Coasts and oceans
Theme commentary
Trevor J Ward, Greenward Consulting, Perth, Western Australia
Alan Butler, CSIRO Marine and Atmospheric Research, Brisbane, Queensland
prepared for the 2006 Australian State of the Environment Committee, 2006
Contributions and pressures
Ecosystem services
Ecosystem services are the processes through which ocean ecosystems produce resources that are often taken for granted, such as clean and healthy beaches for surfing, productive habitats for fisheries, moderation of the extremes of coastal temperatures that make coastal areas more habitable, and the recycling and relocation of nutrients derived from land runoff. These services are maintained by retention of the natural structure and function of the ecosystems, such as the natural functioning and diversity of seagrasses, primary production in benthic and pelagic systems, and clear waters allowing light penetration into the water column (Daily et al. 1997).
There have been no documented, large-scale failures in Australia’s ecosystem services, but there are many locally important problems in Australian coastal and ocean ecosystems. The lack of evidence of large-scale changes may well be related more to a lack of knowledge than to a lack of change. The examples highlighted in this report serve as early warning indicators for Australia that better monitoring of conditions and more effective responses to emerging issues in coastal and ocean ecosystems need to be urgently implemented. Australia’s Oceans Policy is the main policy response to these broad scale ecosystem issues, but the policy is having only limited success, and so far provides no system for national (or regional) monitoring and assessment of ocean ecosystem services.
Water quality
The discharge of sewage and stormwater, land runoff, groundwater and river inputs of nutrients and sediments to estuaries and the coastal waters is arguably Australia’s greatest coastal management challenge (NLWRA 2002). All capital cities discharge sewage and stormwater to estuarine and marine waters, and much of this receives only minimal treatment—stripped only of solids and rubbish, but not of nutrients, hormones, disinfectant breakdown products, nor of a range of resistant viruses. Stormwater from urban areas is discharged after minimal treatment to reduce large solids (such as plastics and industrial rubbish), but otherwise contains untreated road and garden runoff, with oils, rubber particles, fertiliser, nutrients and sediments. River catchments are major sources of nutrients, sediments and a range of agricultural and veterinary chemicals, all of which affect estuarine flora and fauna; where river inputs are large, coastal ecosystems are adversely affected. Unfortunately, there are no national-level data on the impacts of these non-point source discharges on the coastal and marine ecosystems and biodiversity.
There is growing concern globally about the range of chemicals that enter sewage treatment plants—from human waste or from industrial wastes. These chemicals are not routinely monitored in treatment processes. Sewage discharges of these chemical and nutrients can be highly significant at local scales because they have a chronic daily delivery concentrated at a point source. For example, although water-industry monitoring found no evidence of sewage impacts in the exposed coastal waters of metropolitan Perth, scientific studies found that Perth’s sewage discharge leads to algal blooms, reduction of light penetration by one-third, increase in nitrogen by three to five times natural backgrounds, and more than a doubling of phytoplankton biomass (Thompson and Waite 2003). Furthermore, in NSW waters, it is estimated that 30 to 50 per cent of nitrogen in one species of reef fish is derived from nitrogen discharged in sewage (Gaston et al. 2004).
Industrial facilities discharge nitrogen, ammonia, phosphorus and sulphuric acid to coastal waters, and volatile organic compounds and hydrogen sulphide to offshore waters . In coastal waters, the metal refining industry has created intense pollution problems around several Australian smelters. For example, in the Northern Territory, the ongoing discharges from the major alumina refinery at Gove have created a 70 hectare marine ‘dead zone’ in the adjacent harbour (Alcan Grove Alumina Refinery 2004), and pollutant impacts may extend further into adjacent bays and seafood (Figure 3.1).
Various forms of responses have been developed to deal with these issues. To protect the biodiversity structure and function of the inshore reefs of the Great Barrier Reef, the Reef Water Quality Protection Plan is intended to reduce inputs of sediments, nutrients and pesticides (GBRMPA 2001). In South Australia, sewage and stormwater programs to reduce the load of nutrients have been initiated to improve the water quality of St Vincent Gulf near Adelaide (South Australian Government 2006).
