14 Aug 2018
When water temperatures reach between 23 and 25 degrees Celsius, fish are in a critical situation. A week ago, the temperature reached 27.6 degrees in parts of the Rhine river, resulting in widespread concerns.
According to officials, a tonne of fish has already died in the Rhine in the canton of Schaffhausen.
"In the canton of Zurich alone, we've had to fish out and relocate the animals from 150 creeks across several hundred kilometres of watercourses,” said Eva Baier, water protection expert at the Swiss Fishing Federation. With the heatwave said to be around a while longer, what is done to help safeguard fish?
Baier and her team make use of several techniques. "In smaller waters, the animals are fished out using electric-fanned equipment and moved into surrounding cooler waters or, in emergency cases, to fish farms," says Baier.
Nets using electric charge are used. These attract the fish, but also cause them significant stress, making this option a lesser used one and only ideal for extreme cases.
Cooling the water temperature artificially is a preferred option. "In some stretches the water is aired so that enough oxygen is present," Baier told The Local.
"In other cases, cool water zones are created in which cooler streams are dredged and groundwater springs are placed under protection.”
There are approximately 70 species of fish in Switzerland’s waters, 54 of which are indigenous. Salmonids such as trout and grayling suffer the most under intense heat. Rescuing the fish is no easy task, especially seeing as larger rivers offer less protection – such as shading or deadwood accumulations.
The Swiss government has had to implement several measures to deal with the heatwave, such as airlifting water to cows in remote pastures. Switzerland is not the only country affected by summer’s intense heat, however. From Sweden’s Kebnekaise mountain no longer being the country’s highest point due to melting, to there being fear of a brussel sprout shortage across European farms – Soaring temperatures in Europe have prompted authorities to take action and work to save the environment.