The north west of Western Australia has productive commercial and recreational fisheries and extensive offshore oil and gas (O&G) infrastructure. These man-made structures support a range of demersal and pelagic fishes which are targeted by recreational and commercial fishers. As this O&G infrastructure reaches the end of its productive life, decisions on the best practice option for decommissioning must be made. The current policy for decommissioning requires complete removal. Regulators may support alternative strategies, such as leaving infrastructure in place, if risks and impacts are minimised and there are clear environmental, social and economic benefits to do so. It is thought that removal of infrastructure will decrease catch rates and have negative ecological, economic (direct and downstream) and social consequences.

At the same time as the discussion is occurring about removing O&G infrastructure, there have been large investments in constructing and installing purpose built man-made aquatic structures on the seafloor for the express purpose of enhancing the experience of recreational fishers and SCUBA divers.

There is a need to deliver critical information on: 1) the ecological, economic and social value of these man-made structures to recreational and commercial fishers and other stakeholders; 2) the attitudes of stakeholders to man-made structures; and 3) the opportunities and risks of decommissioning strategies to fishers and other groups (e.g. tourism).

Policy regarding the removal of decommissioned structures will benefit from the increased clarity that this project will provide in regards to data requirements for socio-economic models and stakeholder consultation methods. Comparative assessments of decommissioning options rely on the existence of appropriate socio-economic data, a knowledge gap this project aims to fill. An understanding of the impact of man-made aquatic structures on recreational and commercial fisheries is a global priority, and as such this project has strong international importance and relevance.

Knowledge of changing environmental conditions and productivity as a result of climate change is essential for adaptive management. In addition to direct applicability to fisheries and aquaculture in southern Tasmania, this information will have numerous important applications to other industries and stakeholders in the broader catchment.

CSIRO and TAFI have established a program (INFORMD- Inshore network for observation and regional management: Derwent-Huon) to guide multiple use coastal zone development and management. Storm Bay is an integral component of the INFORMD region and a priority is to understand both the short term (climate variability) and long-term (climate change) drivers of productivity in the region and link these to production of fisheries and aquaculture. CSIRO have a project investigating novel observing technologies (NOTe) to characterize the Derwent to shelf environment and TAFI will fund a charter vessel to monthly sample water column environmental variables, and support the CSIRO observing system. Thus an opportunity exists to obtain nutrient and productivity data in the Storm Bay region in a very cost-effective manner by collaborating with the existing research program.

Important background information is that the East Australian Current is predicted to penetrate further south causing significant warming and decreased productivity. Previous work (Harris et al 1991) showed that the nutrient status of waters clearly indicated the influence of the EAC, and primary producers indicated the productivity of the region, demonstrating the potential for Storm Bay to act as an indicator of productivity for Southern and Eastern Tasmania. Such information is important to understanding changes in fisheries and aquaculture production and, as a consequence, to assist with developing climate change adaptive management strategies.

This project also provides an opportunity for FRDC to invest in a project that will have significant influence on multiple use management in Australia.