Is vessel hull fouling an invasion threat to the Great Lakes?

The introduction of species to habitats to which they are nonindigenous is a principal form of global change (Lawler et al., 2006). Introduction of non-indigenous species (NIS) has increased in both terrestrial and aquatic environments worldwide commensurate with increased global trade and travel (see Ruiz & Carlton, 2003). Human populations are utterly dependent on ships for global commerce, with over 40% of the world’s imports transported by sea by a fleet of more than 50,000 ships (Lloyd’s Register Fairplay, 2008; World Trade Organization, 2008). Not surprisingly, shipping has played a key role in the spread of NIS globally and is a dominant mechanism by which marine species have been introduced to a number of coastal habitats (Molnar et al., 2008). Shipping activities present a number of diverse vectors, by which NIS may be transported including ballast water, ballast sediment and fouling of the sea-chest and of numerous Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada N9B 3P4