Fish in the Rhine: Will the grayling survive?

In Schaffhausen, “only a few” fish are dying in the heat these days. Also because most of them died earlier.

In the hot summer of 2018, over 90 percent of the grayling died in the Rhine.

Rainer Kuehnis / SFV

If the fish in the Rhine get too warm, they don’t die, they “die”. This is how Helmut Hubacher, the former SP President, put it in a column in August 2018, and he asked: “So is that climate change?”

Four years later, the fishing warden Patrick Wasem stands at the Rhine Falls in Schaffhausen and counts the years when fish died. 2013: the first great death. 2015: barely missed. 2018: huge fish kill. “And now, four years later, pretty much to the day, we’re back here,” says Wasem. A local journalist who knows him will later say: “It’s also emotional for him.”

This Friday, the people of Schaffhausen provide information about the situation of the fish in the Rhine. The fishing association warned on Wednesday that a fish kill was “imminent”. And when the trout and grayling die, experience has shown that it is here, at the Rhine Falls. Mass deaths in postcard Switzerland.

The border crossing

The Schaffhauser Wasem disputes the media information together with the fisheries supervisor from Zurich, “because the Rhine, you know, crosses borders”. Just like the problem, the climate, the weather, whatever you want to call it. The fish are dying regardless of the vocabulary.

The grayling lives in cold water, from a water temperature of 22 degrees it suffers, from 27 degrees it suffocates. The fisheries control center around Wasem has now created cold water basins for the fish in the Rhine and set up “recreation zones” in places where cold water flows. She has put up the fish awning, the journalists can see it this morning.

Wasem urges you to behave decently when viewing. Keep distance. Proceed in an orderly manner. “It just requires discipline now.” The fish in the Rhine are stressed. And the fishery supervisor Wasem also seems emotionally stressed, at least moved. He has done a lot for the fish, but he is powerless against the water temperature.

Grayling in a recreation area on the Rhine, taken on Friday, August 5, 2022, in Neuhausen am Rheinfall.

Grayling in a recreation area on the Rhine, taken on Friday, August 5, 2022, in Neuhausen am Rheinfall.

Michael Buholzer / Keystone

Since the beginning of the summer heat, “very menacing temperatures” have been registered at its measuring points, thirteen times over 26 degrees. Wasem reports “isolated losses” among the fish in the Rhine, but he emphasizes: “It’s not about a mass extinction like in 2018.”

The water temperatures are even lower than in the summer of 2018, when 28 degrees were measured. The fisheries control also reacted early: at the beginning of July everything was “in the pipeline”, as Wasem reports. However, the main reason why grayling are only dying “sporadically” today, and not by the ton like four years ago, is different.

Wasem says: Whether you have to pull out “tons” or not depends largely on the stock, and the great death of 2018 has “drastically reduced” the stock. Over 90 percent of the graylings died back then. So there are fewer dead grayling this year because there are fewer grayling that could die.

Maybe that’s climate change. Even more than what worried Helmut Hubacher in 2018.

The new normal

A recreation zone for the fish is located below the fisheries at the Rhine Falls. It is cordoned off in red and white, and a few grayling shimmer under the awning. Fifty meters further ahead, two stand-up paddlers splash in, the zone is also directly on a hiking trail. When asked about this, Wasem throws up his hands. “We can’t monitor the fish 24 hours a day.”

The fisheries control has been saving fish on all fronts since the beginning of the hot summer. “Kilometers” of streams are dry in Schaffhausen, says Wasem. They were fished out and resettled, a measure that could hardly save the grayling in the Rhine, nor other cold-loving species such as barbel or trout. The fish are already so stressed by the heat that they would hardly survive being fished out.

Fisherman Wasem can only hope that the water temperature will drop. The SRF Meteo forecast predicts cooling for the coming week, especially at night. Wasem says: “We assume that the situation will relax rather than worsen.”

Until then, the grayling will try to survive under their awnings. Some will die, many are gone. “I’m experiencing this situation – you know that – not for the first time,” Wasem said to journalists earlier in the morning. Later he would talk about the “now annual business” with the overheated fish, and again and again “from experience”.

The Schaffhausen fisheries control has adapted and got used to the new normal a bit. Helmut Hubacher’s question from 2018 as to whether that was climate change: today it only reads rhetorically.

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