Management of the marine environment in Western Australia: An ecosystem approach

Abstract

The Environmental Protection Authority of Western Australia (EPAWA) has the responsibility of controlling industrial and domestic waste inputs to state waters. With continued industrial development and urban expansion to the north and south of Perth, pollutant loadings to nearshore marine environments will inevitably rise as a result of increases in industrial and domestic waste discharge, urban drainage and groundwater inflow. These increased loadings will inevitably cause additional stresses on the nearshore marine ecosystems of Perth. The EPAWA has adopted the concept of “assimilative capacity” as a philosophical approach to maintain the biological integrity of nearshore coastal ecosystems in Western Australia. This approach is based on the assumption that the receiving environment has some capacity, albeit limited, to disperse, dilute and absorb certain types of pollutants without incurring long-term damage to the biological functioning of the marine communities in question. This approach will be outlined using case studies. In the first case-study Cockburn Sound, a marine embayment adjacent to the southern metropolitan waters of Perth, will be used to explain how this approach can be used to ‘rehabilitate’ formerly severely polluted waters. In the second case-study the EPAWA's approach to controlling nutrient enrichment of the nearshore waters of the Perth region (which includes the Marmion Marine Park) will be used to demonstrate how the principle of the “assimilative capacity” approach is being utilised to prevent deterioration of “pristine” ecosystems.