Our Sea, Our Future
Major findings of the State of the Marine Environment Report for Australia
Compiled by Leon P. Zann
Great Barrier Reef Marine Park Authority, Townsville Queensland
Department of the Environment, Sport and Territories, Canberra (1995)
ISBN 0 642 17391 5
It is not possible to simply and precisely assess the state of Australia's marine environment because of its vast size and great diversity, the diversity and complexity of issues affecting it, and the great gaps in our scientific knowledge of it.
However, on the basis of the existing limited information, and in comparison with both neighbouring countries and equivalent developed countries in the northern hemisphere(93),(95), the condition or 'health' of Australia's marine environment might be rated as 'generally good', but with many important caveats or qualifiers.
The condition of specific areas ranges from 'almost pristine' in very remote, undeveloped areas(12),(42-47),(73),(75),(76),(81),(85), to locally 'poor' off many highly developed urban, industrial and intensively farmed areas in the south-east(42-47),(51-55), and south-west(56) of the continent. The condition of offshore environments is better than inshore environments because of dilution of pollutants(45).
Most of our marine environment is far removed from the major population centres and is little affected by most human activities. The northern(57), far north-eastern(51),(69) and most of the western coasts(57) of the continent, the Great Australian Bight(55) and Australia's External Territories(73) in the Indian Ocean, South Pacific, Southern Ocean and Antarctica(75) are amongst the least polluted places on earth.
Australia's population is highly concentrated in coastal cities in the south-east and south-west. Here the state of the adjacent marine environment may be locally poor(51-56). So while the state of Australia's marine environment is on average, good, the state of the marine environment near where the urban Australian lives is often 'not good'.
The top five concerns
- Declining marine and coastal water/sediment quality, particularly as a result of inappropriate catchment land use practices.
- Loss of marine and coastal habitat.
- Unsustainable use of marine and coastal resources.
- Lack of marine science policy and lack of long-term research and monitoring of the marine environment.
- Lack of strategic, integrated planning in the marine and coastal environments.
Figure 138: Land and sea are closely linked in the coastal zone. Catchment uses in Australia have had major effects on estuaries and inshore waters.
1. Declining water quality
Declining water quality and sedimentation were regarded as probably the most serious issues affecting Australia's marine and coastal environments. Land and sea are closely linked in the coastal zone. Elevated nutrients and sedimentation are largely the result of inappropriate catchment land use practices, sewage discharges and urban run-off.(1),(6),(40),(42-47),(51-57)
- Sediments and nutrients Elevated nutrients and sediments come from land run-off. Land erosion is the major source in rural areas, and sewage and urban run-off is the major source in urban areas. Sediments alter estuaries and shores and smother marine life. Elevated nutrients cause eutrophication, the harmful growth of algae. Blooms of blue-green algae are now common in many estuaries and bays. Blooms of introduced and native species of toxic dinoflagellates (microscopic algae probably introduced in ships' ballast waters) are a serious problem in Victoria and Tasmania, and threaten other States. Eutrophication is a serious threat to estuaries, temperate seagrass and tropical corals (next page).(1),(4),(6),(10),(12),(42),(51-56)
- Oil pollution The major source of oil entering the marine environment is urban run-off. Small but frequent spills from fuelling vessels in ports; and operational discharges from ships are also a significant source. Australia has been lucky so far; only two major spills (over 1,000 tonnes) have occurred, and these resulted in little long-term damage. A series of smaller spills since 1990 has caused greater damage to wildlife.(36-39),(43)
- Heavy metals Pollution from mercury, cadmium, lead and other heavy metals is a localised problem. Levels of heavy metals are high in seafood in Torres Strait; while mines in Papua New Guinea were implicated, preliminary research suggests that high levels are natural. Localised heavy metal 'hotspots' include Lake Macquarie (NSW), Corio Bay (Vic), Derwent and Macquarie Estuaries (Tas) and Port Pirie (SA). Tributyl tin from ships' antifouling paints is also a problem in many ports and marinas. Controls on industrial discharges and ships' antifouling paints have reduced levels in most areas monitored.(44),(52-57)
- Organochlorines Some organochlorines or chlorinated compounds used as herbicides and insecticides in industry are toxic to marine life and are bioaccumulated or magnified in marine food chains. Away from farm lands and cities in Australia, levels are very low. Local 'hotspots' include Sydney's sewage outfalls and Homebush Bay and off Melbourne's Port Phillip Bay sewage outfalls and Corio Bay.(45),(52),(53)
