Shellfish Reefs


  • Recently a study led by the Nature Conservancy found that between 90 and 99 % of Australia’s shellfish reefs have vanished since British colonisation 230 years ago.
  • The reefs, formed by millions of oysters or mussels clustering together.
  • These are used to occur in bays, estuaries and nearshore coastal waters in both tropical and temperate regions across every State in Australia.
  • Working just like coral reefs, they support the growth of important fish species whilst also helping to improve water quality and increase biodiversity.
  • Scientists said their degradation contributed to the-
    (a) The release of stored carbon
    (b) Worsening climate change
    (c) Increasing coastal risks associated with more frequent and intense storms
    (d) Sea level rise
    (e) Ocean Acidification etc.

About Coral reefs:

  • The Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria.
  • They typically live in compact colonies of many identical individual polyps.
  • The Coral reefs are built by and made up of thousands of tiny animals—coral “polyps”—that are related to anemones and jellyfish.

About Coral bleaching:

  • The Coral bleaching occurs when coral polyps expel algae that live in their tissues.
  • Normally, coral polyps live in an endosymbiotic relationship with the algae and that relationship is crucial for the coral and hence for the health of the whole reef.
  • Bleached corals continue to live. But as the algae provide the coral with 90% of its energy, after expelling the algae the coral begins to starve.
  • Above-average sea water temperatures caused by global warming have been identified as a leading cause of coral bleaching worldwide.


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