More than half of the native fish species in Switzerland are at risk of extinction or are already extinct, a new report showed Wednesday.
The study of around 70,000 fish in Switzerland’s lakes and rivers categorised the native species according to the International Union for Conservation of Nature’s criteria.
The Federal Office for the Environment (FOEN) said that of the 71 native fish in Swiss waters, 34 are threatened with extinction, and nine are no longer found within Switzerland.
Nine native species have had their national threat category raised, including the stone loach, the European eel and the European grayling. The list hadn’t been updated since 2007.
“The 2007 Red List already showed a precarious situation for fish,” said Franziska Schwarz, deputy director of FOEN. “This revised list, unfortunately, shows no reversal of the trend: overall, the number of threatened fish species continues to increase, thus contributing
to the degradation of fish biodiversity.”
Switzerland is famous for its big lakes like Lucerne, Geneva, Constance, Neuchatel and Maggiore and rivers like the Rhone, Rhine, and the Aare.
The report said that human activities like water pollution, habitat degradation, and hydroelectric power generation are the main threats to fish. The consequences of global warming are also a significant threat to fish.
Rising water temperatures can cause stress in fish and affect their growth, metabolism, and reproductive success. And warmer water holds less dissolved oxygen, which is essential for fish survival. This can lead to “dead zones” in waterways where the water is too warm and oxygen-deprived for fish to survive.
“Considerable efforts” to improve wastewater and stop heavy pollution and treatment have had a positive impact, the report said. Still, small rivers in intensive farming areas have a lot of micro-pollutants.
The nine fish species now considered extinct in Switzerland are the Atlantic salmon, the European sturgeon, the sea trout, the allis shad, the weatherfish, the huchen, the European river lamprey, the sea lamprey and the Salvelinus neocomensis deepwater trout.
