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Almost a Quarter of All Freshwater Fish Species Are in Peril, Thanks to Humans

Global analysis finds that development, overfishing, and pollution have made rivers dramatically different habitats than they were 200 years ago. 

Photographer: Jeff T. Green/Getty Images

The 18,000 types of fish living in rivers make up a quarter of all vertebrate species. After two centuries of industrial development, 23% of them are now threatened with extinction, according to new research published today in the journal Science

Individual rivers face different challenges, from overfishing in the Mekong River to increased damming along the Amazon, said Sébastien Brosse, a freshwater ecology professor at Paul Sabatier University in Toulouse, France. What this study does is quantify those challenges.