Spotted from above: Innovative aerial surveys help monitor the Reef’s dugongs

Dugongs are coastal marine mammals of high conservation and cultural value, particularly for Aboriginal and Torres Strait Islander peoples. However, these gentle underwater giants are subject to a range of human threats including entanglement, collisions with boats and the decline of important habitats such as seagrass meadows. This has led them to be listed as Vulnerable on the International Union of the Conservation of Nature’s (IUCN) Red List of Threatened Species.

The Great Barrier Reef supports one of the world’s largest dugong populations, which is one of the key reasons for the Reef’s listing as a World Heritage Area.

Surveying and counting these elusive marine mammals across the vast breadth of the Reef is no easy task. With funding from the partnership between the Australian Government’s Reef Trust and the Great Barrier Reef Foundation, one team is tackling this project head on.

Since the 1980s, aerial surveys have provided valuable information on dugong distribution and abundance in many parts of Australia, including the Reef. These surveys have occurred at the same time of year, every five years. The data collected is vital for researchers and conservationists, who use it to enhance the management and protection of the species.

Observer aerial surveys of dugongs along the southern Great Barrier Reef, which runs from Bundaberg to Cooktown, were last conducted in 2016, and the northern part of the Reef, from Cooktown to Cape York, in 2018-2019. 

In 2020, the Reef 2050 Integrated Monitoring and Reporting Program (RIMREP) identified that increased dugong survey efforts were required, particularly in the southern Reef. Importantly, the whole east coast of Queensland—which spans the entire Great Barrier Reef and vital dugong habitats south of the Reef including Hervey Bay and Moreton Bay—has never been surveyed in one cohesive monitoring project, until now.

James Cook University is leading an innovative project with the support of a consortium of partners to transition to new technologies to monitor dugongs on the Reef. They are harnessing a combination of methods including custom-designed camera systems fitted onboard manned survey aircrafts, drones and machine learning-based image analysis. During these surveys, researchers also capture opportunistic data on turtles and other large marine animals, so they can share that information with other teams across RIMREP.

The project is led by Dr Christophe Cleguer and his dedicated team. This year, the team has spent over 25 days out surveying the central and southern regions. During the two to three-hour aerial surveys, the plane is flown in parallel lines along the coastline, with observers looking out for dugongs and other animals, while the cameras attached to the bottom of the plane record photos.

Surveys are conducted at low altitudes and conditions inside the plane can be quite challenging.

“On good weather days, we would fly for several hours before dedicating additional hours to data transcription. In such conditions, it is crucial to assemble a team of enthusiastic and resilient individuals with a positive spirit,” Dr Cleguer said.

Drones are now also being trialed, as they provide several benefits compared with manned flight surveys.

“They eliminate the risk of human injury or fatalities during surveys, reduce the carbon footprint of aerial surveys, improve accuracy in flight paths and, hopefully in the future, will lower the operational costs of conducting large-scale surveys,” he said.

Given the current challenges involved in the continuous monitoring of this species across the Reef and its coastlines, the innovation of survey techniques will help provide better estimates of dugong abundance, as well as habitat mapping.

An important part of this survey is engagement with Traditional Owner groups across the Queensland coast. Through this partnership, the team is sharing and discussing survey objectives, methods and results, which will help Traditional Owners inform ongoing sea country management.