Human-mediated marine bioinvasions have altered the way we view the marine environment – virtually all regions of the global oceans have experienced the introduction of marine species (e.g., Carlton 1979; Coles et al. 1999; Cranfield et al. 1998; Cohen and Carlton 1998; Hewitt et al. 1999, 2004; Orensanz et al. 2002; Leppäkoski et al. 2002; Lewis et al. 2003; Castilla et al. 2005; Wolff 2005; Gollasch and Nehring 2006; Minchin 2006), placing marine and coastal resources under increased threat. Humans have almost certainly transported marine species since early attempts to voyage by sea. These ancient transport vectors were slow, and for the most part restricted to small spatial scales. The beginning of significant exploration and subsequent expansion by Europeans (post 1500 AD) has resulted in the transport of many thousands of species across all world oceans (Crosby 1986; di Castri 1989; Carlton 2001).