Heat and drought strain fish as Carinthian waters shrink

Heat and extreme drought are drying up smaller streams and waterways in Carinthia, while warmer water is reducing oxygen levels and weakening fish, ORF reported. Lower spring flows and low water levels have left an estimated 10 to 20 percent of waters in Lower Carinthia dry or with very low flow.

The Rababach near Hörtendorf, close to Klagenfurt, has been reduced to a trickle. Fish and other aquatic life have retreated to deeper pools, where water ecology experts from the provincial government measured temperatures of 27 degrees Celsius.

“For these small waterways, the situation is already serious,” said Thomas Friedl of the provincial water ecology department. “The fish are under massive stress. The water flow is declining. Normally, the Rababach has an average low-water flow of 50 litres per second. We are now at a few litres per second.”

Downstream, the streambed has already dried out in places because no new springs are feeding the watercourse and the remaining water is seeping into the ground. Reports of fish deaths have not yet emerged, unlike in other Austrian provinces. The fish appear to be moving upstream or withdrawing into pools until water returns, Friedl said.

An emergency removal of fish from the pools has not yet been necessary. Owners of fishing areas have been instructed to monitor their waters.

The drought is also affecting fish farms. Markus Payr, chairman of the Association of Carinthian Fish Farmers, said his operation generally had a good supply of spring water but currently had three ponds without water or fish. Facilities supplied by streams are facing even greater pressure because less water is available and warmer water contains less oxygen.

Fish farms are using aerators to manage the problem, but continued water shortages could force the industry to change. Payr said there were fears that new facilities would hardly receive approval in the future.