More than a third of freshwater fish are threatened with extinction, according to interim results from an IUCN Red List assessment.
The preliminary results, revealed by scientists at the annual conference of the Fisheries Society of the British Isles at Bournemouth University, suggest that along with amphibians, freshwater fish may now be considered one of the most threatened groups of species in the world.
Dr William Darwall, manager of the freshwater unit at the IUCN in Cambridge, says, “There are still some big gaps in our knowledge, but of the 5,685 species that have been assessed, 36 per cent of them are threatened.”
The European eel has declined by 90 percent since the early 1980s, while the Atlantic sturgeon, which is the source of one of the most expensive forms of caviar and was once common in rivers around Europe, is now only found in a single river in France, where it has an estimated population of between 20 and 750 individuals. The Mekong giant catfish may be down to just 250 individuals in the wild.
Many little-known fish which become isolated in remote waterways are also among those with the greatest risk of dying out.
Human activities blamed
Overfishing, pollution and development have been cited as the main reasons for declining freshwater fish populations.
The loss of these fish may also have serious implications for humans, with freshwater fish often providing a staple diet in many parts of the world. In Africa, for example, more than 7.5 million people rely on freshwater fish for food and income.
“Sadly, it is also not going to get any better as human need for fresh water, power and food continues to grow and we exploit freshwater environments for these resources,” says Dr Darwall.
A ‘crucial issue’
Professor Rudy Golzan, director of the Centre for Conservation Ecology at Bournemouth University, says, “Freshwater biodiversity is a crucial issue and more important than people think. Billions of people rely upon freshwater species for food and work.”
“We have to find ways of reducing impacts on these ecosystems while allowing people to continue to use the resources that freshwater environments have to offer.”
Visit the Fisheries Society of the British Isles website.
Read the article in the Telegraph.
Helen Roddis, ARKive Species Text Author