The introduction, establishment, dispersal and impact of introduced non‐native fishes

During the last 100 years, the propensity to translocate and introduce fish species, both intentionally and by accident, has increased dramatically, threatening virtually all forms of aquatic environment. An understanding of the factors associated with species introductions, their success or failure to establish, the rates and means of dispersal, and the potential and realized impacts is essential to the development of risk and impact assessment protocols, which are important decision-making tools for both national and inter-governmental organizations. This will help to improve our management capabilities to identify mitigation measures with an aim to control better fish introductions than is presently attempted by internationally agreed (voluntary) Codes of Practice and by existing conventional national regulations. As a contribution to this important, expanding area of ichthyology, this dedicated issue of the Journal of Applied Ichthyology presents selected papers from the Alien Fish sessions of the 11th European Congress of Ichthyology, which was held in Tallinn, Estonia, on 6–10 September 2004. The aim of these sessions was to provide a forum for marine and freshwater ichthyologists to compare and contrast methodologies associated with the four phases of invasion biology (introduction, establishment, dispersal, impact) so as to facilitate cross-pollination of conceptual and applied approaches.