Millions in damage feared: Invasive quagga mussel clogs pipes on Lake Constance

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Quagga mussels in a fishing net on Lake Constance

Photo: Felix Kästle / dpa

The waterworks on Lake Constance are fighting against an invasive mussel species that is spreading rapidly. The quagga mussel, which is up to four centimeters long, is not a problem for drinking water quality, but it gets stuck in pipes and filter systems, explained a spokeswoman for the Lake Constance water supply. The water suppliers around Lake Constance now want to take action against this with special filters, larger pipes and new cleaning methods. The quagga mussel was introduced from the Black Sea region around ten years ago.

According to a study by the University of Konstanz, the shellfish could cause millions of dollars in damage. They have also already arrived at Lake Geneva and Lake Biel. Lake Zurich, on the other hand, is still free of it. Flyers inform boat owners around Zurich to clean their boats before using them to avoid bringing in the mussel. According to one of the study authors, it is not possible to prevent the animals from spreading further in areas that are already infested.

Lake Michigan: 90 percent of the biomass

According to the study, the quagga mussel mass per square meter in Lake Constance, Lake Geneva and Lake Biel is expected to increase nine to twenty-fold over the next two decades, caused primarily by greater population in the deeper areas of the lakes. This could lead to major changes in the ecosystem.

The Lake Constance water supply estimates that Lake Constance is about 15 years away from the situation at Lake Michigan in the US. The mussel has spread so much there that it now represents around 90 percent of the biomass.

According to the study, possible consequences for the ecosystem include a decline in plankton and changes in fish populations. For some fish species, the food supply is increasing because they eat the mussel, while other stocks have declined due to the lack of plankton. The researchers write that the water in the lake would generally become clearer because there would be less plankton.

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