Marine environment

Values of our marine environment

Australians have a love affair with the beach and the coast, reflected in our coastal settlement, our recreation, arts and culture.

The diversity of three oceans, five climate zones, varied underwater seascapes and mighty currents bring together a trove of ocean treasures. With a coastline stretching 70,000 kilometres, Australia has the greatest diversity of marine species and habitats of any single nation.

The Global Census of Marine Life ranks Australia number one for marine biodiversity, with more species recorded than any other country. Thirty-three thousand marine species are known to occur in Australian waters, including 8525 molluscs, 6365 crustaceans and 5184 fishes (20 per cent of the total global number of fish species). Importantly, many of these species are found only in Australia – for instance, up to 80 per cent of the fish on our temperate coasts are unique to our nation. The seabed with its shallow waters, continental shelves, slopes, plateaus and abyssal plains provides a wide range of habitats for plants and animals. These seabed habitats are also important in supporting ocean productivity. For instance, upwellings of nutrient-rich waters around undersea canyons support biodiversity hotspots where high numbers of feeding seabirds, whales and dolpins are present.

One of Australia’s most remarkable natural gifts, the Great Barrier Reef is the world’s largest coral reef. It has an abundance of marine life and comprises over 3000 individual reef systems and coral cays and hundreds of picturesque tropical islands.

Australia’s east and west coasts are migration routes for a range of threatened species. For example, the line of shelf-canyons on the west coast of Australia is a ‘whale highway’, where thousands of humpback whales travel annually on their migration from their Antarctic feeding grounds to their breeding grounds in northern Australia and back again. Marine parks are the backbone of biodiversity protection. However, less than 5 per cent of the Australian marine environment is in fully protected marine sanctuaries (where mining and fishing are prohibited), compared with more than 10 per cent of our land area. This falls well short of the 20 to 50 per cent recommended internationally for long-term ocean health. Marine-based industry contributes about 4 per cent of Australia’s GDP and is increasing rapidly. Industries include:

  • energy production (oil and gas extraction).
  • fishing and aquaculture.
  • recreation and tourism.
  • emerging industries such as seabed mining, carbon capture, desalination, tidal and wave power, and the use of marine organisms for new materials or pharmaceuticals.

Our marine economy supports thousands of jobs, but the oceans also provide $25 billion every year in services including:

  • carbon storage at about $15.8 billion a year. Seagrasses store 10 to 40 times as much carbon per hectare as forests. Australia’s seagrass meadows are the largest in the world.
  • fish nursery services, pest and disease control – $6.2 billion. These are crucial for our commercial fishing industry.

And finally, healthy oceans are essential to life on our planet. According to some estimates, green algae and cyanobacteria provide 20 per cent of the oxygen produced on Earth.

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