Threats to Dugongs
Overview
Dugongs are particularly susceptible to environmental change because they reproduce slowly, mature late, and depend almost entirely on seagrass meadows in shallow coastal waters. These habitats often overlap with areas of intense human use, exposing dugongs to multiple, sometimes overlapping pressures. Many of these threats create cumulative effects that can significantly reduce both dugong survivorship and fecundity. Consequently, effective dugong conservation requires addressing both the direct causes of mortality and the environmental conditions that support the species' long-term persistence.
Threats to Dugong Survivorship
Interactions with Fisheries
Interactions with fisheries remain the most significant human-induced threat to dugongs across much of their range, with incidental capture in fishing gear representing the leading known cause of mortality in many Dugong MOU Range States. Entanglement occurs primarily in gillnets, although dugongs are also captured in longlines, seines, trawls and other fishing gear. Mortality is widespread but poorly quantified due to limited monitoring, particularly in artisanal fisheries. Additional impacts arise from abandoned fishing gear, illegal fishing and damage to seagrass habitats caused by unsustainable fishing practices. Reducing bycatch, particularly in gillnet fisheries operating within important dugong habitats, remains a global conservation priority. For more information, please visit Interactions with fisheries.
Traditional Harvest
Traditional harvest has historically been a significant cause of dugong mortality throughout much of the species' range and continues to affect some populations today. While customary harvest remains legally recognized in certain regions for subsistence, cultural and ceremonial purposes, illegal hunting persists in parts of Africa, Asia and the Pacific. Socioeconomic pressures, including poverty, food insecurity and demand for dugong products, can contribute to continued direct take. Although legal protection has been strengthened across most Range States, enforcement and monitoring remain uneven. Given the dugong's slow reproductive rate and limited capacity for population recovery, even low levels of unsustainable hunting can significantly affect long-term population viability. For more information, please visit Traditional Harvest.
Vessel Strikes
Collisions with vessels are a recognized source of dugong injury and mortality throughout much of the species' range, although their overall significance remains uncertain due to limited reporting and monitoring. As coastal development, tourism and maritime activities expand, increasing vessel traffic is likely to elevate collision risk, particularly in shallow seagrass habitats where dugongs regularly surface to breathe. Small or fragmented populations may be disproportionately affected by vessel collisions. Management measures, including vessel speed restrictions, designated transit routes and improved monitoring of strandings and vessel activity, can help reduce collision risk in areas where vessel traffic overlaps with important dugong habitats. For more information, please visit Vessel Strikes.
Stranding of Orphaned Dugong Calves
Responding to stranded orphaned dugong calves is one of the most challenging aspects of dugong conservation. Calves remain dependent on their mothers for at least 18 months, making successful rehabilitation difficult and long-term survival in captivity rare. Rescue decisions must balance animal welfare, conservation priorities and available resources while addressing significant public interest. Several Dugong MOU Range States have strengthened stranding response programmes, improving veterinary knowledge and rehabilitation capacity. However, protecting adult dugongs, reducing the causes of calf separation and conserving seagrass habitats remain the most effective strategies for ensuring long-term population persistence. For more information, please visit Stranding of Orphaned Dugong Calves.
Predation
Natural predation contributes to dugong mortality, although its overall influence on populations remains poorly understood. Tiger sharks, killer whales and saltwater crocodiles are known to prey on dugongs, but it is often unclear whether observed interactions involve active predation or scavenging. Dugongs appear to reduce predation risk through behavioural adaptations, including selecting shallow calving areas and altering habitat use in response to predators. While predation contributes to natural mortality, understanding these interactions provides valuable insights into dugong behaviour and habitat requirements that can support effective conservation and management. For more information, please visit Predation.
Threats to Dugong Fecundity
Habitat degradation is the greatest long-term threat to dugong reproduction, with the widespread loss of seagrass meadows reducing food availability and leading to poorer body condition, lower reproductive success, increased foraging movements, and higher mortality. Climate change is expected to intensify these impacts by causing marine heatwaves, sea-level rise, and more frequent extreme weather events that further damage seagrass ecosystems.
Additional human-related pressures, including acoustic disturbance from vessel traffic, tourism activities, pollution, contaminants, plastics, and land-based runoff, may disrupt feeding behaviour, degrade habitat quality, and increase health risks.
Although diseases, parasites, and contaminant exposure have been documented in dugongs, their population-level effects remain poorly understood, with evidence suggesting they are often linked to nutritional stress and environmental degradation. Overall, cumulative human impacts on coastal ecosystems pose significant challenges to dugong health and reproductive success, highlighting the need for further research to better understand the impacts of emerging threats. For more information, please visit Threats to Dugong Fecundity.
Conservation Implications
The greatest threats to dugongs are cumulative rather than isolated. Bycatch remains the most significant direct cause of human-induced mortality, while hunting, vessel strikes, habitat pressures, and natural predation add further stress. Because dugongs are long-lived animals with low reproductive rates, protecting adult survival is critical for maintaining healthy populations. Effective conservation therefore requires reducing accidental capture, protecting coastal habitats, managing vessel traffic, supporting sustainable traditional practices, and monitoring threats across the species' range.