The most visible indicator of coastal eutrophication is excess blooms of phytoplankton and benthic macroalgae; extensive mortality of seagrass beds has been one of the most commonly documented features of Australian coastal eutrophication (Price 1995). There is no systematic monitoring and reporting of algal blooms in Australia’s estuaries and coastal waters, so there is no way of knowing if eutrophication is increasing or decreasing as a national problem.
Fisheries
Fishing is the most widespread activity in marine ecosystems. Australia’s commercial fisheries exploit more than 300 species of fish and invertebrates, and operate in all areas of inshore and offshore waters, including the Antarctic region. While the productivity of Australia’s fisheries is limited compared to those of some other countries (because of the generally low nutrient status of Australia’s oceans), they nonetheless provide for an important source of wealth and recreation in most coastal areas of Australia.
The commercial fisheries are concentrated on high-value but low-tonnage benthic species. In 2003–04, the commercial wild-catch fisheries produced about 228 000 tons of seafood , valued at about $1.56 billion (ABARE 2005). The main component of this is generated by state and territory-managed coastal fisheries (151 000 tons, $1.15 billion), with Commonwealth-managed fisheries generating about half of that (77 000 tons, $0.34 billion). The value of Western Australia’s fisheries alone in 2003–04 ($396 million), mostly due to the Western Rock Lobster fishery, exceeds the combined value of the Commonwealth-managed fisheries.
It is difficult to find consistent data to demonstrate changes over time in the condition of stocks (see Table 1 and Table 2). While many of the state-managed fisheries appear to be stable, some appear to be overfished (see, for example, NSW Department of Primary Industries 2004). However, for many of Australia’s state-managed fisheries, there are no biomass reference points to determine the condition of the stocks, few reliable data, and no fully independent assessment of fish stocks or the fisheries (other than the Marine Stewardship Council’s assessment of the Western Rock Lobster fishery in Western Australia).
In contrast, there are much more accessible and verifiable data for Commonwealth-managed fisheries, and they show an alarming trend in stock conditions. Over the past 12 years, amongst the 74 species that are Commonwealth-managed, there has been an increase in the number of stocks that are overfished , or have inadequate knowledge to make a decision (Figure 4). Some 23 per cent (17 species) of fish stocks are currently overfished (or inadequately known)—this is an all-time record high (BRS 2004). This current trend of increasing numbers of overfished species is not consistent with sustainable management of Australia’s fisheries and, as for global fisheries (FAO 2004), urgent conservation action is now required in Australia to restore commercial fish stocks.
In November 2005, the Australian Government announced a $220 million national fisheries structural adjustment programme to deal with this problem. The package aims for a major reduction in permitted catches across a number of Commonwealth-managed fisheries. It also includes considerable structural adjustment to compensate fishers for the catch reductions and business disruption. This response is designed to take a large fraction of the fishing effort permanently out of these fisheries, and allow stocks to recover from their currently overfished conditions.
Source: BRS, 2004
The EPBC Act requires that all Commonwealth-managed fisheries undergo strategic environmental impact assessment, and that all fisheries with an export component undergo assessment to determine their sustainability. Fisheries assessed under the Act may be permitted to export products or they may be prohibited. Up to April 2005, 11 Commonwealth-managed and 69 state-managed fisheries held approvals to export products, and no fisheries have been classified as Prohibited. A further 31 fisheries were in various stages of the assessment process (DEH 2005).
Recreational fishing is responsible for substantial catches of fish and invertebrates that are taken mostly from nearshore waters in the most populous states, but increasingly also in remote areas of the mainland and the offshore islands. A national survey of recreational fishing estimated that between May 1999 and May 2000, 3.36 million people participated in recreational fishing, catching about 136 million individual animals. This included more than 12 500 tonnes of the most popular species, and where there are comparable data, it has been estimated that for some of these species, the recreational catch exceeds the commercial catch. In 2004, domestic and international visitors alone are estimated to have spent 40 million trip-nights, and at least $3.4 billion on various aspects of recreational fishing.
