<
https://www.theguardian.com/environment/article/2024/may/21/living-planet-index-migratory-freshwater-fish-populations-decline-dams-weirs-mining-water-abstraction-pollution-threat-aoe>
"Migratory fish populations have crashed by more than 80% since 1970, new
findings show.
Populations are declining in all regions of the world, but it is happening
fastest in South America and the Caribbean, where abundance of these species
has dropped by 91% over the past 50 years.
This region has the world’s largest freshwater migrations, but dams, mining and
humans diverting water are destroying river ecosystems. In Europe, populations
of migratory freshwater fishes have fallen by 75%, according to the latest
update to the Living Planet Index.
Migratory freshwater fish partially or exclusively rely on freshwater systems –
some are born at sea and migrate back into fresh water, or vice versa. They can
in some cases swim the width of entire continents and then return to the stream
in which they were born.
They form the basis for the diets and livelihoods of millions of people
globally. Many rivers, however, are no longer flowing freely due to the
construction of dams and other barriers, which block species’ migrations. There
are an estimated 1.2m barriers across European rivers.
Other causes of decline include pollution from urban and industrial wastewater,
and runoff from roads and farming. Climate breakdown is also changing habitats
and the availability of freshwater. Unsustainable fishing is another threat.
Herman Wanningen, founder of the World Fish Migration Foundation, one of the
organisations involved in the study, said: “The catastrophic decline in
migratory fish populations is a deafening wake-up call for the world. We must
act now to save these keystone species and their rivers.
“Migratory fish are central to the cultures of many Indigenous peoples, nourish
millions of people across the globe, and sustain a vast web of species and
ecosystems. We cannot continue to let them slip silently away.”"
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
