Quarter of world's freshwater fish species at risk of extinction, researchers warn

Thousands of species of freshwater fish are at risk of extinction, the International Union for Conservation of Nature said in a Monday report released at the United Nations climate conference in Dubai.

The organization assessed just under 15,000 species and found 25% face possible extinction. At least 17% of the threatened species are impacted by climate change. Rising sea levels are causing seawater to move up rivers, the IUCN said. Freshwater species are also threatened by pollution, overfishing, invasive species, disease, dams and water extraction. Pollution impacts 57% of freshwater fish species at risk of extinction, the organization said.

More than half of the world's known fish species live in freshwater, according to Kathy Hughes, co-chair of the IUCN freshwater fish specialist group. She said they're integral to the ecosystem. 

"This is essential to the billions of people who rely upon freshwater ecosystems, and the millions of people who rely on their fisheries," Hughes said. "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."

Around the world, at least 200 million people rely on freshwater fish as their major source of protein, the World Wildlife Fund said in 2021. 

The IUCN assessment found that the global population of Atlantic salmon, which are classified as near threatened, decreased by 23% between 2006 and 2020. Salmon live in both fresh and saltwater.

"Climate change affects all stages of the Atlantic salmon's life cycle, influencing the development of young salmon, reducing prey availability and allowing invasive alien species to expand their range," the organization said. "Dams and other barriers block access to spawning and feeding grounds, while water pollution and sedimentation, primarily from logging and agriculture, lead to higher mortality of young salmon."

It isn't just freshwater species at risk. The IUCN said its updated Red List of Threatened Species now includes 157,190 species, of which 44,016 are threatened with extinction.

"Climate change is menacing the diversity of life our planet harbors, and undermining nature's capacity to meet basic human needs," IUCN Director General Dr. Grethel Aguilar said. 

In:
• Climate Change

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBSNews.com. She has previously written for outlets including PIX11 News, The New York Daily News, Inside Edition and DNAinfo. Aliza covers trending news, often focusing on crime and politics.

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