Dugong conservation status

Worldwide, the dugong is listed under the IUCN - the World Conservation Union - Red List of Threatened Animals as being vulnerable to extinction - criteria A1cd.

In Australia, dugongs are protected under various legislation. They are not presently listed as threatened under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999, however, they are protected because they are a ‘listed migratory’ and a ‘listed marine’ species. They are also protected by other Commonwealth legislation such as the Great Barrier Reef Marine Park Act 1975 where they are a protected species. The Queensland Government's Nature Conservation Act 1992 lists dugongs as 'vulnerable to extinction'.

The IUCN and Australian listings reflect, while dugongs are threatened on a worldwide scale, Australia has a large proportion of the remaining population. This makes Australia the largest, and globally most important, refuge for dugongs. The sensitive ecological status of these animals globally highlights the need for effective management strategies to protect and conserve the Australian population.

A) Status of dugongs along the urban coast of the Great Barrier Reef

Numbers have declined dramatically in recent years along the urban coast of the Great Barrier Reef World Heritage Area south of Cooktown and the species is facing the threat of disappearing from the area. The Great Barrier Reef Ministerial Council is concerned about the decline and has instigated a number of actions to reverse the trend. Government departments, Indigenous people, industry organisations, community groups and individuals are working together to reduce the number of dugong deaths from human-related causes to as close to zero as possible.

Declining numbers

• Anecdotal evidence of historical dugong population decline comes from descriptions of ‘… endless herds of dugong’ in Moreton and Hervey Bay published in memoirs during the 1800’s and early 20th century. These herds are now believed to be only a remnant of their former population size.
• Experts consider the decline in dugong numbers is due to unsustainable mortality from human-related causes such as habitat loss or degradation, commercial mesh nets (fish nets), shark nets set for bather protection, unsustainable Indigenous hunting in some areas, boat strikes, Defence activities, and marine debris. It is likely the population in the 1960s was much less than at the time of European settlement as commercial dugong hunting existed at several locations along the Queensland coast between the 1850s and 1960s when dugong were protected in Queensland.
• An analysis of dugongs caught unintentionally in shark nets at bathing beaches suggests the dugong population in urban areas of the Queensland coast declined significantly between 1962 and 1999 and is now only a few per cent of what it was in the early 1960s. This was when the Queensland Shark Control Program commenced (see case study on ‘Shark control records hindcast dramatic decline in the dugong’).
• Aerial surveys commissioned by the Great Barrier Reef Marine Park Authority covered 39 000 square kilometres of the inshore waters of the southern World Heritage Area. These surveys have occurred in 1986–87, 1992, 1994, 1999 and 2005.

The largest and most important remaining concentrations of dugongs in the southern part of the World Heritage Area are in the Cardwell/Hinchinbrook, Cleveland to Upstart Bay, and Shoalwater Bay areas.

B) Status of dugongs in the remote Great Barrier Reef, north of Cooktown

• Although dugong numbers in the remote part of the Great Barrier Reef World Heritage Area, north of Cooktown, showed no significant change in surveys between 1985 and 2000, there is concern that unsustainable numbers are being taken by Indigenous hunters and in commercial fishing nets.

Sustainable loss from human-related causes

The dugong population in the Great Barrier Reef can only cope with a human-caused mortality of less than 1–2 per cent each year. This means that if there are 200 dugongs in a bay, the population can only cope with the loss of two to four dugongs per year from all human causes (i.e. fishing, boat strikes, Indigenous hunting).

The number of dugongs in the Great Barrier Reef north of Cooktown has remained stable since surveys started in 1986. The lines above and below each bar show the standard error, an indication of the uncertainty associated with the measurement

Management requirement

Reduce the loss of dugongs from human-related causes as far as possible.