Canton of Schaffhausen – Occasionally fish are dying in the Rhine – News

  • The high water temperatures in the Rhine have steadily increased the pressure on fish stocks in recent weeks.
  • In the last few days, a few dead fish have washed ashore in the canton of Schaffhausen.
  • However, large accumulations of dead grayling 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 grayling and trout in the Rhine in particular. As the canton of Schaffhausen writes in a statement, cold water basins provide some relief. Nevertheless, individual fish did not survive the heat wave.

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

This year, however, it should not be as dramatic as the situation in 2018. At that time there was a large fish kill in the Rhine. Five tons of fish, mainly grayling and trout, died. Only ten percent of the grayling population survived.

Why does the heat affect the fish?


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Fish need cool, oxygen-rich water. If the temperatures are too warm, the water does not dissolve enough oxygen. Even at 20 degrees, the grayling and trout suffer from heat stress. Above 25 degrees it becomes critical for the fish. Their organs can fail at the high temperatures.

Since the grayling stock is now drastically smaller, large accumulations of dead fish should not be expected this year, the canton states. The dead fish are collected and disposed of by fishermen. The population is asked not to collect the animals themselves.

What is the situation in other neighboring cantons?


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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.
  • In the canton of Thurgau, on the other hand, a few dead fish washed ashore. According to the Hunting and Fisheries Administration, the situation is precarious.

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