Dugongs are vulnerable marine mammals that depend exclusively on seagrass for nutrition, and the global decline of seagrass beds is causing nutritional stress, habitat loss, and population decline.
Dugongs in degraded seagrass habitats experience chronic nutritional stress as they must travel further and dive more frequently to obtain adequate food. Malnourished dugongs have reduced immune function and reproductive capacity, creating a welfare and demographic spiral. Boat strikes are particularly welfare-significant: prop injuries cause severe lacerations and internal haemorrhage; animals that survive strikes may carry permanent disfiguring wounds that impair swimming. Entanglement in fishing gear causes drowning. Calves separated from their mothers have very poor survival prospects. In areas of severe seagrass loss, dugongs have been documented travelling hundreds of kilometres to alternative feeding grounds, imposing enormous energetic costs on animals that normally have small home ranges. The welfare of individual dugongs is directly tied to seagrass ecosystem health, making coastal water quality and eutrophication control animal welfare issues.