Migratory freshwater fish populations, vital to the health of rivers and sustaining the livelihoods of millions of people, are in freefall and at risk of collapse, a major United Nations 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 several threats, said the report published at the opening of the COP15 summit on migratory species in Brazil, making them “among the most endangered vertebrates”.
Populations of Mekong giant catfish, European eel and various sturgeon species are among those that have been decimated in recent decades due to anthropogenic pressures that include the construction of dams and harvesting for caviar.
Some—including the Chinese paddlefish—have already been declared extinct, while others are functionally dependent on captive animals and reintroductions to support wild populations.
According to the conservation group WWF, the number of migratory freshwater fish has declined by about 81% since 1970.
These fish – a vital source of protein for humans and animals around the globe – require unhindered passage to move between spawning and feeding grounds, which can span borders.
This means that international cooperation is needed to halt their decline.
The report, from the Convention on the Conservation of Migratory Species of Wild Animals (CMS), identifies nearly 350 migratory fish species that could benefit from greater protection under the international framework.
Species including salmon, eel and lamprey are among those to be considered during the meeting on 23-29. March in Campo Verde.
Of these, the vast majority are found in Asia, followed by South America and Europe.
The river basins considered to be a priority are the Amazon and La Plata-Parana in South America, the Danube in Europe, the Mekong and Ganges-Brahmaputra in Asia and the Nile in Africa.
“This assessment shows that migratory freshwater fish are in serious trouble and that protecting them will require countries to work together to keep rivers connected, productive and full of life,” said Zeb Hogan, lead author of the assessment, in a statement.
