The dugong (Dugong dugon) is a large, herbivorous marine mammal that inhabits the shallow coastal waters across the Indo-West Pacific, spanning over 40 countries. This gentle giant relies almost exclusively on seagrass meadows for its diet, making its survival inherently tied to the health of these underwater ecosystems. The species is currently assessed as Vulnerable to extinction globally by the International Union for Conservation of Nature (IUCN) Red List, a classification that underscores its high risk of decline in the wild. While the global status is a cause for concern, many regional populations are facing much more severe threats, indicating a fragmented and rapidly diminishing overall distribution. Understanding the unique biology and the various pressures from human activity is necessary to protect this marine grazer.
Biological Vulnerability and Conservation Status
The dugong’s life history traits make it poorly equipped to cope with sudden increases in mortality, contributing to its long-term population vulnerability. Dugongs are exceptionally long-lived, often reaching ages of 70 years or more, but they possess a very slow reproductive rate. Females typically do not reach sexual maturity until they are around 10 to 16 years old.
A female dugong will produce only a single calf after a gestation period of 13 to 14 months, and the interval between births ranges from 2.5 to a maximum of 7 years. This low reproductive output means that a population cannot quickly rebound from elevated levels of adult mortality caused by human activities. Even under ideal conditions, a dugong population is unlikely to increase by more than five percent per year.
While the species is globally listed as Vulnerable, conservation status varies drastically across its vast range, highlighting localized crises. For instance, the dugong sub-populations along the coast of East Africa and those near the Nansei Islands of Japan are classified as Critically Endangered. Populations in other areas, such as New Caledonia, are also listed as Endangered.
Acute Threats: Direct Mortality from Human Interaction
Direct human interactions are responsible for the immediate loss of many dugongs each year. The most widespread and significant cause of mortality is incidental capture, or bycatch, in fishing gear. Dugongs frequently become entangled and drown in commercial and artisanal fishing nets, particularly gillnets and trawls, as they must surface to breathe.
These passive fishing methods are especially problematic because dugongs often feed in the same shallow, near-shore areas utilized by coastal fishing communities. Illegal poaching for their meat and oil continues to decimate isolated populations in regions where they are still hunted. Although legal protection is in place across most of their range, enforcement is often challenging in remote coastal areas.
Fatal collisions with boats and larger vessels represent another substantial source of direct mortality. Dugongs are slow-moving, shallow-water animals that feed close to the surface, making them susceptible to vessel strikes in busy coastal shipping lanes and tourist areas. The creation of “go-slow” zones in areas with high dugong concentrations is a strategy aimed at reducing these traumatic deaths, but the increasing density of marine traffic poses an ongoing risk.
Chronic Threats: Habitat Loss and Environmental Decline
Long-term, systemic threats that degrade the dugong’s environment undermine the species’ ability to feed and reproduce. Dugongs are obligate herbivores that rely almost entirely on seagrass meadows, and the degradation of this food source is the most serious chronic threat. Seagrass beds are being destroyed at an alarming rate due to coastal development projects like land reclamation and dredging, which physically remove or bury the habitat.
Sedimentation runoff from agriculture and poor land-use practices is a major culprit. The resulting murky water blocks sunlight, preventing seagrass from photosynthesizing and ultimately causing it to die. Marine pollution further compounds this problem, with chemical runoff from industrial and agricultural sources and untreated sewage directly harming seagrass health. Plastic pollution also poses a threat, as dugongs can ingest debris while grazing or become entangled.
Climate change adds another layer of complexity, threatening the long-term viability of seagrass habitats. Rising sea levels can inundate shallow seagrass beds with deeper water, reducing the light penetration needed for growth. An increase in the frequency and intensity of extreme weather events, such as tropical cyclones, can physically rip out and destroy vast areas of meadow habitat, which can take years to recover.
Global Conservation Efforts
Addressing the threats to dugongs requires a coordinated international approach that spans multiple countries and diverse local communities. The Convention on the Conservation of Migratory Species of Wild Animals (CMS) Dugong Memorandum of Understanding (MoU) provides a framework for collaboration among range states to ensure the species’ long-term survival. This agreement promotes coordinated actions to protect dugongs and their seagrass habitats across the Indo-Pacific.
A central strategy involves establishing and effectively managing Marine Protected Areas (MPAs) to safeguard critical seagrass meadows and provide safe havens from direct human contact. Many projects focus on enhancing community-based stewardship, recognizing that local populations must be involved in conservation efforts. These initiatives often include developing alternative, sustainable livelihoods for coastal communities to reduce reliance on destructive fishing practices that accidentally harm dugongs.
Regulatory changes are also being pursued, such as phasing out certain types of fishing gear, like gillnets, in identified dugong feeding grounds. International efforts are working toward the “2030 Seagrass Breakthrough,” a global initiative to halt seagrass loss and double the effective protection of these underwater ecosystems. This focuses on integrating dugong habitat mapping into broader coastal planning to ensure protective measures are based on scientific data.