Introduced marine biota in Western Australian waters

An annotated compendium is presented of 102 species of marine algae and animals that have been reported as introduced into Western Australian marine and estuarine waters, four of which arc on the Australian national list of targeted marine pest species, For each species the authority, distribution (both in Western Australia and elsewhere), voucher specimen(s) and remarks are given, Sixty species are considered to have been introduced through human activity, including three on the list of Australian declared marine pests, The most invasive groups are: bryozoans (15 species), crustaceans (13 species) and molluscs (9 species), Seven of these introduced species, including four natural introductions, have not been found recently and are not presently considered to be living in Western Australia, Twentysix species are regarded as cryptogenic or native, The records of nine species, including two declared marine pests, are questionable or rejected, The distribution of the 60 introduced species shows that most (37) arc temperate species that occur from Geraldton south; only 6 arc tropical species that occur from Shark Bay north; 17 introduced species occur in both the southern and northern halves of Western Australia, Because most of the introduced species are temperate species, southern marine areas have more introduced marine species than northern areas, The greatest concentration is in the southwest corner: 46 in Fremantle, Cockburn Sound and the lower Swan River; 25 in Albany and 24 in Bunbury, We conclude with a' strong recommel~dation that continuing baseline taxonomic research and survevs of the vVestern Australian marine waters be regarded as an essential comt;onent of protecting and managing the State's valuable marine environment.