Few recreational fisheries are fully managed, in the sense that stocks are assessed and fishing effort is controlled appropriately to ensure adequate levels of breeding populations are maintained. The lack of effective control mechanisms over recreational fishing pressures increases the risks of overfishing and degradation of the fish populations. As Australia’s population increases and more people fish, the pressures on fish stocks will increase. At present there is almost no systematic collection of recreational fishing data, and so trends in recreational effort, including possible effects on sensitive species that are highly targeted by recreational fishers, such as Mulloway (Argyrosomus hololepidotus), and the resulting impacts on fish stocks are virtually unknown. These issues are well recognised by fishery managers in all states and territories, and there is an increasing focus on improving the management of recreational fishing for highly sensitive species.
All fisheries (commercial, recreational, subsistence and Indigenous) have direct impacts on non-target species and habitats, and indirect impacts on species that are ecologically linked to the species being caught. The effects of target catch, bycatch, and possibly habitat degradation, in Commonwealth and state-managed fisheries, have had a major impact on sharks, rays and sawfish, and there is a high level of concern over the illegal catch of sharks from tropical waters for finning.
The tuna fisheries set more than 70 million baited hooks on longlines in Australian waters in the five years from 1998 to 2002. Of the 21 species of albatross that occur in Australian waters, 13 have been caught as bycatch on longlines (AFFA 2003), and all these species have been observed caught on longline hooks elsewhere in their geographic range. Thirteen other species of seabirds have also been observed killed on longlines in Australian waters, including petrels, gannets and skuas.
Australia’s Northern Prawn Fishery extends across about 6000 kilometres of the northern Australian coastline, through Queensland, the Northern Territory and Western Australia, and catches about 8500 tonnes of penaeid prawns each year. In addition, catches are dominated by a wide range of unwanted (and ultimately discarded) bycatch species , including at least 330 species of fish, 56 species of sharks, stingrays and sawfish, 13 species of sea snakes, five species of turtles, and hundreds of species of benthic invertebrates (Stobutzki et al. 2001b, Pender et al. 1992, Brewer et al. 1998)
In response to these concerns, the Northern Prawn Fishery has implemented a number of bycatch reduction initiatives , which have substantially reduced the annual catch of turtle, sharks and rays. Fishing reduces the abundance of target stocks and, if fishing intensity is high enough, the numbers of fish available for natural predators may become highly depleted. The history of Australia’s Southern & Eastern Scalefish and Shark shows that, since the fishery commenced in 1915, fishing has greatly altered the biodiversity of the continental shelf and deeper water ecosystems. While flathead (Platycephalus) remains the main target species in the fishery, the mix of other exploited species has changed substantially. The spawning biomass of tiger flathead (Neoplatycephalus richardsoni) in this area, for example, has been reduced from about 27 000 tons in 1915 to about 7000 tonnes in 2004; and leatherjackets and Latchet (Pterygotrigla polyommata) have now almost disappeared from catches in the fishery (Klaer 2001). Since the 1970s, the catch rates of sharks and rays in the fishery have also declined dramatically, and populations of most of these species are now at very low levels (Graham et al. 2001).
A qualitative analysis of the ecological risks from fishing in 14 Commonwealth-managed fisheries identified sharks and rays as a group that has a higher level of risk from the impacts of fishing than the other groups considered (Hobday et al. 2004). These species are mainly predators and, although climate change and habitat destruction may also have important impacts, fishing impacts are likely to be very important.
