الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 122 |  |  |
| | | from | 122 | | |
Abstract
A number of definitions have been applied to describe the term alien species; in many of them the term alien is a species, a sub-species or a lower taxon occurring outside of its natural range, or associated with established species.They are factors of change and threat native biological diversity (IUCN, 2002), or with species that threaten the diversity or abundance of native species, the ecological stability of invaded ecosystems, economic activities dependent on these ecosystems and/or human health (EPA, 2001).The significance of alien species in marine ecosystems worldwide has been highlighted in recent years from ecological, environmental and economic points of view (Wilcove et al.1998, Davis et al 2001, Streftaris et al. 2005). International organisations (UNEP/MAP/RAC/SPA, FAO/ DIAS, IUCN, ICES, IMO, CIESM) and the scientific community have addressed the issue through articles, review papers, databases and directories.