The dugong is one of the most improbable-looking creatures in the ocean. A large, slow-moving marine mammal shaped roughly like a barrel with flippers, it spends its days grazing on seagrass meadows in shallow coastal waters. It’s the only strictly herbivorous marine mammal. It can live for 70 years. It’s closely related to elephants. And Australia is home to the majority of the world’s remaining dugong population.

That population is in trouble. Not dramatic, headline-making trouble - dugongs aren’t going to go extinct next year. But the long, slow decline that characterises many marine species is well underway, and the trajectory is concerning.

Australia’s Dugong Population

Australia’s dugong population is estimated at approximately 80,000 individuals, the vast majority found in the waters of Queensland, the Northern Territory, and Western Australia. The largest concentrations occur in the Great Barrier Reef Marine Park, Torres Strait, Moreton Bay, Shark Bay in Western Australia, and the coastline of the Northern Territory.

These numbers sound healthy, and in a global context they are - Australia has more dugongs than any other country by a wide margin. But the trend matters more than the absolute number, and the trend in several key populations is downward.

Aerial surveys conducted by James Cook University researchers over the past three decades show significant declines in some regions. The urban coast of Queensland (from Cooktown south to the Gold Coast) has seen dugong numbers decline by an estimated 50-70% since the 1980s. Even in relatively pristine areas like the Torres Strait and far northern Great Barrier Reef, populations have shown periods of decline, often following extreme weather events that damaged seagrass habitat.

The southern Great Barrier Reef region, which includes the waters around Gladstone, Mackay, and the Whitsundays, has experienced particularly sharp declines. This region has been affected by multiple cyclones, flooding events, and port development activities that have degraded seagrass habitat.

The Seagrass Problem

Everything about dugong conservation comes back to seagrass. Dugongs eat seagrass. That’s essentially all they eat. An adult dugong consumes approximately 30-40 kilograms of seagrass per day, spending most of its waking hours grazing.

This dietary specialisation means that dugong populations are completely dependent on the health of seagrass meadows. When seagrass is abundant and healthy, dugongs thrive. When seagrass declines, dugongs decline - directly, through starvation and reduced reproductive success, and indirectly, through displacement to less suitable habitat.

Australian seagrass meadows have been under sustained pressure. The major threats include:

Coastal development. Port expansions, dredging, and urban development disturb sediment, increase turbidity, and physically destroy seagrass beds. The development of ports at Gladstone, Abbot Point, and Townsville has directly impacted seagrass habitat in the central Great Barrier Reef region.

Agricultural runoff. Sediment, nutrients, and pesticides from farming operations (particularly sugarcane and cattle grazing in Queensland) flow into coastal waters via rivers. Elevated nutrient levels promote algal growth that smothers seagrass. Increased sediment reduces the light that reaches the seabed, limiting photosynthesis. Research by CSIRO has documented clear links between river discharge events and seagrass decline in the Great Barrier Reef lagoon.

Extreme weather. Cyclones physically tear up seagrass beds, and the flooding that follows cyclones delivers massive pulses of freshwater, sediment, and nutrients to coastal areas. Tropical Cyclone Yasi (2011) and the associated flooding destroyed extensive seagrass beds in the central Great Barrier Reef, triggering a dugong mortality event as animals starved or were forced to travel long distances to find food.

Climate change. Rising sea temperatures are affecting seagrass species composition and distribution. Marine heatwaves, like the one that devastated Shark Bay’s seagrass in 2011, can cause rapid die-offs. The Shark Bay event killed approximately 36% of the seagrass meadow, which in turn led to documented dugong mortality and displacement.

Other Threats

While seagrass loss is the primary driver of dugong decline, several other factors compound the problem.

Boat strikes kill dugongs in areas with heavy boat traffic. Dugongs are slow swimmers that feed in shallow waters often used by recreational and commercial vessels. In Moreton Bay (adjacent to Brisbane), boat strikes are one of the leading identified causes of dugong mortality. As coastal populations grow and boat traffic increases, this problem is worsening.

Gill nets and shark nets entangle dugongs. Incidental catch in commercial and recreational gill nets has been documented in multiple fisheries. Queensland’s shark control program, which deploys nets and drumlines at popular swimming beaches, also catches dugongs - an estimated 5-10 per year in recent reporting periods. The animals can drown if unable to reach the surface to breathe.

Indigenous harvest. Dugong hunting is a legally recognised right for Aboriginal and Torres Strait Islander peoples in Australia, and it holds deep cultural and nutritional significance. The harvest is managed through community-based management plans, but in some regions, combined pressure from hunting and habitat loss has raised questions about sustainability. This is a politically and culturally sensitive issue, and any discussion of it must acknowledge the importance of customary rights alongside conservation concerns.

What’s Being Done

Conservation efforts for dugongs in Australia operate across multiple scales.

The Great Barrier Reef Marine Park zoning plan protects significant areas of dugong habitat from fishing, trawling, and other extractive activities. Dugong Protection Areas (DPAs) restrict the use of gill nets in key habitats along the Queensland coast.

The Reef 2050 Long-Term Sustainability Plan includes targets for improving water quality in the Great Barrier Reef catchment, which directly benefits seagrass. Progress has been slow - reducing agricultural runoff requires changing farming practices across a vast catchment - but measurable improvements have been documented in some rivers.

Seagrass restoration research is advancing. Several Australian research groups are trialling methods for seagrass transplantation and seed-based restoration in degraded areas. These efforts are still small-scale relative to the areas of seagrass loss, but they demonstrate that recovery is possible under the right conditions.

Community-based monitoring programs, including the Seagrass-Watch network, engage citizen scientists and Indigenous ranger groups in tracking seagrass condition across northern Australia. This monitoring provides early warning of seagrass decline and helps target management interventions.

Go-slow zones for boats in key dugong habitats reduce the risk of vessel strikes. Moreton Bay, in particular, has implemented speed restrictions in areas identified as high-risk for dugong-boat interactions.

The Outlook

Dugong conservation in Australia is a long game. These are slow-breeding animals (females produce one calf every 3-7 years) in a rapidly changing environment. Population recovery, even under ideal conditions, takes decades.

The critical variable is seagrass. If seagrass meadows can be maintained and restored, dugong populations have a reasonable chance of stabilising and eventually recovering. If seagrass continues to decline - driven by climate change, poor water quality, and coastal development - dugong populations will continue to decline with it.

The connection is that direct. Protecting dugongs means protecting their habitat, which means addressing water quality, coastal development impacts, and ultimately, climate change. There are no shortcuts, and no amount of direct protection of individual animals will compensate for the loss of the ecosystem they depend on.

Australia has a unique responsibility here. We hold the majority of the world’s dugongs in our waters. How we manage our coasts, our catchments, and our climate response in the coming decades will determine whether this species has a future. The science is clear about what needs to happen. Whether we do it is a question of political will and public priority.