Dugongs

Threatened Status:

  • Listed as ‘Vulnerable’ globally (IUCN Red List)
  • Protected Marine and Migratory Species in Australia (EPBC Act)
  • Listed as ‘Vulnerable’ in Queensland (Nature Conservation Act)
  • Listed as Other protected fauna in WA (Biodiversity Conservation Act)

Location:

  • Throughout northern Australia from Shark Bay, WA, to Moreton Bay in Queensland. 

Dugongs are shy, elusive marine mammals that depend on healthy seagrass meadows for their diet.

Dugong populations have declined around the world, due to a range of threats. Australia is home to globally significant and some of the last healthy populations of dugongs. We have a global obligation to conserve and recover this species for future generations.

About Dugongs

  • Australia is home to the world’s largest dugong population with more than 100,000 thought to live in the Torres Strait.
  • Dugongs diet consists almost entirely of seagrass.
  • Dugongs can live for around 70 years, but they are slow to mature, with females reaching breeding age at around 10 years.
  • Females only give birth to a single calf every 3-7 years. The calf will stay with its mother for two years.
  • If there are stresses in their environment (such as increased cyclones and floods from climate change) then dugongs will produce fewer young.
  • Dugongs have the ability to hold their breath for up to 11 minutes and dive up to 33 metres.
  • Dugongs grow up to 3 metres in length and weigh over 500 kilograms.
  • Dugongs restore and spread seagrass habitats, making them essential ecosystem engineers. Seeds digested by dugongs are spread further and germinate much faster when transported by the dugong and its poop!

 

Threats to Dugongs

While some of Australia’s dugong populations are healthy, others, such as on the Southern Great Barrier Reef, are in decline.

Commercial gillnet fishing is a major threat to dugongs in Queensland. Dugongs are air breathing marine mammals, and are easily entangled in fishing nets and drown.

Some areas along the eastern Queensland coastline are closed to fishing to protect dugongs and other marine wildlife, but we need more net free zones in our Great Barrier Reef to ensure their recovery.
Dugongs are also threatened by climate change and poor water quality. Dugongs are dependent on shallow coastal waters and are vulnerable to rising sea levels and extreme weather events, such as cyclones, flooding and water pollution, which destroy their critical seagrass meadows.

Collisions with boats are another threat to dugongs, go-slow zones in key habitats are needed to reduce this risk.

References

  1. Department of Agriculture, Water and the Environment (2021) ‘Dugong’ Available at https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=28
  2. Queensland Government (2021) ‘Nature Conservation Act 1992’ Available at https://www.legislation.qld.gov.au/view/html/inforce/current/act-1992-020
  3. Marsh H, Sobtzick S (2019) Dugong Dugon. The IUCN Red List of Threatened Species 2019. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T6909A160756767.en.
  4. Department of Agriculture Water and the Environment (n.d.) ‘Dugongs’ Available at https://www.environment.gov.au/marine/marine-species/dugongs
  5. Great Barrier Reef Marine Park Authority (n.d.) ‘Dugong’ Available at https://www.gbrmpa.gov.au/the-reef/animals/dugong
  6. ABC, 2021. “Scientists discover seagrass grows better after its seeds have been eaten by dugongs, turtles”

Dive Further