Commonwealth-managed fisheries are developing bycatch action plans. Also, ecological indicators to report on impacts are being developed for Commonwealth-managed fisheries (Fulton et al. 2004). Without a comprehensive reporting system for bycatch and ecological impacts that parallels a system for commercial stocks for all Australian (state, territory and Commonwealth-managed) fisheries, there can be no comprehensive national analysis of the condition of fish stocks and the impact of fishing.
Aquaculture
Australia’s main aquaculture products are pearls, Atlantic Salmon (Salmo salar), Southern Bluefin Tuna (Thunnus maccoyii), oysters (two species), and a range of other mollusc and finfish species. Production has increased during the past decade, from $494 million in 1994–95 (in 2003–04 dollars) to $732 million in 2003–04. The relative value of aquaculture also continues to increase, contributing 34 per cent of the gross value of production of all fisheries in 2003–04 (ABARE 2005).
While land-based aquaculture is increasing, most of Australia’s production is still sourced from in-water aquaculture activities. These activities tend to be concentrated in coastal regions of high water quality, which are usually also areas of high conservation value. The allocation of highly sensitive inshore sites for aquaculture operations in all states and the Northern Territory has generated widespread concern about the biodiversity and ecosystem impacts of these activities. The main ongoing pressures related to in-water aquaculture ventures are:
- water and sediment pollution (nutrients, biocides, antibiotics, diseases) around installations
- alienation of highly environmentally sensitive inshore habitats for sea-cages and supporting shore-based infrastructure
- the overharvesting of pelagic species to provide feed for farmed species
- the wild catch of immature fish that would otherwise contribute to maintenance of a natural wild breeding population of that species
- the escape of cultured species into the wild and their consequent impact on local populations of prey species and the gene pool of native species
- attraction of predators and entraining of birds and mammals on facility wastes or escapes
- the introduction of diseases into the local region
- the risk of catastrophic failure of installations under storm and cyclone extremes.
Perhaps the worst ever fish kill from human causes is the massive series of pilchard kills that repeatedly occurred across temperate Australian waters (from Western Australia to New South Wales) in 1995 and again in 1998–99 (reported in SoE2001). The fish kill episodes were observed across more than 4000 kilometres of temperate Australian coastline and, although there has been no attempt to estimate the total mortality of pilchards, mass fish mortalities of this scale are of national and probably global importance. It is unlikely that the precise cause of these fish kills will ever be known, but the most likely source of the virus thought to be responsible is the frozen, but otherwise unprocessed, food used for aquaculture sea-cages in South Australia (Griffin et al. 1997, Gaughan et al. 2000). Food for aquaculture purposes is now more systematically managed to reduce the risk of such disease importations re-occurring, but the virus that affected the pilchards is probably now well established in Australian marine ecosystems and likely to have ongoing impacts on the pilchard population and species that depend on this fish (such as penguins).
In New South Wales, the stick and tray aquaculture industry produces about 100 million Sydney Rock Oysters (Saccostrea glomerata) a year, valued at about $35 million in 2003–04. In June 2004, an outbreak of the ‘QX’ parasite Martelia sydneyi was detected in oysters in the major growing area, the Hawkesbury River near Sydney. This disease has been known in oysters for more than 20 years, but this recent outbreak has resulted in the closure of the Hawkesbury to commercial oyster production.
The Australian aquaculture industry is small by global standards, contributing less than 0.1 per cent of global production by volume (ABARE 2005). The industry is expected to continue to grow at a rapid rate (Love and Langenkamp 2003). It is likely that, at least in some areas of Australia, growth in the industry will be heavily based on sea-cage and other in-water operations, and will place an increasing stress on coastal planning and management as the economic pressure for multiple uses of protected shallow coastal sites of high water quality intensifies. With some exceptions, local, state and national planning processes are presently inadequate to cope responsibly with the demands for aquaculture sites and operations. Better planning and management will be needed to avoid irreversible environmental impacts
Oil and gas
Australia’s oil and gas industry is based around three major production areas: the North West Shelf, Gippsland and Bass Strait, and the Cooper Basin (APPEA, 2003). Australian production is valued at about $15 billion per year.
