In Brief | Marine environment

State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.

In Brief

This is a summary of Australia state of the environment 2011, which is an independent report presented to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities by the State of the Environment 2011 Committee

Marine environment

Main messages

The overall condition of the Australian marine environment is good.

Compared with the marine waters of other nations, Australia's oceans are considered to be in good condition. This is a testament to the limited pressures of the past century, combined with relatively good management of high–priority and emerging issues in recent years.

Areas near the coast are suffering.

Despite the overall good condition, there is substantial degradation in the east, south–east and south-west. Ecosystems near the coast, bays and estuaries in these regions are in poor to very poor condition. Much of the impact occurred in the mid–19th and 20th centuries, and recent impacts principally arise from unregulated human activities in river catchments, urban and coastal developments, and fishing. Aquaculture in coastal waters has resulted in major disease outbreaks that have affected the ecology of native species. Oyster reefs, which formerly occurred in many estuaries across the south–east region, were mined for lime in the 1800s and are now functionally extinct.

There are significant existing impacts on the oceans caused by human activities.

Fishing and offshore developments, particularly oil and gas extraction, all have local impacts on marine biodiversity, although the pattern of impact is different between the north and the south, and between the east and the west, aligned with the distribution and intensity of the pressures.

The ocean climate is changing and we need to prepare to adapt.

There are likely to be major impacts in the coming decades from rising sea levels, increased incidence and severity of extreme weather events, altered ocean currents, changing patterns of biodiversity, and changing productivity. Although there are currently only limited signs of changes in ecosystems, these will develop further and have important consequences for our coastal communities, wildlife and fishing. In particular, ocean acidification will have a major impact on marine ecosystems, since it can affect the base of marine food webs by diminishing the ability of planktonic organisms, which are food for many other organisms, to form shells.

An extended continental shelf has been granted.

Under the provisions of the United Nations Convention on the Law of the Sea, in 2008 Australia was granted a large (23%) increase in the seabed territory it controls. This is now 13.86 million square kilometres—the third largest national marine territory in the world's oceans.

Our understanding of major aspects of our unique marine biodiversity is limited.

Our knowledge of seabed geology and topography, oceanographic systems and physical processes has increased, but our knowledge of biodiversity and ecological processes remains limited. Ongoing research programs in marine biodiversity and ecological function are a high priority and, because our existing knowledge is dominated by information about fished species, it is particularly important to increase our understanding of non–exploited species and their roles in maintaining healthy and resilient ocean ecosystems.

The lack of a nationally integrated approach inhibits effective marine management.

The cumulative pressures on our marine ecosystems are rapidly growing. Present–day management systems lack integration among the various federal, state and local government systems that provide for planning, regulation and management of the marine and estuarine waters. This significantly impedes the design and delivery of effective policies and programs to maintain healthy and productive marine ecosystems and oceans. An integrated national system of multilevel governance for conservation and management would enable the natural wealth of our oceans to be maintained in the face of challenges, and would reward us with healthier oceans and increasing economic returns.

State and trends

Australia's oceans and coastal marine ecosystems are overall in good condition and have experienced only gradual decline, although there are many coastal areas where conditions are already poor or very poor. Indeed, some of the world's worst examples of impacts from pollution can be found in Australian waters.

While the overall health of our marine ecosystems is assessed as good, this finding is influenced by the good condition of the offshore waters and the remote coastlines of regions where pressures are lowest. In inshore waters near the coast of the south-west, east and south–east regions, and near urban areas and industrial developments, ecosystems are in poor health. Algal blooms occur regularly; natural levels of freshwater, sediment and nutrient inputs have been heavily altered; and worrying levels of pesticides are found in waters near areas of intensive agriculture. The ecosystem health of some nearshore marine waters and many estuaries is poor, particularly across the temperate areas and in many parts of the south–east region. The south–east region is assessed to be in the worst condition: most places are good, but the worst 10% of the region is poor—existing values are significantly impacted, and serious further degradation is expected within 50 years.

Marine biodiversity overall is in good condition, but nationally there are a number of areas on the coast, continental shelf and upper slope where the condition of some elements of biodiversity is very poor, as a result of the effects of human activities. Condition remains poor to very poor for a number of iconic species that have failed to recover from earlier impacts of excessive hunting and fishing, and some species continue to decline. These include Australian sea lions, which are unique to temperate southern Australian waters and are showing no substantial signs of population recovery from the hunting of previous centuries; and migratory wading birds, which appear to be continuing to decline across many of their Australian habitats. Southern bluefin tuna, formerly a major predator of our regional seas, has been fished to the edge of population survival but is now listed as conservation dependent under the Environment Protection and Biodiversity Conservation Act 1999; its global catch has been reduced and a management procedure has been proposed to rebuild the population. In addition to national–scale biodiversity problems, there are many more habitat and species issues in smaller local areas.


