摘要：One-hundred-and-twelve alien species are recorded for marine, brackish and freshwater environments in Ireland, of these sixty-eight are thought to be established. Their arrival has been mainly due to shipping, aquaculture and the ornamental industries. There are almost thirty species considered to be invasive and some that have arrived recently may have significant future impact. The majority of recorded alien species will have arrived since 1950. Usually these species appear in Britain or Northern Europe before occurring in Ireland. The majority of the marine species will have originated from the North Pacific Ocean whilst most of the freshwater species will have originally been sourced from North America. The sixty-four cryptogenic species arise out of the uncertainty of their origin or as to how they will have arrived. Ireland being a recently deglaciated island and separated from the continental land mass will have acquired the majority of its biota since the last glacial retreat making distinction between native and alien species more difficult.
关键词：Ireland;Celtic Sea;aquatic species;introductions;alien;freshwater;marine;invasive;population status
