Canton of Schaffhausen – Graylings in the Rhine suffer from heat stress – News

Some fish have already died. However, there should not be a mass death like in 2018 in Schaffhausen.

• Due to the high water temperatures, certain fish in the Rhine are struggling to survive.
• In the last few days fishermen have found isolated dead grayling and trout.
• However, large accumulations of dead fish in the Rhine, as in the hot summer of 2018, are not to be expected.

Water temperatures of sometimes over 27 degrees are currently affecting the grayling and trout in the Rhine. “There are very threatening temperatures,” says the Schaffhausen fisheries supervisor Patrick Wasem. Although cold water basins on the Rhine tributaries offer the animals refuge, individual fish did not survive the heat wave.

Patrick Wasem cannot yet estimate the extent of the damage. Only measurements in spring bring clarity. However, such a dramatic situation as in the hot summer of 2018 is not to be expected.

At that time there was a large fish kill in the Rhine. Several tons of grayling and trout died. Only ten percent of the grayling population survived. Since there are now significantly fewer graylings, there should not be such large accumulations of dead animals as in the past.

Legend:

In the hot summer of 2018: the Neuhausen fishing club had to fish numerous dead grayling and trout out of the Rhine.

Keystone/Melanie Duchene

If the population sees dead grayling or trout, they should not collect them. Fishermen take care of the animals and dispose of them. It is also important that swimmers avoid the cold water pools.

What is the situation in the neighboring cantons?

Like Schaffhausen, the canton of Thurgau also reports a few dead fish. According to the responsible hunting and fishing administration, the situation with regard to the water temperature is precarious. That’s what the Schaffhauser Nachrichten writes.

Canton of Zurich gives the all-clear

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Legend:

The graylings need cool water.

SFV Swiss Fishing Association/Rainer Kuehnis

So far, no fish kills have been observed in the canton of Zurich. As the Schaffhauser Nachrichten write, the fish use the cold water zone created near Rheinau.

Also in the canton of Aargau Fisheries organizations worried about heatwave. Because at the measuring station below the Beznau nuclear power plant, the Aare has been warmer than 25 degrees for a long time. If this is the case for three consecutive days, the nuclear power plant would have to shut down its two reactors. That is how it is regulated by law.

However, the Federal Office of Energy made an exception at the end of July. The reason for this is the energy supply. Without the electricity from the nuclear power plant, the tense situation would get even worse in winter. The operator Axpo can therefore continue to operate the nuclear power plant at a reduced rate. As a result, the Aare only warms up minimally – by a few tenths of a degree.