Western Australia has 27,000 km of coastline extending from the Great Australian Bight to the Timor Sea. The climatic setting grades from temperate on the south and lower west coast, through tropical semi-arid on the northwest coast to monsoonal in the north. Tides range from less than 1 m in the south to over 10 m in the north. Coastal waters on the south and west coast are generally nutrient poor and very clear whereas inshore waters along the northwest and northern coast contain higher suspended sediment loads and are more turbid. The Leeuwin Current flows southward in winter, maintaining relatively high seawater temperatures and providing a mechanism to transport tropical species into temperate waters.
This physical setting has produced a wide variety of ecosystem types with many unique features. These include: extensive arid-zone mangrove communities along the Pilbara coast; a 270 km long fringing coral reef less than six km offshore (Ningaloo Reef); an inverse-estuarine ecosystem maintained by 20,000 km2 of seagrass meadows (Shark Bay); an extensive high latitude coral reef complex (Abrolhos Islands); and nutrient-poor coastal embayments protected by limestone reefs and characterised by highly diverse and endemic seagrass flora (central west and south coasts).
As a result, Western Australia has an exceptionally rich marine biodiversity that is ranked second in the world in terms of its endemism. The many unique features of Western Australia's marine environment pose challenges to managers because traditional management methods developed for east-coast or overseas ecosystems are often not appropriate for our conditions. To be effective, management must be underpinned by a sound understanding of the effects of human induced pressures on the structure of these local systems and on the key ecological processes that sustain them.
Urban and industrial development in WA generally has a coastal focus and shipping ports are associated with most of these coastal developments. In between these nodes our coastline is largely undeveloped and in a relatively pristine state. Some areas are developing rapidly and in need of careful management to ensure their values are protected while others are under considerable threat of cumulative impact or have become degraded already and require more urgent or remedial action.
Our Role
The Department is the primary agency charged with protecting the environmental quality and integrity of the marine environment from the effects of waste discharges and infrastructure development. The Department fulfils this function by assisting the EPA in policy development and evaluating the environmental impact of proposals that may impact on the marine environment. The Department also uses its regulatory powers to ensure that proposals that are approved and implemented are carefully controlled and regulated to prevent pollution, degradation or loss of ecological and social values.
