Other examples of introduced species which occur in large numbers and are inferred to be having an impact on the native fauna are the the Asian Mussel Musculista senhousia (Crooks 1998), the European Clam Corbula gibba (Talman and Keough 2001) and the New Zealand Screw Shell Maoricolpus roseus.

Between about 1885 and 1930, an abortive attempt was made to deliberately introduce the New Zealand oyster (Tiostrea chilensis lutaria) to SE Tasmania. Probably through these shipments, a number of other species, including the New Zealand Screw Shell (Maoricolpus roseus), several other molluscs (Chiton glaucus, Neilo australis, Ruditapes largillierti), a starfish (Patiriella regularis) and a crab (Cancer novaezelandiae), were accidentally introduced (Dartnall 1969; Carlton 1992; Furlani 1996; R. Willan pers. comm.) and are now well established there. For instance, the New Zealand Screw Shell has now spread along the eastern continental shelf of Tasmania, where it is often the dominant element of the macrofauna, and has recently crossed Bass Strait. A few individuals have also recently been found in Sydney Harbour.

Of concern are species not yet present but likely to become serious invaders. There needs to be awareness of what the likely invaders are and their likely modes of entry. The characteristics of some species make them likely suspects as invasive species. For example, Chapman and Carlton (1991) predicted that the supposedly invasive Oriental Isopod (Synidotea laevidorsalis) was established in Brisbane, or Sydney, Australia. These authors later reported that their prediction was proved correct (Chapman and Carlton 1994) but Poore (1996) showed that this supposed species was actually a set of closely related taxa, two of which are found only in Australia.

Information sheets on several marine pest species, including the introduced algae, can be accessed via CRIMP’s website.