Each year the industry has several hundred minor incidents (APPEA 2003), but there is also an increased risk of pollution from drilling muds or formation water, from shipping accidents, and the possibility of oil rig or wellhead failure that could result in major spills of oil or gas. At least three areas of importance to whales, in Victoria and Western Australia, are shared with oil and gas wells; increasing the risk of collision, entanglement, and exposure to low levels of contaminants. Most of Australia’s oil and gas wells occur in areas where there are high numbers of threatened species , especially in the north and central west, eastern South Australia and the Bass Strait.
The most important environmental risk is from the shipping of oil and gas products, and the potential for shipping accidents, or accidents related to floating production systems. Where facilities are located in shallow waters, or near sensitive habitats such as coral reefs or seagrass beds, or near habitats of protected species, there are always concerns about possible impacts from accidents. These risks are increasing because of the increased frequency and severity of storms and extreme ocean conditions, which increase the risk of equipment failure and other forms of accidents. The industry has developed extensive environmental programmes to avoid potential impacts. These programmes are supported by a range of research projects that are designed to better understand the current levels of impact and the levels of environmental risk (APPEA 2003).
Shipping
In 2002–03, almost 9000 voyages by ships transported 592 million tonnes of cargo from overseas to Australian ports over the main Coral Sea and west coast shipping lanes. There is also considerable coastal transport of cargo, although only three ports have facilities to handle contaminated ballast water. The increasing number of shipping movements is increasing the risk of collision with cetaceans and other large marine species in estuaries, coastal and ocean waters. In Queensland in 2002, 65 turtles and seven dugongs are considered to have been killed by vessel strikes . There have been no major shipping accidents in Australian waters that have resulted in major oil spills since 1999, when the Laura D’Amato released 250 tonnes of oil in Sydney. In contrast, there have been many small spills and discharges from ships (129 in 2003–04), and a large number (135) of unknown origin (but many likely to be from shipping). Oil spills from any source are dealt with under the provisions of a national plan that provides detailed guidance and methods for coordination in the event of a major spill, training, oil spill cleanup procedures, and equipment that is available at all major ports. Individual ports across Australia also have a range of equipment and local procedures in place in the event of oil spills in their area.
Antifouling paints have previously been a major issue in Australian waters. The most toxic forms (tributyly tin-based paints) have been progressively phased out of use for small vessels. The remaining use of tributyl tin paints is restricted to large commercial vessels, and the main issues of antifouling now are constrained to commercial shipyards and anchorages where there is a high density of these large commercial vessels.
Invasive species
At any given moment, about 10 000 different species are being moved between various regions around the world in the ballast water tanks of the world’s vessels (Carlton 1999). Travel times between Australian and overseas ports are reducing, and there is a greater range of ports that trade directly with Australia. Also, there is an accelerating increase in small vessels (semi-commercial and recreational) travelling between Australia and adjacent countries. Between 150 and 200 million tonnes of ballast water from overseas locations are discharged inside Australia’s territorial seas each year.
More than 250 introduced marine species , and possibly up to about 500 species (Hayes et al 2005), are now established in Australian waters. Such exotic species can have major impacts, and their effects are probably irreversible. For example, the introduced seaweed Undaria pinnatifida, can invade large areas of native, subtidal kelp forests to establish populations at the expense of native species (Valentine and Johnson 2004). Detailed surveys of benthic fauna have discovered that introduced species can be the dominant species (for example, Hutchings et al. 1993), and even in World Heritage Areas, there are substantial populations of introduced marine invertebrates (Wyatt et al. 2005). There are 58 species of marine invaders in Tasmanian waters and, as a result, ballast water from Tasmania is not allowed to be discharged in New Zealand, or in the Port of Hastings (Victoria) (Tasmanian Government, 2003). In response to these issues, Australia has been a leader in the drafting and support for the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and it is the first country to notify its intention to sign the Convention. Compliance with Australia’s mandatory ballast water management requirements by arriving vessels is better than 99 per cent, and it is expected that this reduces the risk of further marine species introductions.
