Fishing guide

Invasive quagga mussel could profoundly alter Swiss lakes – Expat Guide to Switzerland

The quagga mussel, originally from the Black Sea region, is spreading rapidly in Swiss lakes. Experts fear that invasive species will disrupt lake ecosystems.

The quagga mussel (Dreissena bugensis) was first discovered in 2014 in the Rhine near Basel. Since then, it has spread rapidly and has already colonized many lakes in Switzerland, namely Lake Constance, Lake Geneva, Lake Neuchâtel, Lake Biel, Lake Murten and Lake Hongrin ( near Lake Geneva), the Swiss Federal Institute of Aquatic Science and Technology (EAWAG) said in a statement Thursday.

Together with the zebra mussel, which has been spreading in Swiss lakes since the 1960s, the quagga mussel is one of the most aggressive invasive species.

The quagga mussel is able to breed almost year round and can inhabit soft substrate in deep water areas. These characteristics, along with the fact that it is more efficient at absorbing nutrients, are believed to be the main reasons why the quagga outperforms the zebra mussel in deep-water lakes, and why it increasingly crowds them out. said EAWAG.

Mussels spread either naturally by floating in the current as larvae and carried downstream, or by being carried unintentionally by humans in the ballast, bilge or cooling water of boat engines and ships. pleasure boats. Additionally, adult mussels stick firmly to boats and other objects, and if these are not cleaned or properly dried before being moved to different lakes, mussels can also spread in this manner.

“Profound Consequences”

“Based on observations we have from North America, we fear that the presence of the quagga mussel will have profound consequences for the ecosystems of our lakes, the balance of which could potentially be upset,” said Piet Spaak, researcher at EAWAG, responsible for the SeeWandel project, which involves seven research institutes in Germany, Austria and Switzerland. They study the complex interplay between nutrient depletion, climate change, invasive and non-native species, and other stressors.

Although the detailed consequences are still unknown, they could include a reduction in plankton, as mussels filter large volumes of phytoplankton, a reduction in fish stock due to an altered food web, mussel shells in coastal areas and increased maintenance and costs, for example for boats, pipes and fishing nets.

swissinfo.ch/ts