Dugongs are gentle, slow-moving grazers that spend their lives in shallow coastal water, quietly cropping seagrass. That lifestyle puts them exactly where people fish, build, dredge, drive boats and dump runoff. Add a breeding rate so slow that a dugong population can barely grow a few percent a year even in perfect conditions, and you have an animal that is easy to lose and very hard to bring back. This page explains the main threats, what is known about dugong numbers, how status differs across the range and what is being done to help. For an overview of the species, see our dugong facts page.

Are dugongs endangered?

Globally, the dugong is listed as Vulnerable on the IUCN Red List, one step below Endangered. Regionally, the picture is much worse.

The global Vulnerable listing reflects a species that is still fairly widespread, with large numbers in Australia and the Arabian Gulf, but that has declined or vanished across much of its range. In 2019 the IUCN assessed two regional populations separately for the first time. The East African dugong, found from Mozambique to Kenya and around Madagascar, was listed as Critically Endangered, with perhaps only a few hundred animals left and continuing losses in fishing nets. The New Caledonia population was listed as Endangered, after surveys suggested a decline.

In other places, dugongs have already gone. A 2022 study concluded that dugongs are functionally extinct in China, where no confirmed sightings had been reported by scientists for many years. In Japan, the small group around Okinawa has dwindled to very few animals or possibly none. Many populations in South and Southeast Asia now number in the dozens or low hundreds. So “Vulnerable” is an average that hides a lot of local emergencies.

Threat 1: Drowning in fishing nets

Bycatch is the most widespread threat to dugongs. Like all marine mammals, dugongs breathe air, and when they become tangled in gillnets, they drown within minutes. Gillnets set across shallow bays and channels, exactly where dugongs feed, are especially dangerous. Shark nets set off beaches in parts of Queensland have killed dugongs too, as have shrimp trawls and fish traps in some regions.

In many developing countries, nets are cheap and unregulated, and coastal communities depend on them for food and income. A fisherman who finds a drowned dugong in his net may eat it or sell the meat, which blurs the line between accidental bycatch and hunting. East Africa, South Asia and Southeast Asia have all lost many dugongs this way. In Australia, dugong protection areas restrict netting in key habitats, which has helped.

Threat 2: Loss of seagrass

Dugongs depend on seagrass almost completely, and seagrass meadows are disappearing worldwide. They are lost to dredging, land reclamation, port and resort construction, boat moorings and propeller scars. Even more damaging is runoff: sediment and nutrients from farms, cleared land and cities cloud the water and block the sunlight seagrass needs to photosynthesise, or fuel algae that smother it.

Extreme weather can wipe out seagrass on a huge scale. In 2011, floods and Cyclone Yasi destroyed large areas of seagrass along the Queensland coast, and hundreds of dugongs died or stranded in the following months, many of them emaciated. The same year, a marine heatwave in Western Australia killed a large share of the seagrass in Shark Bay, one of the dugong’s great strongholds, and dugong numbers there dropped as animals died or left. As oceans warm, these events are expected to become more frequent. For how much dugongs depend on these meadows, see what do dugongs eat.

Threat 3: Hunting

People have hunted dugongs for thousands of years for meat, oil, skin, bones and teeth. In parts of Asia and the Pacific, dugong products were also used in traditional medicine. Commercial hunting in the 19th and early 20th centuries wiped out or severely reduced many populations, including along the Queensland coast, where dugong oil was once sold as a health tonic.

Today, hunting is illegal in most range countries, but illegal hunting persists in some places. In Australia and Torres Strait, Aboriginal and Torres Strait Islander people have legal rights to hunt dugongs as part of their culture, and many communities now manage their own hunting through agreements and plans designed to keep harvests sustainable. The challenge is that a slow-breeding animal can only sustain a very small harvest, so the combination of hunting, bycatch and habitat loss can tip a population into decline.

Threat 4: Boat strikes, noise and pollution

Dugongs spend much of their time near the surface in shallow water, so fast boats can hit them, especially in busy harbours and recreational boating areas such as Moreton Bay near Brisbane. Boat traffic and coastal construction also create noise that can disturb feeding and drive dugongs away from important seagrass areas. Chemical pollution, including heavy metals and pesticides, has been found in dugong tissues, though its effects are less understood than those of nets and habitat loss. Plastic and lost fishing gear add to the entanglement risk.

Why slow breeding makes it worse

The real reason dugongs are so vulnerable is their life history. Dugongs can live for around 70 years, but they are slow to start breeding. Females typically have their first calf somewhere between about 6 and 17 years of age, and the age varies with food supply. Pregnancy lasts roughly 13 to 14 months, and a single calf is born. The calf stays with its mother for around 18 months or more, and the gap between calves is usually 2.5 to 7 years, longer when seagrass is scarce.

The result is that even a perfectly healthy dugong population can only grow by a few percent a year at best. Scientists have calculated that losing more than a very small fraction of adult females each year, from any cause, is enough to send a population into decline. When food is short after a cyclone or heatwave, females may stop breeding altogether for years. That is why a few extra deaths from nets or boats, which might hardly matter for a fast-breeding fish, can be devastating for dugongs.

Dugong population: how many are left?

Nobody knows the exact global dugong population, because many populations have never been properly surveyed and dugongs are hard to count. Most estimates come from aerial surveys, where observers fly transects over seagrass areas and count the animals they see, then correct for those underwater or in murky water.

What is clear is that most of the world’s dugongs live in northern Australia, where populations in Torres Strait, along the Great Barrier Reef coast and in Shark Bay number in the thousands to tens of thousands. The Arabian Gulf holds the second-largest population, estimated at several thousand animals. Elsewhere, numbers are typically small: tens to a few hundred in many countries of East Africa, South Asia and Southeast Asia. For a region-by-region look at where they still live, see where do dugongs live.

What is being done to protect dugongs

Dugongs are protected by law in most countries where they occur, and they are listed under CITES, which bans international trade in dugong products. An international agreement under the Convention on Migratory Species, the Dugong Memorandum of Understanding, brings range countries together to coordinate research and conservation.

On the ground, the most effective measures are protecting seagrass and reducing deaths in nets. That includes dugong protection areas and marine parks where gillnets are restricted, community-run programs that pay or support fishermen to release entangled dugongs and switch to safer gear, go-slow boating zones in busy areas, and controls on dredging and land clearing to reduce runoff. In Australia, Indigenous ranger programs monitor dugongs and seagrass and manage traditional hunting. Seagrass restoration projects, though still small in scale, are also being tested in several countries.

Dugongs are close cousins of manatees, and the threats facing them will sound familiar to anyone who follows manatee conservation. Our dugong vs manatee page compares the two.

What my years under reef lights taught me about seagrass

I’ve kept reef systems since 1996, and I’ve run metal halide, VHO and power-compact lighting over corals for most of that time. The biggest lesson from all of it is simple: anything that lives on photosynthesis lives and dies by light. Let your lighting slip, or let the water get cloudy, and corals start to fade long before you see any obvious problem. Seagrass works the same way. It’s a flowering plant that needs clear, bright water, and when runoff clouds a bay, the meadow starves slowly and quietly.

That’s why, when people ask me why dugongs are endangered, I don’t just talk about nets. Nets kill dugongs quickly and visibly, but murky water and lost seagrass kill them slowly, by starvation and by females that stop breeding. If I had to pick one thing that would do the most good for dugongs over the long term, it would be protecting the water clarity of the bays they feed in. For other species facing similar problems, see our list of the rarest sea animals.