Dugongs, often called “sea cows,” are gentle, herbivorous marine mammals inhabiting shallow coastal waters across the Indo-Pacific. They rely almost entirely on seagrass for their diet. Despite widespread distribution, dugong populations are vulnerable to extinction, with numbers declining significantly. This vulnerability stems from human-induced pressures and environmental changes.
Direct Human-Caused Threats
Human activities cause dugong mortality. Bycatch, the accidental capture in fishing gear, is a primary threat; dugongs frequently become entangled and drown in nets. This is pronounced in artisanal fisheries, where monitoring and enforcement are challenging. Boat and ship collisions also cause severe injuries or fatalities.
Illegal hunting for meat, oil, or tusks endangers dugong populations, despite protective laws. Pollution (plastic, chemical runoff, oil spills) compromises dugong health and habitat.
Loss of Critical Seagrass Habitats
Degradation of seagrass beds threatens dugongs, their primary food source and habitat. Dugongs consume up to 40 kilograms of seagrass daily, their survival dependent on healthy ecosystems. Coastal development (urbanization, port expansion, tourism) often involves dredging and landfilling, destroying these meadows.
Land-based activities contribute to seagrass loss through sedimentation and nutrient runoff. This clouds water, reducing sunlight, and can smother plants. Destructive fishing practices, like bottom trawling, damage seagrass beds by tearing up plants and disrupting the seabed. Since the 19th century, approximately 29% of known seagrass areas have disappeared globally, with accelerating rates of decline.
The Impact of Climate Change
Climate change intensifies threats to dugongs’ seagrass habitats. Rising ocean temperatures stress seagrass ecosystems, leading to die-offs and reduced productivity. This causes extensive seagrass loss, impacting food supply.
Ocean acidification, from increased CO2 absorption, can affect seagrass health. While seagrass meadows can locally buffer acidification, their overall health can be compromised by a more acidic environment. More frequent extreme weather events (cyclones, floods) destroy seagrass beds and alter water quality. Sea level rise can also alter coastal habitats, potentially leading to a “coastal squeeze” where seagrass meadows cannot migrate inland due to coastal development.
Global Conservation Efforts
Conservation efforts safeguard dugong populations worldwide. Legal protections exist through CITES and CMS, regulating trade and promoting conservation. Many countries also have national laws protecting dugongs and their habitats.
Marine protected areas (MPAs) provide safe havens for dugongs and seagrass, regulating human activities. Community involvement and education raise awareness and engage local populations in conservation. Scientific research and monitoring (aerial surveys, satellite tagging) provide data on dugong populations and habitat health, informing management. Rescue and rehabilitation programs assist injured or stranded dugongs.