Ten Themes in Coastal and Marine Studies
1. Indigenous People
Coastal Aboriginal people have been users and custodians of Australia's marine environment for over 40 000 years. When Aborigines and Torres Strait Islanders fish, they fish on traditional lands for a subsistence food source. Fishing spots are part of their cultural and traditional knowledge. Aboriginal and Torres Strait Islander communities have watched their traditional fishing areas being polluted, over-fished, widely publicised and irrevocably changed. They have fundamental indigenous rights to manage, use and protect traditional country including marine and inland waters.
Marine conservation management plans in the Australian Government's marine program recognise the special interests of coastal Aboriginal people and Torres Strait Islanders and seek to involve them in all aspects of planning and management.
The ocean is the cradle of life on earth. Of the 33 major animal groups or phyla, 28 are found in the sea. Life forms, life histories and ecological processes are very different in the sea than on land. The reproductive cycles of marine organisms are often closely linked to water movements and most often have spores or larval stages, some of which are dispersed over large distances. Because of the vagaries of ocean currents the populations of these organisms in a given area can vary from year to year. Marine species, bathed as they are in water, are particularly vulnerable to water-borne pollutants. These differences often necessitate different approaches to marine environmental policy, management and conservation.
Australia's coastal zone organisms are notable for their high proportion of endemic (found only in one area) species. 80% - 90% of the species of marine groups are endemic, or restricted to the temperate southern regions. Very little is known of the true extent of marine biodiversity and many marine organisms remain undescribed. Given that so little is known, precautionary management strategies are important for the conservation of marine biodiversity. Networks of marine protected areas are important as a "catch all" strategy for protecting the majority of species.
3. TransportAustralia is an isolated island continent with a long coastline and shipping is a major economic use of the seas, estuaries and coastlines. Australia ranks as the fifth largest user of shipping in the world. Each year there are around 12 000 overseas shipping arrivals with almost 380 million tonnes of freight. Shipping and port operations produce a variety of environmental impacts including pollution by contaminants and introduction of exotic species in ships' ballast waters or attached to ships' hulls. Port operations lead to loss of habitat from reclamation and dredging, and increased sediment pollution by oil, litter and anti-fouling paints. While ports are among the most disturbed marine environments, technical engineering and management solutions do exist to prevent or minimise many impacts.
4. Introduced SpeciesAs international trade expands, the number of exotic species arriving as stowaways at the world's ports increases. At least 55 species of fish and invertebrates and a number of seaweeds have been introduced either intentionally for aquaculture or accidentally in ships' ballast waters. Blooms of introduced toxic marine algae are a serious problem in Tasmanian and Victorian waters. The Japanese starfish, Asterias amurensis, has established around Tasmania and threatens biodiversity, aquaculture farms and scallop and abalone fisheries. The population of Asterias, in the Derwent estuary is now estimated at 28 million making it the dominant species in the local benthos (bottom-dwelling organisms).
5. Recreation and Tourism
The beach and marine environments are socially and culturally important to Australians. The beach is a major centre for outdoor activities such as bathing, surfing, fishing, boating, exercising and relaxing. The sea also provides inspiration for artists, writers, musicians sailors, adventurers and "ordinary Australians". Recreational fishers are increasingly competing with commercial fishers for dwindling stocks. One survey estimated over 4.5 million Australians go fishing at least once per year. Recreational and sports fishing is also a significant attraction for tourists.
Australia's natural environments, particularly coastal regions, are a major draw-card for overseas tourists. Coastal and marine ecotourism is a fast growing industry in Australia. Although tourism and recreation are generally considered to be 'clean industries' they have many impacts on parts of Australia's coastal strip. Tourist facilities, accommodation, transport and other infrastructure are typically placed close to a particular attraction. Effects of recreational facilities and activities include: dune erosion, loss of habitat, declines in wildlife and fisheries, decline in water quality, destruction of cultural sites, loss of amenity, crime, traffic congestion and building congestion.
6. Marine Protected Areas
A Marine Protected Area (MPA) is any area of intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, that has been reserved by law or other effective means to protect all or part of the enclosed environment. MPAs are a very important legislative tool for marine conservation and management, particularly in protecting biodiversity and achieving sustainable use of marine resources. MPAs can serve the following purposes: conserve nature, protect fish resources, protect cultural heritage and provide tourism, recreation, education and research opportunities.
In 1992 Australia had 303 MPAs with a total area of 463 200 square kilometres. About 5.2% of Australia's marine environment is protected as MPAs with about 94% of MPAs lying within the Great Barrier Reef Marine Park. However, existing MPAs are not adequate to ensure the protection and management of marine biodiversity. Most MPAs are also threatened by activities occurring outside their boundaries. These threats include pollution from land run-off, and coastal development.
