MARINE ENVIRONMENTS OF SOUTHEAST AUSTRALIA (GIPPSLAND SHELF AND BASS STRAIT) AND THE IMPACT OF OFFSHORE PETROLEUM-EXPLORATION AND PRODUCTION ACTIVITY

Marine environments of the Gippsland Shelf (Gippsland Basin) and Bass Strait (Bass Basin) are described and an exploratory (preliminary) ass essment of the potential effects of petroleum exploration and producti on activity are outlined. Exploration activity has been undertaken in both areas and inferred environmental impacts are typically short term . Production activities are restricted to the Gippsland Basin, have po tential for long-term impact, and are likely to result in trace levels of hydrocarbons being present within 1 km of the point(s) of discharg e of drilling waste or wastewater. The inferred impact of produced was tewater, which may contain up to a maximum of 30 ppm of produced hydro carbons, on waters of the Gippsland Shelf is presently being modeled a nd quantified. Results indicate that the background level of produced petroleum in waters of the Gippsland Shelf is less than in areas aroun d Sydney and Melbourne affected by urban runoff. Potential strategies for monitoring environmental quality on the Gippsland Shelf include a biologically based ''mussel watch'' program.