The Australian marine environment is experiencing a broad range of pressures that affect the quality of habitats, species and environmental health. The main pressures are in coastal areas, particularly in sheltered enclosed bays, estuaries and lagoons, where removal of land–based sources of pollution and wastes by flushing is most limited. These pressures and their impacts primarily affect the east, south–east and south-west regions; many parts of the north and north–west regions remain in near–pristine condition, although development pressures are rapidly increasing. This pattern reflects both the existing distribution of Australia's population and the distribution of the industries and activities that rely on coastal resources. However, the north–west is beginning to come under intense development pressures from the resource extraction sectors (oil and gas, mining, fishing, shipping). Only the marine values and assets of the north region remain relatively pristine, although even there, mining and river damming are growing pressures. The south–east region remains under the greatest stress, with a legacy of impacts from a wide variety of sources, and is suffering the greatest impacts from changing climate—the East Australian Current is changing its pattern of extension into Tasmanian waters, with an intensification of gyres (circular currents), and is becoming warmer and saltier.

Exploitation has overtaken waste disposal as the major source of impacts in Australia's oceans. A proliferation of oil and gas exploration and extraction, together with new energy and water systems and other shoreline industries, bring not only important initiatives in wealth generation, but also a major new set of risks to our waters that will require strategic and regional management. Nearshore development is proceeding quickly, replacing vegetated landscapes with hard surfaces that interrupt wetland functions and estuarine flows. Land–based sources of pollution and expanding pressure on coastal lands continue to be a significant concern despite strong improvements in land–use planning and the management of many point sources of pollution. Fishing has reduced most populations of sought–after species to low levels, mainly in previous decades. The maintenance of these low population levels by present-day management policies probably has significant flow–on consequences for the resilience and persistence of marine biodiversity in all inshore waters.

The major looming threat for our oceans and coastal waterways is the changing global climate, which is creating significant changes in ecosystems, biodiversity, shorelines and coastal lands. The main impacts of climate change for the marine environment are increased temperature, ocean acidification and sea level changes. Climate change threatens our wealth generation from the oceans, and the existence of our coral reefs at their present–day scale and grandeur.

Effectiveness of management

Many improvements in management systems at both state and national levels have produced substantial and persistent outcomes for marine ecosystems and biodiversity. These arise from programs devoting considerable resources to environmental protection and improvement of estuarine and coastal ecosystems across all jurisdictions.

Nonetheless, most of these efforts are poorly coordinated within jurisdictions and only weakly harmonised with a national approach, and there are no systematically derived regional objectives for marine biodiversity to guide strategic planning or management. Each region has a specific set of pressures that will almost certainly worsen over the coming 20–50 years, given current management arrangements. For example, in the north–west, while many habitats and species populations are in nearpristine condition, more impacts will occur with the escalation of the oil and gas industry. There is limited federal leadership in the implementation of an effective national system for management of coastal marine ecosystems and biodiversity, and their protection from persistent and emerging threats. There is continued loss of biodiversity, duplication of effort, inefficiencies, an overall lack of effectiveness, and distrust among the sectors, the various jurisdictions and the community. A vertically and horizontally integrated national system for marine conservation and management is widely seen as a critical gap in management.


The overall outlook for Australia's marine environment is uncertain–most aspects are currently not in decline, and those that are declining have moderately well understood underlying pressures and drivers. Of those assets and values that are already in poor condition, very few are recovering.

The interaction of accelerating changes in the climate with existing land uses, fishing systems, shoreline industries and new risks is presenting ocean management with unprecedented challenges. There is a plethora of responses to this situation, many of which are achieving good outcomes; some are reducing pressures, and holding the ecosystems and biodiversity in good condition. However, the evidence shows that our management systems are still too fractured, weakly coordinated and poorly integrated to halt the accelerating degradation of the unique values of our oceans and coastal ecosystems. The early signals of such decline are now evident across a number of areas of our coastal waters.

We need our oceans and coastal ecosystems to continue to sustain and inspire Australia's future, as they have in our past. Perhaps the most critical challenge of all now confronts us—our ability to design and deliver effective and efficient governance to address the known threats and accelerating risks to our unique marine environment.