Dugong Populations in Decline in Great Barrier Reef
Habitat Loss and Gillnet Fishing Threaten Marine Mammals
Dugongs, manatee-like marine mammals, are facing a decline in numbers in the Great Barrier Reef, according to a recent study based on aerial surveys conducted in 2022. The study identified habitat loss and gillnet fishing as major threats to these vulnerable animals.
Habitat Loss
Seagrass habitats, which are essential for dugongs as a food source, are being degraded by climate change and pollution. When seagrass beds are disturbed or destroyed, dugongs may attempt to relocate to other areas, but their survival is uncertain due to food scarcity.
Gillnet Fishing
Gillnets, which can stretch over a kilometer in length, indiscriminately catch marine life, including dugongs, dolphins, and turtles. These nets pose a significant threat to dugong populations, as entanglement can lead to injury or death.
Population Decline
The study found that dugong numbers have declined significantly in certain areas of the Great Barrier Reef. In Hervey Bay, the population has dropped by approximately 5.7% annually since 2005. The decline is likely attributed to two major floods in 2022 that devastated seagrass habitats in the region.
Conservation Efforts
To address the threats facing dugongs, the Australian and Queensland governments have announced a $160 million package to phase out gillnet fishing in the next few years. This measure is expected to significantly reduce the risk of dugong entanglement and injury.
Importance of Seagrass
Seagrass plays a critical role in the survival of dugongs. These underwater plants provide the majority of their diet, and their health is directly linked to water quality. As climate change and pollution continue to impact water quality, seagrass beds face further degradation, posing an ongoing threat to dugong populations.
Dugong Vulnerability
Dugongs are particularly vulnerable to environmental changes due to their reliance on seagrass. When seagrass habitats are lost or compromised, dugongs face challenges in finding alternative food sources and may experience malnutrition or starvation.
Monitoring and Research
Regular aerial surveys are conducted by researchers at James Cook University to monitor dugong populations in Queensland. These surveys provide valuable data on population trends and help identify areas where conservation efforts are most needed.
The Importance of Conservation
The decline of dugong populations in the Great Barrier Reef highlights the need for urgent conservation measures. Protecting seagrass habitats, phasing out gillnet fishing, and addressing climate change impacts are essential steps towards ensuring the long-term survival of these iconic marine mammals.