- Beach and ocean litter Litter is a growing and very conspicuous problem on our beaches. Urban beaches are most affected but not even the remotest beach is free from litter. Litter reduces the scenic and recreational values of areas, and may affect wildlife. Turtles and whales may die from eating plastic bags. The incidence of seal entanglements in net fragments and other synthetic material in Tasmania is one of the highest in the world.(18),(46),(53),(54)
2. Loss of marine and coastal habitat
Many of the environmental issues identified are related to water quality and loss of habitat, and are overlapping in nature.(7-14),(51-57)
- Degradation of estuaries and coastal lakes Estuarine environments in much of eastern and southern Australia are declining because of eutrophication and sedimentation, acid soil run-off, coastal developments, loss of habitat and overfishing. South-eastern and south-western coastal lakes, which have limited ocean water exchange, have been particularly affected by terrestrial run-off.(6-8),(51-57)
- Declines in temperate seagrass Seagrass beds are very important ecosystems. Elevated nutrients and sediments have caused serious die-backs of temperate seagrass beds in southern Australia. Around half of the seagrass in the estuaries of New South Wales has been lost. The majority of seagrass in Victoria's Western Port has been lost. Tasmania, the South Australian Gulfs and south-western Western Australia have also suffered locally serious declines in seagrass. A major loss of sub-tropical seagrass occurred in Hervey Bay in Queensland, causing a serious decline in the dugong population.(10),(42),(51-56)
- Loss of mangrove and saltmarsh habitats Significant losses of saltmarsh and mangroves have occurred near urban areas through reclamations, drainage and other developments. This affects fish and other sea life which use these as nurseries and feeding grounds.(6-8),(51-57)
- Unsustainable coastal development Urban, industrial and port development, tourism and other uses have been responsible for significant degradation in the coastal strip in many areas around Australia, particularly in the south-east. (1),(29),(40),(51-56),(62)
- Effects of fishing on sea floor communities There is widespread concern about the environmental effects of trawling and scallop dredging on the sea floor community and on juvenile fish. The effects of fishing on the ecosystem are little known, but is likely to be significant and widespread. The large number of seabirds caught on tuna longlines is of growing concern. (30),(32),(34),(51-56),(69)
- Introductions of foreign species The introduction of exotic pests and diseases via ships' ballast water is a potentially very serious problem in Australia's long isolated marine environment. Around 55 species are known to have been introduced, largely via ships' ballast waters and on ships' hulls. Blooms of introduced toxic marine algae and the ravenous Northern Pacific seastar threaten marine communities and aquaculture farms. The possible introduction of diseases such as cholera via ships' ballast waters is also of concern.(14),(47),(48),(53),(54)
- Population increases in native species Outbreaks of the coral-eating crown-of-thorns starfish has resulted in significant loss of corals in the central one third of the Great Barrier Reef, and on the Tasman Sea reefs. Similar outbreaks of the coral-eating Drupella snail have affected large areas of Western Australia's Ningaloo Reef. The causes of the outbreaks are unknown. (49),(50),(51),(56),(69),(70)
3. Unsustainable use of marine and coastal resources
Over-harvesting of fish and other marine life, coastal developments, and conflicting resource use, are critical issues around Australia.(29-35)
- Declines in fish stocks Australia is not rich in fisheries. We have experienced declines in some commercial fisheries over the past few years. Serious overfishing of southern bluefin tuna, southern sharks, gemfish, rock lobsters and other species has occurred. There is also a serious lack of accurate catch data on many of Australia's fisheries.(30-34)
- Inappropriate fisheries practices Harvesting practices used in certain fisheries are causing significant impacts on marine ecosystems and habitats. Of particular concern are the impacts of trawling and scallop dredging on sea floor communities.(84)
4. Lack of marine science policy
Little geographically comprehensive and long-term scientific information is available on the marine environment. Without this it is difficult to accurately assess its condition, to identify trends, and to design and assess management programs. Many of the findings in SOMER are therefore based on limited data sets, descriptive information and expert scientific opinion.(1-57),(63)
- Lack of long-term research and monitoring of Australia's marine environment Difficulties in establishing long-term research and monitoring programs include: high cost of marine studies; difficulties in obtaining long-term funding for research and monitoring; lack of coordinated data acquisition and storage; and lack of standardised, cost-effective, statistically based scientific sampling techniques and indicators. (6-18),(28-57)
- Lack of applied scientific knowledge on the marine environment Local government environmental managers are highly critical of the lack of information on local marine environments, and the lack of simple, descriptive maps and inventories(51-57),(62).
