Environmental organisations have filed a complaint with the Council of Europe against the pollution of the River Doubs on Switzerland’s northwestern border with France.
The groups accused the authorities of failing to take action against polluters and the untimely release of water from power plants in the remote region.
“The Doubs dies and the king of the Doubs with it,” the groups warned on Tuesday.
The king of the Doubs is a protected fish species, Zingel asper, which is in danger of extinction.
The organisations said the use of fertilisers by farmers and water-level variation as a result of hydroelectric dams were possibly to blame for damage to the 450km long river. A 30km stretch of the Doubs marks the border in the Jura region between Switzerland and France.
In May up to a thousand people took part in a protest organised by the environmental groups in a village on the border with France.
swissinfo.ch and agencies