Large Dams Threaten a Third of World’s Freshwater Fish
One third of the world’s freshwater fish are at risk if dozens of large hydroelectric dams are built in the Amazon, Congo and Mekong basins, aquatic ecologists have warned.
Very few dams have so far been built in the basins of the world’s three great tropical rivers because of their remoteness and vast catchment areas. But rising demand for clean electricity in burgeoning tropical cities, and new roads to areas once considered impossible to access, has led to plans for over 450 dams for the three mega-diverse river basins.
If the dams are built, tropical freshwater biodiversity, which is at its most diverse in the three river basins, could be devastated, say the authors.
“Large dams invariably reduce fish diversity and block movements that enable migratory species to complete their life cycles. This may be particularly devastating to tropical river fisheries where many species migrate hundreds of kilometres,” said the team of 39 American, Brazilian and European authors in the journal Science.
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