The quagga mussel continues to proliferate in Lake Geneva: how can over-introduction be avoided and what are the impacts?
The quagga mussel has been expanding rapidly since 2015 in Lake Geneva. Its development should stabilise within 4 to 5 years. The CIPEL would like to remind you of the good practices to adopt to avoid over-introduction and propagation towards other aquatic environments which have been 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 can we 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 that boats and equipment moving from one lake to another be cleaned effectively before being launched in Lake Geneva.
The essential actions to adopt are the following:
- Clean the hulls of the boats, empty the ballast water that may contain the larvae and run the engine ashore for a few seconds before the transfer (Note: it is important to do this before the transfer starts)
- Clean all equipment that may have been submerged (life jackets, diving equipment, ropes, anchors, fenders, etc.)
Preventing the arrival of other invasive alien species
To avoid spreading new unwanted species, CIPEL also reminds aquarists never to dump animals, plants and aquarium waste water 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 litres of water per day. The huge volumes of water filtered in this way change the distribution of resources available to other living organisms, thereby disrupting the food chain.
The quagga mussel clings to many types of natural substrates, but it also colonises metal pipes used to pump water from the lake for drinking water production and air conditioning with 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 consultation 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 the other managers of the large Alpine lakes to share knowledge and solutions, and to act more effectively.
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Photograph of a scientific measuring instrument fully colonised by quagga mussels after a year of immersion in the lake at a depth of 8 metres. Until now, these 'shock' images have always come from North America, as biofouling in Europe has always been much less spectacular.
Credit: LéXPLORE, Sébastien Lavanchy