Invasive species are transported by maritime commerce. Vessels may be a significant pathway for the introduction or spread of invasive species through the discharge of ballast water containing invasive species or the transport of invasive species that have attached to the boat hulls. Species such as the Mediterranean white snailgypsy moths, or wood-boring insects attach or burrow into products or packaging on one side of the Pacific and disembark on the other-in Washington State.

Invasive species such as tunicates or zebra or quagga mussels also may be transported in commercial ships’ ballast water.

For more information, see the following Web sites: