Focus on Arts and Ecology

Habitat loss, dams, and pollution threaten the survival of the 'world's forgotten fishes.'

They may not get as many headlines as pandas, polar bears, and big cats, but freshwater fish deserve their moment in the spotlight, say conservationists. They’re critical for human survival, yet one-third of them are threatened with extinction according to a new report released by 16 global conservation organizations.

In “World’s Forgotten Fishes,” researchers offer details about the Earth’s 18,075 freshwater fish species, which are more than half of all fish species and a quarter of all vertebrate species in the world.1 They point out that 80 freshwater fish species have been classified as extinct by the International Union for Conservation of Nature (IUCN) Red List, including 16 species just in 2020.

According to the report, freshwater fisheries provide the primary source of protein for 200 million people in Asia, Africa, and South America and provide jobs for 60 million people. Recreational fishing generated more than $100 billion each year, while fisheries are a $38 billion industry.

But there have been devastating changes in some populations of freshwater fish with migratory freshwater fish dropping 76% since 1970. Mega fish (those heavier than 30 kilograms or 66 pounds) have had a 94% decline.

Michele Thieme, lead freshwater scientist at World Wildlife Fund (WWF), one of the groups that published the report, has been studying the deterioration in the freshwater ecosystem for years.

“The data speaks clearly — our rivers are in peril,” Thieme tells Treehugger. “Two-thirds of the world’s longest rivers are impeded by dams and other infrastructure. That means only one-third of our world’s rivers remain well connected from source to sea. The fragmentation of freshwater ecosystems makes it difficult for freshwater fish to migrate freely and adapt to rapidly changing environments.”

It’s no surprise then, that freshwater fish populations are suffering so much, she says. Some of the contributing factors include habitat destruction, dams on free-flowing rivers, over-abstraction of water for irrigation, and domestic, agricultural, and industrial pollution. 

Safeguarding Freshwater Fish

Freshwater fish don’t get the attention as fluffier animals or even other fish

“It is possible that the ‘out of sight out of mind’ phrase applies to freshwater fish. They live below the often murky surface of rivers and lakes” Thieme says.

“They don’t live next to vibrant visible corals like many of their saltwater counterparts ... Freshwater fish are critical to the web of life, and without them, we’ll see broader ecosystems crumble.”

Of the 80 global freshwater extinctions, 19 of those were in the U.S., more than any other country.

“The U.S. has already dammed most of our medium and long rivers, which has had obvious impacts on our freshwater fish populations,” Thieme says.

“There are countries that are at pivotal moments in planning their energy grids. They still have the opportunity to explore wind and solar energy options or plan their hydropower developments in more sustainable ways that do not obstruct the flow of rivers and the migration of fish. They can avert a lot of the damage that we have already done to our rivers and freshwater fish.”

A team of conservation experts outlined an emergency recovery plan for freshwater diversity in the Convention on Biological Diversity (CBD)’s 5th Global Biodiversity Outlook report. The key components include sustainably managing and rebuilding fisheries, protecting critical habitats, and reducing pollution.

Conservationists hope what's been dubbed a New Deal for Nature and People will build on the pillars outlined in that plan.

“The good news is that we know what needs to be done to safeguard freshwater fishes. Securing a New Deal for the world’s freshwater ecosystems will bring life back to our dying rivers, lakes and wetlands,” Stuart Orr, WWF global Freshwater Lead.

“It will bring freshwater fish species back from the brink too — securing food and jobs for hundreds of millions, safeguarding cultural icons, boosting biodiversity and enhancing the health of the freshwater ecosystems that underpin our well-being and prosperity.”

(Sources: Treehugger)