The quagga mussel continues to proliferate in Lake Geneva: how to avoid over-introduction and what impacts?
The quagga mussel has been expanding rapidly since 2015 in Lake Geneva. Its development should stabilize within 4 to 5 years. The CIPEL would like to remind the good practices to adopt to avoid an over-introduction and propagation towards other aquatic environments still preserved until now, in order to limit the impacts on the functioning of the ecosystem and the services provided by the lake (production of drinking water, fishing, thermal exploitation, leisure activities).
The quagga mussel is an invasive alien species originating from the Black Sea region. It arrived accidentally in Lake Geneva, due to the transfer of boats from one environment to another, and settled there. It quickly replaced the zebra mussel, another undesirable species present in Lake Geneva since the 1960s. A scientific follow-up is set up by the CIPEL to monitor the effects of the quagga mussel on the functioning of the lake.
How to avoid an over-introduction of the quagga mussel in Lake Geneva?
The quagga mussel attaches itself to boats, but also to water sports and fishing equipment. The CIPEL therefore recommends to clean efficiently boats and equipment moving from one lake to another, before any launch in Lake Geneva.
The essential gestures to adopt are the following:
- Clean the hull of the boats, empty the ballast water that may contain the larvae and run the engine on land for a few seconds before the transfer (Note: it is important to do these operations before the transfer begins)
- Clean all equipment that may have been submerged (life jackets, diving equipment, ropes, anchors, fenders, etc.)
Prevent the arrival of other invasive alien species
To avoid spreading new unwanted species, CIPEL also reminds aquarists to never dump animals, plants and aquarium wastewater into the environment.
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What impacts does the quagga mussel have on Lake Geneva and the services it provides?
As an adult, the quagga mussel finds its food by filtering up to 2 liters of water per day. The gigantic volumes of water thus filtered modify the distribution of resources available to other living organisms, thus upsetting the food chain.
The quagga mussel clings to many types of natural substrates, but it also colonizes metal pipes used to pump water from the lake for drinking water production and air conditioning to naturally cold water, as well as fishing gear, causing significant damage and costs.
In this context, CIPEL is attentive to the effectiveness and side effects of techniques to control the proliferation of the quagga mussel, particularly chemical-based control.
Towards a more effective fight in cooperation with the other managers of the large Alpine lakes
Faced with the magnitude of the problem that affects all aquatic environments, the CIPEL is in contact with other managers of large alpine lakes to share knowledge and solutions, and act more effectively.
For more information:
- Lake Bourget (France)
- Canton of Vaud
- Lake Annecy (communication to come)
Photograph of a scientific measuring instrument completely colonized by the quagga mussel after one year of immersion in the lake at the depth of 8 meters. Until now, these "shock" images always came from North America, as bio-fouling in Europe was always much less spectacular.
Credit: LéXPLORE, Sébastien Lavanchy