- Lack of scientific understanding of the functioning of marine ecosystems Marine scientists are more concerned about the lack of understanding of how marine ecosystems function. They argue that effective management must be based on this.(6-18)
5. Other issues
- Lack of integrated planning in the coastal zone Many of the problems identified in SOMER stem from the lack of integrated, long-term planning in the coastal and marine environments (1-47),(51-57). Australia does not have a clear direction or agreed national strategy for managing its marine or coastal environments.
- The lack of strategic planning in the coastal zone has been identified as a major problem in a number of Commonwealth and State inquiries, most recently the Resource Assessment Commission's Coastal Zone Inquiry. Coastal zone management must consider the high degree of connection of land and sea (particularly catchment uses), the many human activities which span the land/sea interface, the wide dispersal of marine organisms and pollutants by currents, and the different administrative jurisdictions involved.(1-47),(51-57),(62)
- Lack of non point-source (diffuse) pollution controls Guidelines and standards have been developed for point-source discharges. However, no guidelines have so far been developed for the multiple, non-point source or diffuse discharges from catchments. Constant, low levels of a range of different types of pollutants can have very serious chronic and cumulative effects.(42)
- Insufficient representation of marine protected areas (MPAs) About 5.2% of Australia's marine environment has some level of protection. However, a very large proportion of protected areas (74%) is the Great Barrier Reef Marine Park. Many of Australia's marine bioregions are not sufficiently represented in MPAs.(67),(77-80)
- Indigenous issues Outside the Northern Territory, the legal uncertainty as to the existence of customary sea rights for Aboriginal and Torres Strait Islander peoples, their general lack of involvement in environmental management and lack of commercial opportunities in fisheries and tourism are important social issues. The 1993 Native Title Act caters for both customary land and sea rights. However the issue of the existence of sea rights has not yet been the subject of an authoritative decision by a court.(20-22),(84)
- Social and cultural values of coast and sea Despite the obvious great importance of the coast and sea to Australians, knowledge of the social or cultural values of the marine environment is limited. Social and cultural values are generally inadequately considered in coastal zone planning and management.(23)
6. Regional issues
Hundreds of regional issues were raised in SOMER. The most serious include:
- Condition of marine and coastal environments in south-east and south-west The widespread degradation of estuaries, coastal lakes and bays in New South Wales, Victoria, Tasmania, South Australia and south-western Western Australia is a serious local and national problem. Major causes are elevated nutrients, sedimentation, pollution, coastal strip development and overfishing. Of particular concern are the unique coastal lakes which are not found in the less populated and less degraded north.(42-47),(51-56)
- Condition of 'urban' marine environments Estuaries and coastal waters near the State capitals are generally the most disturbed parts of the marine environment. Some parts of Sydney Harbour, Port Phillip Bay, and the Derwent Estuary are so polluted by sewage, urban run-off and industrial discharges that they are frequently closed for bathing and fishing. However, controls on discharges are having an effect and most contaminated areas are showing signs of improvement.(42-47),(51-56)
- Elevated nutrients and sediments in the Great Barrier Reef lagoon Elevated nutrients from land run-off may be threatening the inner Great Barrier Reef. Corals are particularly sensitive to elevated levels of nitrates and phosphates. Some scientists fear the Great Barrier Reef lagoon, the waters between the mainland and the Great Barrier Reef, is eutrophic.(42),(51),(69)
The most serious issues in Australia's marine environment stem from poor catchment use, and therefore declining water quality. Increased levels of nutrients and sediments are the major problems.
The most serious consequence of these are die-back of seagrasses in temperate Australia(10) and threats to inshore corals in the wet tropics(12).
The major causes are soil erosion and declining inland water quality, two of our greatest problems on land(1). The crisis in Australia's inland waters is well accepted. Elevated nutrients from soil erosion, agricultural fertilisers, live stock, sewage and urban run-off has resulted in regular blooms of toxic algae(14,42,53-55). Not so well accepted is that this then becomes a problem in estuaries, coastal lakes, bays and coastal waters. Degradation of estuaries and die-back of seagrass cause declines in coastal fisheries(31).
The key issues are thus interrelated. Because the major source of marine environmental threats lie inland in the catchments, strategic, integrated planning and management in the coastal zone is of paramount importance. Integrated catchment management is probably almost as important to the sea as it is to the land.