The city's gentle grazers
Moreton Bay, a large, sheltered body of water next to the metropolis of Brisbane, supports the world's only major dugong population near a capital city. This group of 600 to 800 individuals is the southernmost resident population of Dugong dugon on Australia's east coast. These large mammals, which can grow up to 3 meters long and weigh over 600 kilograms, are more closely related to elephants than to other marine mammals like dolphins. They spend their days grazing on the bay's extensive seagrass meadows, earning them the nickname "sea cows." An adult consumes about 30 kilograms of seagrass daily, often leaving visible feeding trails along the seafloor.
The population's survival depends entirely on the health of these underwater pastures. Moreton Bay contains seven species of seagrass, with the largest meadows located on the Eastern Banks, between Moreton and North Stradbroke islands. Here, the water is clearer, allowing sunlight to penetrate to depths of 12 meters and support the dugongs' preferred food. Their favorite seagrass species is Halophila ovalis, which is high in nitrogen and low in fiber, making it easily digestible. Research shows that the dugongs' grazing patterns actually promote the growth of this specific seagrass, a process sometimes called "cultivation grazing."