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Globally invasive marine species have been identified by the International Maritime Organisation (IMO) as one of the four greatest threats to the world's oceans because of their impacts on the environment, economy and public amenity. More than 250 introduced marine organisms have become established in Australian waters since European settlement, and the threat of new introductions is constant. As trade with other countries grows, so too does the risk that exotic marine organisms will be introduced through ballast water discharge and hull fouling. One of the most significant natural resource management issues facing Tasmania is the problem of introduced marine pests. Introduced marine pests threaten the State's bio-diversity, its marine industries, and the public amenity of the marine environment. Tasmania already has a significant marine pest problem with species such as the Northern Pacific seastar (Asterias amurensis), the Japanese kelp (Undaria pinnatifida), and the toxic dinoflagellate (Gymnodinium catentatum) to name just 3 of the 58 invaders in the State. Not all introduced marine species become pests, however, in Tasmania there are 10 introduced species that are recognised pests on the Australian ballast water target species list. Most non-native marine organisms in the State were probably introduced by international shipping. Ballast water discharge and hull fouling are thought to have been responsible for transporting 26% and 40% of introduced species into Tasmanian coastal waters respectively (Thresher et al. 1999). While no longer a high risk, historically, other vectors responsible for transporting non-native marine species to Tasmania have been dry ballast (10%), deliberate and accidental introductions associated with aquaculture (21%), and other intentional introductions (3%) (Thresher et al. 1999). Once established in Tasmanian coastal waters marine pests can easily spread to other areas in the State by commercial and recreational boating, coastal shipping, aquaculture activities and diving. Management of marine pests is complex because it requires cooperation from international shipping organisations, all levels of government, marine industries and the community. Despite the clear threat that marine pests pose, management of marine pests has been somewhat ad hoc in the past. To address this, the prevention and management of introduced marine pests in Australia was the focus of a National Taskforce report (SCC/SCFA 2000). The report was endorsed by three Ministerial councils (Australian and New Zealand Environment and Conservation Council ANZECC, Ministerial Council on Forestry, Fisheries and Aquaculture MCFFA, and the Australian Transport Council ATC) in 2000. The National taskforce report, available from the Environment Australia web site, made several recommendations on how to manage the threat of marine pests. One of the Taskforce recommendations was for staged implementation of port baseline surveys in all Australian first ports of call and a targeted approach to surveying other ports and marinas. To date our knowledge of the scale of the problem of introduced marine organisms has been seriously impeded by a lack of baseline data. Before the last SoE Report (SDAC 1997) baseline port surveys had only been performed at Devonport and Flinders Island in 1996. Little was known about the abundance and distribution of introduced marine species in other areas in the State.
Introduced marine pests impact on our marine environment threatening biodiversity, marine industry and the public amenity of our coasts. Because of a lack of baseline data, it is difficult to prove some impacts of marine pests. For example dense beds of the Japanese kelp (Undaria pinnatifida) probably cause a decreased abundance of native macro-algae by competing with them for space. However, without baseline data on the abundance and diversity of the native macro-algae before the pest was introduced there is no way of measuring this impact. Recent ecological studies have indicated that some marine pests exclude native species through increased competition and predation (e.g. Mackinnon 1997 and Ross 2001). Marine pests can also impact on the State's valuable aquaculture industry. For example, blooms of the introduced toxic dinoflagellate (Gymnodinium catenatum) can cause high levels of toxins to build up in commercial mussels and oysters causing temporary closures of marine farms. The presence of these organisms in State waters has necessitated monitoring of shellfish to ensure they are safe for human consumption before they are sold. Marine pests can also impact on commercial shipping. Domestic and international restrictions on ballast water exchange can be applied to vessels based on the marine pests present in the port where ballast water was taken up. Because of the marine pests present in Tasmania, authorities in Port Phillip Bay (Victoria) and New Zealand have declared that ballast water from Tasmanian ports is too high a risk to accept. These ports do not allow ships to discharge ballast water originating from Tasmania in their waters. The Northern Pacific seastar (Asterias amurensis), probably the worst introduced marine pest in the State, was introduced into the Derwent River in the early 1980s. The seastar is a voracious predator and can eat a wide variety of prey including other echinoderms, ascidians, polychaetes, and crustaceans, although it prefers bivalve molluscs. It is a serious pest to the State's shellfish farms because the young seastars can settle into spat collectors and eat stock. Asterias amurensis also threatens biodiversity by competing with native species and preying on benthic invertebrates, and it may be responsible for the decline of the endangered spotted handfish, which is endemic to the Derwent River. While some species such as the European green crab (Carcinus maenas) and the European clam (Corbula gibba) are distributed throughout a large area of the State, populations of many introduced marine pests are restricted to specific regions within the State. For example the Northern Pacific seastar (Asterias amurensis) and the Japanese kelp (Undaria pinnatifida) have only established populations on the east coast of the State, while the European fanworm (Sabella spallanzanii), and the Asian bag mussel (Musculista senhousia) are restricted to the north coast. An important step in mitigating the impact of marine pests is to prevent their spread to new areas (translocation). There are still serious gaps in our knowledge of the distribution of marine pests in the State. The full extent of marine invasions in Tasmania will not be known until baseline surveys have been completed. In particular there is little information on the distribution and abundance of introduce marine species in more remote areas of the State such as King Island, the west coast and Macquarie Island.
