Dugong

The dugong (Dugong dugon) is the only plant-eating mammal that lives its entire life in the marine environment. Often called sea cows, these shy, slow-moving creatures spend most of their day feeding on seagrass. Interestingly, dugongs and their relatives are more closely related to elephants than any other marine mammal. These fascinating sea mammals leave tell-tale feeding trails through the seagrass beds found throughout the shallow banks of Moreton Bay Marine Park.

Read more about the behaviour and ecology of dugongs.

The slow breeding rate means that dugongs are particularly susceptible to factors that threaten their survival. Dugongare listed as a vulnerable species under the Nature Conservation Act 1992 and are protected as a ‘marine’ and ‘migratory species’ under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999.

Moreton Bay dugongs are different

Dugongs are generally found in coastal waters such as shallow, calm, wide protected bays but can also be spotted in estuarine creeks, streams and offshore waters. Their distribution stretches from Shark Bay in Western Australia, over the northern coastline and down the Queensland coast. Moreton Bay Marine Park is the southern limit of dugong along the east coast of Australia. Moreton Bay Marine Park is the only place in the world where dugong are found close to a major capital city.

The marine park is home to about 600-800 of these gentle sea creatures. Moreton Bay's dugongs are not completely herbivorous, as was commonly thought. Research shows that they supplement their seagrass diet with macro-invertebrates, such as ascidians (or sea squirts).

Once found throughout the marine park, dugongs are now mostly found on the Moreton and Amity banks, however some are found in Pumicestone Passage and the southern bay. Usually seen singly or in pairs elsewhere, Moreton Bay Marine Park's dugong are commonly found in herds of about 100 animals. Dugong can travel long distances, with Moreton Bay's dugong travelling as far as Hervey Bay, 200km north.

Exploitation of dugong

Herds of dugongs were once observed in incredible numbers in the mid-1800s in the Moreton Bay area. In the 1850s, Europeans began to hunt dugongs for their flesh and oil to export to Europe for medicinal purposes. The oil soon became so popular that demand from England and Europe far exceeded the supply. This demand pressure affected quality control causing irregularities in preparation, inferior quality of the product and uncertain supply. As a result, trade with Europe ceased and fishing stations were shut down in the latter half of the 1800s.

Over the years, various regulations have been implemented to manage dugong hunting. There have been licence requirements to hunt dugong, introduction of short-term closures, rules on what fishing equipment could be used, when they could be fished, and requirements for disposal of flesh and offal. On 20 March 1969, the fisheries department introduced a total prohibition on the taking of dugong in Moreton Bay. Under the Native Title Act 1993 traditional hunting of dugong is allowed for non-commercial purposes. Guidelines for administering traditional hunting activities in Moreton Bay Marine Park have been implemented.

Protecting dugongs from threats

The main threats to dugongs include vessel strike and diminished food availability, e.g. following extreme weather events such as floods.

In the Moreton Bay Marine Park, dugong are particularly susceptible to boat strike. Going slow for those below is a legal requirement in designated go slow areas in the marine park which are established to protect dugongs from injury, disturbance or death caused by boat strike, especially in critical feeding and resting areas. To know where you need to go slow, download the Marine Parks Southern QLD phone app.

The dugongs in Moreton Bay Marine Park also face the threat of diminishing food sources. Seagrass meadows, the primary food source for dugong, once occurred close to Brisbane's shoreline but pollution, algal blooms, high boat traffic and turbid waters have reduced their distribution. Today, dugong need to rely on smaller seagrass meadows for food and habitat. When the seagrass habitat becomes unsuitable for foraging, dugong populations are displaced and placed under greater threat.

Protection of seagrass habitat in the marine park is achieved through specific zoning measures, which prohibit certain fishing activities like trawling.

Further reading

Daley, B., Griggs, P. and Marsh, H. (2008). Exploiting marine wildlife in Queensland: the commercial dugong and marine turtle fisheries, 1847-1969. Australian Economic History Review 48 (3): 227-265.

Lanyon, J.M. (2019). Chapter 6 - Management of Megafauna in Estuaries and Coastal Waters: Moreton Bay as a Case Study. In Wolanski, E., Day, J.W., Elliott, M. and Ramachandran, R. (Eds.) Coasts and Estuaries (pp. 87-101). Elsevier. https://doi.org/10.1016/B978-0-12-814003-1.00006-X.

Marsh, H., Blair, D., Cleguer, C., Groom, R., Hodgson, A., Hutton, M., Lanyon, J., McKenzie, L., McNiven, I. and Raudino, H. (2025). Chapter 10 - Australia. In Marsh, H., Loates, P.J and Schramm, L. (eds.) Global assessment of dugong status and conservation needs. Convention on the Conservation of Migratory Species of Wild Animals (pp. 271-324). CMS Technical Series Publication No. 51. https://doi.org/10.25903/0ncx-v838; ISBN: 978-3-937429-40-3

Sobtzick, S., Cleguer, C., Hagihara, R., and Marsh, H. (2017). Distribution and abundance of dugong and large marine turtles in Moreton Bay, Hervey Bay and the southern Great Barrier Reef. A report to the Great Barrier Reef Marine Park Authority.