How Did They Get Here? Eurasian Mussel Transport to and Within the United States

Zebra and quagga mussels were transported to the great lakes via ships ballast water. Because ships are becoming larger and faster, and trade is increasing, organisms that live in the water column, like Eurasian mussel larvae (veligers), can be drawn into ballast tanks when ships take on ballast and transported alive across vast distances.

Click thumbnails for larger images: :

Ship discharging ballast water

Since their introduction to the U.S. zebra and quagga mussels have been transported by recreational boats and passive downstream movement of veligers in rivers. Adult mussels can survive out of water for up to 30 days (depending on the weather), so the mussels can easily survive a cross country journey in many cases. This website provides a calculator of recommended "drying times" for boats used in infested water based on temperature and humidity zones. The maps below show the rapid dispersal of zebra mussels in the U.S. between 1998 and 2004. Real-time maps (updated daily) with current distribution of quagga and zebra mussels can be found here (scroll down to "real-time maps").

Locations on boat and trailer where mussels and veligers may be found