Within Australia, an Intergovernmental Agreement on a National System for the Prevention and Management of Marine Pest Incursions (DAFF, 2005) is being developed to implement a national system for management of ballast water issues and all other vectors, and to provide for emergency response and long-term control and management of species of concern. Emergency response arrangements are in place to deal with major outbreaks of marine invaders (DAFF, 2006). The National Strategy does not yet incorporate a comprehensive system for monitoring of ports or adjacent areas to detect introduced species that may have important ecological consequences (as opposed to commercial consequences), and this may allow invasive species to pass unnoticed until they are well entrenched into local ecosystems, possibly with irreversible ecological impacts. Nonetheless, the high level of cooperation between state, territory and Commonwealth agencies demonstrates the importance of the issue of marine invasive species, and the commitment of governments to identify and address such a key issue for Australia’s marine industries and biodiversity.
Tourism and recreation
Australians and visitors to Australia admire the high quality of coastal and ocean ecosystems across much of the continent, especially away from the urban centres. The diversity and naturalness of coastal and marine recreational attractions is, to some extent, taken for granted by Australians, however well established and enshrined it is into the national culture. In 2004, domestic and international visitors spent about $20 billion purely on recreational and tourist activities directly involving coastal and ocean ecosystems.
The popularity of all nature-based tourism, including whale watching, diving, snorkelling, glass-bottom boat tours and sea kayaking, is rapidly increasing in Australia. In the Ningaloo Marine Park (Western Australia), swimming with whale sharks has grown into a $12 million a year industry in little more than a decade, attracting visitors from around the world (DCLM 2005).
The success of tourism and recreation, in both monetary and visitor enjoyment terms, is dependent on the availability of the resource and there being appropriate infrastructure and facilities. Maintaining the naturalness of the ecosystems, including their biodiversity, is clearly an essential objective of planning for recreation and tourism; but there is no national, integrated system for assessing or reporting on the performance of tourism ventures in relation to their ecosystem resource base.
Coastal development
Coastal strip development through incremental extension of most of Australia’s existing urban areas threatens much of the temperate coast and tropical systems near existing centres of population. This leads to pressure for opening and dredging of estuary and lagoon channels, construction of marinas, beach groynes, and coastal stabilisation projects, all of which gradually degrade coastal habitats and ecosystem functions. These pressures are accelerating because of the increasing coastal focus of Australia’s population, the increasing vehicle mobility and access to coastal areas and coastal waters, exposure of acid-sulphate soils during development. and the ongoing demand for tourism and recreation facilities to cater for non-consumptive uses of coastal and marine ecosystems.
The cumulative outcomes of such ongoing coastal alienation of habitat, the alteration in natural dynamics and hydrological cycles in coastal wetlands, and the pressure on fish and coastal invertebrates, results in an ongoing series of complex changes to coastal ecosystems. For example, foreshore lands are rapidly being developed for urban dwellings near Mandurah, Western Australia (Figure 5). This urban expansion is linked with the unsuccessful attempt to resolve the eutrophication problem of the Peel Harvey estuary in the late 1990s, in which a canal was dredged in an attempt to flush nutrients from the estuary, and to reduce algal blooms that resulted from the high levels of nutrients in agricultural runoff. Associated with this has been development of surrounding housing estates, recreation areas and coastal access roads. The direct and indirect impact of this $50 million engineering initiative extends along the coast north and south of the canal, including changes to local groundwater and wetland systems. In 2003, a $2 million Commonwealth-State water quality improvement programme was announced, with the aim of improving water quality in the estuary. Although there are now indications of improvements in water quality near the canal from the increased flushing by marine water, elsewhere in the estuary there are apparent increases in harmful algal blooms, bank erosion, low oxygen events and large ‘dead zones’ (DEH, 2003).
