The economic and environmental impacts of introduced marine pests (IMPs) can be sizable. They compete with native species, introduce diseases, damage fisheries and aquaculture, and exacerbate fouling.
An extreme example is in the Baltic Sea where the proliferation of an introduced jelly caused a systemic collapse of fisheries in the region, worth an estimated US$500 million/year. This pest is now present in the Caspian and Black seas.

Locally, pearling industry representatives have concerns regarding outbreaks of Black Striped Mussels given its significant potential impacts and the cost of remediation in Northern Australia during 1998. Darwin was a poignant reminder of the potential speed and scale of pest invasions and the problems they cause. The Pacific Seastar is another significant IMP in Australia, which has potential to impact commercial shellfish stocks and aquaculture.

A national framework for the monitoring of IMPs, has been developed by the National Introduced Marine Pests Coordination Group (NIMPCG) and the Commonwealth Department of Agriculture, Forestry and Fisheries (DAFF), identifying 55 species and 18 locations throughout Australia as high risk. Currently the knowledge in W.A. is fragmented and our capacity to address this threat is underdeveloped despite the fact that three of the top ten high-risk locations are Fremantle (2nd), Dampier (6th) and Port Headland (9th) and that monitoring implementation is imminent.

To undertake effective monitoring for these high risk pests at selected locations, researchers need to be skilled in discriminating native from introduced species. Furthermore, it is important that techniques used by marine pest laboratories are as nationally standardised as possible. To this end there is a need for W.A. researchers to visit other labs in Australia and New Zealand to make sure that there is consistent methods among comparable labs. This knowledge will allow local researchers to effectively monitor IMPs and develop national consistency.

The management plan for the Houtman Abrolhos; system (Anon. 1998, section 10) identified a number of objectives. In essence these relate to understanding human-use impacts on the marine environment of the Abrolhos Islands and the evaluation of the effectiveness of present and future management strategies to ensure ecologically sustainable multiple use of Western Australia's first Fish Habitat Protection Area. Also it is important to recognise the more general responsibilities that the state of Western Australia will likely have with respect to the Commonwealth under its Oceans Policy statement and to the ongoing environmental stewardship considerations that the conferring of accreditation by the Marine Stewardship Council on the western rock lobster fishery entails.

Specifically, within the context of the Abrolhos Islands management plan there is a need to quantify the physical impacts of current human activity on Abrolhos marine habitats and subsequently establish a monitoring programme central to the ecologically sustainable management of this unique area. However, in order to determine such impacts and monitoring schemes, a number of preliminary steps need to be taken.

1) There is a need to collate, from diverse sources, existing research information relating to the ecology of the Abrolhos Islands, the effects of natural perturbations and to gather information on the types and effects of previous human use on Abrolhos marine habitats where it is documented. This synthesis of information will perform two functions: the first will be a statement of the current status of environmental impact research at the Abrolhos and the second will be as a background document for use in current deliberations and decision making by the Abrolhos Islands Management Advisory Committee.

2) A small amount of survey (field) work is required to establish precisely the timing and locations where commercial (potting, trawling, handlining, aquaculture) and recreational fishing and diving occurs particularly in relation to environmentally sensitive areas of the Abrolhos This information is not available from existing reporting systems such as log books etc. In addition some survey work is necessary to determine and provide general descriptions/ground truth of the various habitat/community types. The results from this field work will facilitate discussion on the scope of the issues to be assessed and methods to be used in long term monitoring programmes.

3) A workshop of community representatives and technical experts (representatives from AIMS, the universities, etc.) is needed to allow the formulation of a dedicated research/monitoring programme that will take into account issues raised by all stakeholders, and the legislated requirements of state and federal governments in relation to ecologically sustainable management.