Assessing and measuring the current situation The Centre for Research on Introduced Marine Pests (CRIMP) has developed protocols for baseline port surveys for introduced species (Hewitt and Martin 2001). These surveys consist of qualitative and quantitative sampling of ports and the surrounding coastal waters for introduced and cryptogenic (i.e. uncertain invasion status) species. The survey design includes benthic cores, pylon scrapings, plankton and neckton tows, video and photo transects, visual surveys, crab and shrimp traps, and monitoring for toxic dinoflagellate cysts. This combination of survey techniques ensures that all types of marine pests are targeted in the survey design. In addition to collecting biological information, environmental data are also collected (temperature, salinity, turbidity and particle size analysis) and there is a public awareness program during the port survey. These baseline surveys are extremely expensive and take a long time to complete because of the large amount of fieldwork required, and the need for all species collected in the field to be identified by expert taxonomists. The DPIWE have recently received a National Heritage Trust Strategic Package grant to help complete the port baseline surveys of all first ports of call and other high risk ports/marinas in Tasmania. As baseline surveys of each major port and other high risk areas in the State are completed there will be more records of introduced species. This is not necessarily an indication that the invasion rate is increasing. The species may have remained undetected for several years in our coastal waters. Baseline surveys will determine how many marine pests have been introduced since European settlement. Monitoring after the baseline survey will give an indication of how many new species are invading, and whether steps taken to prevent new introductions are effective. The Australian Quarantine and Inspection Service (AQIS) has developed a Decision Support System (DSS) to assess the risk posed by ballast water from individual ships. The DSS is a component of Australia's mandatory ballast water management requirements, which were introduced in 2001. Under these requirements a vessel must exchange ballast at sea (or use an equivalent on board treatment) or use the DSS to provide an appropriate ballast water management option. The Decision Support System provides ballast water management options based on the risk posed by the ballast water, 'low risk' ballast water can be discharged in ports, while 'high risk' ballast water can not. Ballast water from a port that has large numbers of marine pests is considered high risk. If a port has not had a baseline survey it is automatically assigned the highest risk ranking under the DSS. The information collected from the port baseline surveys will be fed into the DSS. The impact of introduced marine pests in Tasmanian coastal waters
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Major actions taken since the last SoE Report (SDAC 1997) relevant to the management of introduced marine pests in Tasmania include the following: In the past management of introduced marine pests in Tasmania has been impeded by an uncoordinated approach at a National level and a lack of baseline data. Since the last SoE Report (SDAC 1997) there has been a National Taskforce report which addressed the issue of introduced marine pests in Australia (SCC/SCFA 2000). This report, which was endorsed by three ministerial councils, makes recommendations for prevention and management of introduced marine pests. This has lead to a more coordinated approach to the problem nationally. In 1991 mandatory ballast water regulations were introduced by the Australian Quarantine and Inspection Service (AQIS) whereby the majority of international vessels exchange their ballast en route to Australia. This reduces the risk that marine pests will be introduced to Tasmania via ballast water discharge. Funding from a Natural Heritage Trust Strategic Package grant to determine the current distribution of introduced marine organisms in the State through surveys of ports and other high risk areas has resulted in baseline surveys of the Ports of Launceston and Hobart in the last year. Baseline surveys of the remaining first ports of call and other high risk areas in the State are currently being organised. These represent major improvements to introduced marine pest management in the State over the last five years. However there is still a lot of work that needs to be done. For example, the data collected during baseline surveys will not remain current without ongoing monitoring so port specific plans should be developed to ensure that the currency of the baseline data is maintained. Key directions for management of marine pests include the following:
Tasmania Together and the RMPS Relevant Tasmania Together goals and standards for 'Coastal, Estuarine and Marine' are listed in the linked file. The Tasmania Together Progress Board reported on progress toward targets for benchmarks set (Tasmania Together Progress Board 2003). Indicators, targets and baseline data are available in the latest Progress Report June 2003. Further information, including progress report updates, is available from Tasmania Together. Involvement of the community, and the fair and orderly use of resources are also fundamental principles of the RMPS. The RMPS objectives have been developed to advance the principles of sustainable development.
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