UN assessment warns migratory freshwater fish populations risk collapse

Migratory freshwater fish, essential to healthy rivers and to the livelihoods of millions, are rapidly declining and could face collapse, a major UN assessment warned on Tuesday.

Migratory freshwater fish face mounting pressures

From the Amazon to the Danube, habitat loss, overfishing and water contamination are jeopardising hundreds of species. Their remarkable journeys through the world’s major river systems often receive little attention.

The report, released as the COP15 summit on migratory species opened in Brazil, said freshwater fish are exposed to a range of pressures, placing them “among the most imperiled vertebrates”.

In recent decades, human activities have severely reduced populations of Mekong giant catfish, European eel and several sturgeon species. These pressures include dam building and fishing for caviar.

Some species, such as the Chinese paddlefish, have already been declared extinct. Others now depend in practical terms on captive breeding programmes and reintroductions to maintain their wild populations.

WWF, the conservation organisation, estimates that migratory freshwater fish populations have fallen by about 81 percent since 1970.

These fish provide an important source of protein for people and animals worldwide. They need unobstructed routes between breeding and feeding areas, which may extend across national boundaries.

As a result, international collaboration is necessary to halt their decline.

Protection priorities across major river basins

The assessment from the Convention on the Conservation of Migratory Species of Wild Animals (CMS) highlights almost 350 migratory fish species that could gain from stronger protection through the international framework.

Salmon, eels and lampreys are among the species due to be considered at the March 23-29 meeting in Campo Verde.

Most of the species identified occur in Asia, with South America and Europe following.

Priority river basins include South America’s Amazon and La Plata-Parana; Europe’s Danube; Asia’s Mekong and Ganges-Brahmaputra; and Africa’s Nile.

“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,” Zeb Hogan, the assessment’s lead author, said in a statement.

© Agence France-Presse