QMs were carried to the Untied States (US) in ship ballast tanks and were introduced to the Great Lakes region in 1989.

For nearly 20 years, QMs have spread across the US and have entered California waterways. In January 2007, QMs were discovered in Lake Mead and the Colorado River system. Recently QMs have been found in 20 South West lakes and water ways.

Quagga Mussels attached to a boat engine. QMs can live on aquatic plants and be transported to non-infested waters.

QMs are commonly spread by the following methods: