ABSTRACT
Every single day thousands of marine species are transported by human activities around the Earth, far away from their native location to new areas where they become non-indigenous species (NIS). However, whether this introduced species will be successful in its new host habitat is a dynamic, very complex process entailing several transitional stages (Williamson 2006). During the process of invasion, NIS must overcome several ecological barriers at different stages of invasion before they are able to inflict ecological or economic harm. Colautti and MacIssac (2004) suggested a well defi ned framework linking the invasion process with different fi lters that have to be overcome to achieve subsequent stages. Throughout this chapter, an overview of the stages involved in the process of invasion of marine macroalgae will be presented, followed by a set of management
strategies that ought to be implemented at international level. Also some very remarkable European invasion case studies are described in detail to illustrate some of the processes and patterns described earlier in the chapter.
