Populations of migratory freshwater fish, essential to the health of rivers and maintaining the livelihoods of millions of people, are plummeting and at risk of collapse, a major UN assessment warned on Tuesday.
Habitat destruction, overfishing and water pollution from the Amazon to the Danube threaten the very survival of hundreds of species whose epic journeys along the world’s great rivers go largely unnoticed.
Freshwater fish face multiple threats, says the report published at the opening of the COP15 summit on migratory species in Brazil, placing them “among the most imperiled vertebrates”.
Populations of the Mekong giant catfish, European eel and various species of sturgeon are among those that have been decimated in recent decades due to human pressures, including dam building and caviar harvesting.
Some – including the Chinese paddlefish – have already been declared extinct, while others are functionally dependent on captive breeding stocks and reintroductions to support wild populations.
The number of migratory freshwater fish has fallen by about 81% since 1970, according to conservation organization WWF.
These fish – a vital source of protein for humans and animals around the world – need unimpeded passage to move between spawning and feeding grounds, which can cross borders.
This means that international cooperation is needed to stop their decline.
The report from the Convention on the Conservation of Migratory Species of Wild Animals (CMS) identifies nearly 350 species of migratory fish that could benefit from greater protection in the international framework.
Species such as salmon, eel and lamprey will be among those discussed at the March 23-29 meeting in Campo Verde.
Of these, the vast majority are in Asia, followed by South America and Europe.
The river basins considered priorities are the Amazon and La Plata-Parana in South America, the Danube in Europe, the Mekong and the Ganges-Brahmaputra in Asia and the Nile in Africa.
“This assessment shows that migratory freshwater fish are in dire need and that protecting them will require countries working together to keep rivers connected, productive and full of life,” Zeb Hogan, the lead author of the assessment, said in a statement.
