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Populations of migratory river fish around the world have plunged by a “catastrophic” 76% since 1970, an analysis has found.
The fall was even greater in Europe at 93%, and for some groups of fish, with sturgeon and eel populations both down by more than 90%.
Species such as salmon, trout and giant catfish are vital not just to the rivers and lakes in which they breed or feed but to entire ecosystems. By swimming upstream, they transport nutrients from the oceans and provide food for many land animals, including bears, wolves and birds of prey.
The migratory fish are also critical for the food security and livelihoods of millions of people around the world, while recreational fishing is worth billions of dollars a year. The causes of the decline are the hundreds of thousands of dams around the world, overfishing, the climate crisis and water pollution. |
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The scientists said the situation may be even bleaker than it seemed, as many declines began before 1970. Populations of sturgeon in the Great Lakes of North America, for example, have dropped by 95% from historic levels. Furthermore, suitable data has not been gathered on species in some of the world’s most biodiverse rivers such as the Mekong, Congo, Amazon and Yangtze, where researchers fear there will be hundreds of fish extinctions in the coming decades. |
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