The Guardian reports:

Rivers in which fish populations have escaped serious damage from human activities make up just 14% of the world’s river basin area, according to the most comprehensive study to date.

Scientists found that the biodiversity of more than half of rivers had been profoundly affected, with big fish such as sturgeon replaced by invasive species such as catfish and Asian carp. Pollution, dams, overfishing, farm irrigation and rising temperatures due to the climate crisis are also to blame.

The worst-hit regions are western Europe and North America, where large and affluent populations mean humans’ impact on rivers is highest, such as with the Thames in the UK and the Mississippi in the US.

Rivers and lakes are vital ecosystems. They cover less than 1% of the planet’s surface, but their 17,000 fish species represent a quarter of all vertebrates, as well as providing food for many millions of people. Healthy rivers are also needed to supply clean water. [Continue reading…]