7. Urban Development
Over 80% of the Australian population reside inside the coastal zone. Urban development in the coastal zone has major impacts on the coastal and marine environments. These impacts result from coastal engineering structures including breakwaters and seawalls associated with ports, harbours, canal estates and marinas, and reclamations. Estuaries and the coastal lakes and lagoons in the south-east have been particularly affected by seawall construction. There have also been significant local losses in saltmarsh, mangrove and seagrass habitats. Beach and dune erosion is an increasing problem in many areas.
As a result of poor integrated planning and population pressures, coastal strip developments have led to a decline in water quality, loss of habitat, beach erosion, conflicts among users and loss of amenity. Micro-organism associated with sewage outfalls, septic seepage, stormwater and excess nutrients find their way into the marine environment from urban developments.
Fish caught from commercial activities are important for local consumption and export. Australia has a number of high value export fisheries such as abalone, rock lobsters, prawns and cultured pearls. Annual exports of marine products are valued at $1.1 billion annually.
Fishing is a major extractive use of the marine environment and can impose heavy pressure on marine species and their habitats. Most major Australian seafood species are now fully exploited. Some including southern bluefin tuna and eastern gemfish have been over-exploited. Of 100 of Australia's fisheries several are considered to be over-fished and more than twenty are fully or heavily fished. Reasons for declines in some fisheries include: over-fishing, use of non-selective fishing gear, loss of habitat, pollution and Australia's marine jurisdictional complexity which can hinder management.
9. Catchment Management and Water Quality
Declining water quality is regarded as one of the most serious issues affecting Australia's marine and coastal environments. Land and sea are closely linked in the coastal zone. Some of the activities that contribute to poor water quality include inappropriate catchment management, land use practices, sewage discharge and urban run-off.
Elevated nutrients and sediments come from land run-off both in rural and urban areas. Sediments alter estuaries and shores and smother marine life. Elevated nutrients cause eutrophication and the harmful growth of algae. Eutrophication is a serious threat to estuaries, temperate seagrass and tropical corals. Increased sedimentation and nutrients have been linked to massive die back of seagrasses in many areas. Seagrass beds are ecologically important because of their high productivity, ability to trap and stabilise sediments, provision of fish habitat and habitats of important species such as dugong and turtles.
Scientists have estimated that in Queensland the amounts of sediments, nitrogen and phosphorus entering the sea each year have increased three to five times since European settlement. The rivers of Queensland's east coast catchments are estimated to deliver 14 million tonnes of sediments to marine ecosystems annually. Other pollutants include: industrial chemicals, pesticides, heavy metals, pathogens and litter.
Marine organisms can be affected by a range of discharges into the environment, and emissions including oil, sediments, nutrients, sewage, heavy metals, organochlorines and litter. Up to 50% of these emissions enter the sea from the land.
Australian coastal ecosystems are particularly vulnerable to eutrophication as they evolved under very low nutrient regimes and are dominated by nutrient sensitive corals in the north and seagrasses in the south. Eutrophication occurs when excess nutrients enter the marine ecosystem in run-off from farming lands and sewage and storm-water run-off from urban areas. The increased nutrient levels lead to an increase in marine plant (algae) growth. As these plants decay they deplete the oxygen content of the water and marine animals die in large numbers.
While large oil spills grab headlines, far more oil actually enters the marine environment from industrial, sewage and stormwater discharges and operational discharges from ships. Refined petroleum contains polycyclic aromatic hydrocarbons [PAHs] that are carcinogens and have been implicated in a wide range of human health problems and diseases in aquatic organisms. PAHs also accumulate in animal tissues.
Heavy metals such as copper, lead, cadmium, zinc and mercury have become serious contaminants in estuaries and coastal waters. Heavy metals tend to attach to suspended particles in the sea and ultimately accumulate in sediments. They also bioaccumulate in fish, molluscs, algae and seagrass. Heavy metals enter the marine environment via stormwater run-off, industrial effluents, sediments from mining operations and atmospheric fall out.
A range of organochlorines, including 2,4-D, 2,4,5-T, lindane, chlorinated phenols and PCBs, enter the marine environment from industrial effluents and run-off from agricultural lands and accumulate in sediments. Although these organochlorines are present in low concentrations, they are preferentially soluble in animal fats and accumulate in the tissues of predatory fish, seabirds, marine mammals and humans.
Ocean and beach litter not only reduce the beauty of our beaches but can also endanger marine life. Worldwide many thousands of marine mammals, turtles and sea birds die each year from swallowing plastic bags or being trapped in discarded fishing gear. In Australia the incidence of entanglement of fur seals, turtles and dugong in net fragments and other litter is alarmingly high. Australian beaches are increasingly littered with plastic bottles, plastic bags, fishing lines, nets and other rubbish. The fishing industry is a major contributor of ocean litter. Surveys in Tasmania show 80% of litter items came from recreational and commercial fishers. Not even remote beaches are free from this litter.