NEW INVASIVE SPECIES discovered in Vättern

Earlier this year, Dikerogammarus villosus, also known as the killer shrimp, was discovered in Vättern. This is a species never previously found in Scandinavia.

The killer shrimp is an invasive species that has caused major problems throughout Europe. When it invades a water, the ecology often changes and several of the native species decline markedly or even disappear altogether.

"The probability that the shrimp will spread through large parts of Vättern within a few years is unfortunately very high," says Ulf Bjelke, limnologist at SLU Artdatabanken. Sadly, it is considered impossible to eradicate this invasive species. However, the discovery does give us the opportunity to prevent the spread from Vättern to other waters, but also the spread of other invasive species to Vättern. Because it’s people who are primarily spreading this type of species –and we can all help to do something about it.

Help us prevent the spread!

• CLEAN all boats and equipment of plants, animals and mud before taking them to a new water.

• DRAIN all the water from your boat or equipment before moving it.

• DRY equipment such as diving suits, swimming gear, fishing equipment, boats and so on before moving them to a new water. It’s sufficient for them to air dry for just a few days.

Species found thanks to environmental monitoring

"Vättern's rich and diverse nearshoe zone is a valuable habitat with many rare species. That is why we regularly monitor aquatic insects, crustaceans and molluscs from here," says Friederike Ermold, water expert at the Lake Vättern Society of Water Conservation and coordinator for the environmental monitoring programme for Vättern.

It was during one such routine survey that the invasive species was found at three sites on the east side of Vättern.

"The discovery is a good example of the importance of environmental monitoring for the early detection of alien species," says Friederike Ermold.

facts about invasive alien species:

An alien species is a species that humans have spread, deliberately or not, to areas where they have not previously existed. Such species then establish themselves outside their natural range. Not all alien species cause concern, but some can cause major problems for biodiversity and the local environment and these are then called invasive.