andrews acknowledged, however, that the data on commercially caught fish is much more recent than the freshwater contamination figures.
He also recognized that with the industrial phaseout of PFOS production, the pollution "levels in rivers and streams do seem to be decreasing, which is important."
"At the same time, the levels are still so high that any fish consumption likely impacts [human blood] serum levels," Andrews said. "But they are moving in the right direction, which I think is some good news, at least in terms of the rivers and streams."
Despite some progress—including small steps last year by the EPA—the researchers and others pointed to the findings as evidence of the need for further action on PFAS.
"The extent that PFAS has contaminated fish is staggering," said lead researcher Nadia Barbo, a graduate student at Duke. "There should be a single health protective fish consumption advisory for freshwater fish across the country."
\u201cThanks to my friends at @ewg for this important new research on PFAS exposures from fish. We @seneca_lake @riverkeeper asked @NYSDEC to develop fish consumption standards for PFAS when we commented on the proposed PFAS guidance values! @BasilSeggos\u201d— Jill Witkowski Heaps (@Jill Witkowski Heaps) 1673970352
EWG's Faber declared that "for decades, polluters have dumped as much PFAS as they wanted into our rivers, streams, lakes, and bays with impunity. We must turn off the tap of PFAS pollution from industrial discharges, which affect more and more Americans every day."
"The EPA needs to move swiftly to set regulations for the industries most likely to be dumping PFAS into the environment," he added. "Downstream communities especially have suffered the consequences of unregulated PFAS discharges for far too long."
Most Popular
We cover the issues the corporate media never will.
Please support our journalism.