East-Central Australian Shelf large marine ecosystem

Source: NOAA

Introduction

caption Location of the East-Central Australian Shelf Large Marine Ecosystem (Source: NOAA)

The East-Central Australia Large Marine Ecosystem (LME) extends from the edge of the Great Barrier Reef in Queensland to the approximate latitude of Cape Howe, at the southern end of the state of New South Wales. It is characterized by a narrow continental shelf that is bordered by the Tasman abyssal plain. The South Equatorial Current from the Pacific Ocean gyre flows westward towards the Australian coast and bends south (left) under the influence of the Coriolis effect to become the East Australian Current. The climate is temperate.

Productivity

The East Australian Shelf LME is considered a Class II, moderately high (150-300 grams of carbon per square meter per year) productivity ecosystem based on SeaWiFS global primary productivity estimates. At this latitude, water temperature, levels of wind mixing and inputs of light necessary for photosynthesis go through seasonal cycles. During the winter, strong winds and cool surface water temperatures enhance vertical mixing processes, breaking down vertical density gradients and allowing nutrient-rich waters to mix into the surface layer. However, the overall productivity of this temperate Australian LME is restricted by the poleward transport of low-nutrient tropical waters along the continent's eastern margin by the East Australian Current. There are no large seasonal blooms producing surpluses of organic matter. As a result, Australia lacks the large demersal fisheries that characterize northern hemisphere continental shelf systems. For a general understanding of oceanographic processes affecting the nutrient dynamics and productivity of Australian marine ecosystems, see the State of the Environment Report. For more information on productivity, see Furnas. For information on ocean surface environmental data (currents, temperatures, winds), see CSIRO.

Fish and Fisheries

caption LME: East-Central Australian Shelf (Source: NOAA)

Australian waters are relatively nutrient-poor and unable to sustain large fish populations. The LME has a very narrow continental shelf. Production is limited by nutrient runoff and low levels of nutrient-rich upwellings. Fish stocks in the East-Central Australia LME are quite small. Some species are endemic to Australia. Until recently, fisheries resources were usually managed in separate fishery units. Under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act), the Commonwealth Government now has a framework that helps it to respond effectively to current and emerging environmental problems, and to ensure that any harvesting of marine species is managed for ecological sustainability. New South Wales Fisheries is the principal agency responsible for conserving the aquatic environment and managing the fisheries resources of this LME. It is responsible for protecting and restoring fish habitats, promoting responsible and viable commercial fishing, and supporting aquaculture industries. For information on South-East Fisheries (SEF), see CSIRO. Two of the more significant commercial fisheries are the estuary prawn trawl fishery, squid, and the East Coast tuna fishery. The Food and Agriculture Organization (FAO) provides information on Australia’s fisheries and the characteristics of the industry. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME.

Pollution and Ecosystem Health

The LME is threatened by an increase in shipping. It is also the site of some of Australia’s largest cities and ports such as Sydney. Ships entering ports empty of cargo are ballasted with water collected in the last port of call. This ballast water has been shown to contain organisms including bacteria, viruses, algal cells, plankton, and the larval forms of many invertebrates and fish. There is direct physical damage caused by port and industrial development, pipelines, mining and dredging. There are also environmental impacts caused by tourism, and by the provision of infrastructure to support tourism (airports, power generation facilities, accommodation, sewage treatment and disposal facilities, moorings, and marine transport). For more information on coastal and marine pollution issues in this LME, see Environment Australia, one on pollution, and the State of the Environment Report

Socioeconomics

Thousands are involved in the fisheries, aquaculture and processing sectors of the economy. FAO provides information on the characteristics and socioeconomic benefits of Australia’s fishing industry. The LME contains a number of major cities and ports, including Sydney and Port Jackson, Australia’s largest port. Industry, shipping and tourism are major economic activities. Sydney Harbor and the city are internationally recognized. Marine and coastal-based tourism is important in this LME both in terms of domestic and international tourism. A significant proportion of the Australian population is involved in recreational fishing, diving, snorkeling, and boating. Tourists from overseas prize an unspoiled marine environment. There are, however, social, cultural, economic and environmental impacts caused by tourism. Tourism may affect the lifestyle of residents in ways they perceive as intrusive. Negative social impacts may include real or perceived increases in crowding, prices, or crime, as well as increase conflict between commercial, recreational and indigenous interests.

Governance

The East-Central Australia LME lies off the coast of the state of New South Wales. Some governance issues in this LME pertain to fisheries management and to the establishment of marine reserves (including Booderee National Park and Botanic Gardens). Australian fisheries resources are managed under both Commonwealth and State/Territory legislation. The demarcation of jurisdiction and responsibilities among these various governments has been agreed to under the Offshore Constitutional Settlement (OCS). Under OCS, the states and territories have jurisdiction over localized, inshore fisheries. The Commonwealth has jurisdiction over offshore fisheries or fisheries extending to waters adjacent to more than one state or territory. Each government has separate fisheries legislation and differing objectives. Transboundary fisheries and foreign fisheries are managed by the Commonwealth fishery agencies. An important goal is to ensure that the exploitation of fisheries resources is conducted in a manner consistent with the principles of ecologically sustainable development. This includes the need to assess the impact of fishing activities on non-target species and the long-term sustainability of the marine environment. For more information on the governance of Australia’s fisheries, see the FAO website. Reserves have been declared to help protect rocky shore habitats and marine life, provide opportunities for research and education, conserve Australia’s cultural heritage and help boost ecotourism. In 2001, the Government held a consultation process that indicated there was strong community support to further protect these aquatic reserves. The marine tourism industry has produced a code of conduct that covers issues such as anchoring, removal of rubbish, fish feeding and preservation of world heritage values. Australia declared a 200 nautical-mile Exclusive Economic Zone in 1978. Australia is party to the following international agreements: Antarctic-Environmental Protocol, Antarctic Treaty, Biodiversity, Climate Change, Endangered Species, Environmental Modification, Hazardous Wastes, Law of the Sea, Marine Dumping, Marine Life Conservation, Nuclear Test Ban, Ozone Layer Protection, Ship Pollution, Tropical Timber 83, Wetlands, and Whaling.

References

Articles and LME Volumes

  • Morgan, J., 1989. Large Marine Ecosystems in the Pacific Ocean. In: Biomass Yields and Geography of Large Marine Ecosystems, K. Sherman and L.M. Alexander, eds. AAAS Selected Symposium, 377-394. ISBN: 0813378443.

Other References



Disclaimer: This article is taken wholly from, or contains information that was originally published by, the National Oceanic and Atmospheric Administration (NOAA). Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the National Oceanic and Atmospheric Administration (NOAA) should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.

Glossary

Citation

(2008). East-Central Australian Shelf large marine ecosystem. Retrieved from http://www.eoearth.org/view/article/51cbed737896bb431f6923d2

0 Comments

To add a comment, please Log In.