DOI: 10.18195/issn.0312-3162.25(1).2008.001-044 Records of the Western Australian ;\Iuseum 25: 1 44 (2008), Introduced marine biota in Western Australian waters 2 2 John M. Huisman', Diana S. Jones , Fred E. Wells" and Timothy Burton I Western Australian Ilcrbarium, l)epartnwnt of Fnvironnwnt and Conservation, Locked Bag 11).1, Bentley Delivery Centre, Western Australia 6983, Australia, and School of Biological Sciences and Biotl'chnology, Murdoch University, Murdoch, Western Australia 6150, Australia, Department of Aquatic Zoology, vVestern Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 69R6, Australia, ' Western Australian Department of Fisheries, Level 3,I6R St Georges Terrace, Perth, Western Australia 6000, Australia, Abstract - 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, Twenty- six 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. INTRODUCTION result of these pest intrusions (Paesanti et al. 1991; The introduction of exotic species into the Blanchard 1995; Blanchard 1997; Wyatt et al. 2005), marine environment is a major threat to native Some introduced species can directly impact biodiversity and ecosystem health (Padilla et al. human health, for example by toxin accumulation 1996; l-lass and Jones 2000), Three primary vectors in shellfish due to toxic dinoflagellates for marine introductions are recognised via (Hallegraeff et ai, 1988), Consumption of ballast water discharge, hull fouling or deliberate contaminated shellfish may result in illness or introductions, such as through aquaculture death (CampbeIl1994; Waiters 1996), (Carlton 1985) (species can also be accidentally Western Australia (WA) has, thus far, remained introduced by being attached to deliberately relativelv free of marine pests, lom's (1992a) introduced organisms such as oysters), While most recorded 25 marine introductions into the State'"s introductions remain relatively passive and waters, over half (15) detected since the 1970s and apparently co-exist with native without most of those introduced shipping, either as detriment, many others have the ability to become fouling organisms or via ballast water. Furlani pests, dominating and excluding local species and (1996) also recorded 25 introduced marine species resulting in major shifts in ecosystem structure in Western Australia. In 1999, this number was (Brenchley and Carlton 1983; Crosholz and Ruiz increased to 30 (Hass and jones 1(99), Those 1995), Local loss of biodiversity is an inevitable introductions that have been reported have 2 J.M. Huisman, D.S. Jones, F.E. Wells, T. Burton generally remained innocuous, or have been largely a major pest in the Mediterranean (Verlaque et £11. restricted to artificial environments such as 2003). The vector by which these introductions harbours. This parallels the situation in other occurred is not known, especially in areas where Australian areas. A search of the National native fauna is not well documented. Introduced Marine Pest Information System website Several factors can hamper marine pest surveys. (NIMPIS 2002) reveals a list of 44 species Obvious impediments include the marine introduced or possibly introduced into WA. environment itself, as most introductions remain Additional information presented here increases the hidden from sight, their presence often only number of known introduced species to 60. As yet revealed by snorkelling or SCUBA diving. Perhaps there are no published data regarding adverse of greater significance, however, is the difficulty in impacts of introduced species in Western Australia accurately identifying introduced species and (Hass and Jones 1999), but several have been shown assessing their impact. For almost all introduced to have significant impacts in other areas, by species it is virtually impossible to ascertain the competition for food and/or space. For example, no 'event' that led to the introduction, and many are threats to Western Australian native species, not observed until they are well established and fisheries or seagrass beds were identified through essentially impossible to eradicate. Accurate the introduction of SabeJJa spaJJanzanii, the identification is essential, primarily to ensure that European fan worm (Clapin and Evans 1995), introduced species are not missed, but equally to although studies in Victoria have suggested that ensure that native species are not inadvertently this species has the potential to compete with native recorded as introductions, as there are many filter feeders and change the structure of the benthic undescribed native species. For example, some food web (WaIters 1996). Adverse impacts may not species generally considered to be cosmopolitan occur until decades after the initial introduction and may be undocumented introductions or, conversely, establishment (Courtney 1990) and it would, non-introduced native species (Chapman and therefore, be extremely short-sighted to assume that Carlton 1991; Poore 1996). Western Australia's relatively unaffected marine The large number of ships, private yachts, and environment is somehow immune to infestation by illegal foreign fishers means that there is a pest species. considerable current potential for additional marine While the impact of introduced species in WA is species to be introduced into WA. The current as yet unknown, the likelihood of a pest outbreak resource boom is concentrated in the Pilbara, but is high, as the State includes many high traffic includes all parts of Western Australia. The planned ports with a variety of habitats, ranging from increase in shipping movements means there will tropical to temperate. Even a cursory review of the be increased threats of species being introduced marine species known to be pests elsewhere will into WA. There have already been several incidents reveal that, for most, suitable conditions for their that give cause for alarm. In October 2002, the cutter growth and possible survival can be found suction dredge Leonardo da Vinci arrived in somewhere in the State (Department of Geraldton almost directly from the Caribbean and Agriculture, Fisheries and Forestry 2006). Thus the had a number of foreign species, including potential risk of a pest incursion is high and on-going pest species, in its sea chests or attached to its hull. vigilance is important if WA is to remain relatively Prompt action was taken by authorities to minimise pest free. It is also pertinent to point out here that the chances of an introduction. A resurvey is the incursion of marine pests is a two-way process. planned to see if any species have been introduced. For example, the Australasian barnacle A second incident occurred in late 2006, when the Austrominius modestus Darwin was introduced dredge Volvox Australia arrived at the port of into Europe from Australia or New Zealand Dampier fouled with the Asian green mussel, Pema following the end of World War II, attached to the viridis. It was denied entry and went to Singapore hulls of returning ships (Bishop, 1947). The species for cleaning in drydock before being allowed to spread, becoming established on the British return to WA. More recently a barge arrived in mainland coast and then extending to Europe Dampier and on inspection was found to have an (Bishop and Crisp 1957; Crisp 1958). Currently the extensively fouled hull. It was immediately ordered species occurs from the Shetland Islands to to go out to the 200 m depth contour and be cleaned Portugal and Maderia (Southward and Crisp 1963; before returning to port; on return to the coast the Hiscock et £11. 1978; O'Riordan and Ramsay 1999; ship was reinspected and allowed to enter Port Wirtz et al. 2006). Similarly the temperate Hedland. Australian gastropod Bedeva paivae (Crosse, 1864) In managing incidents such as these, it is critical has colonised South Africa (Kilburn and Rippey that we understand what species have been 1982) and the south-western