Animal Tracking in Western Australia

Animal Tracking in Western Australia 

In the turquoise waters off the coast of Western Australia, animals of all shapes and sizes swim through heritage listed seagrass meadows. Through the Gathaagudu Animal Tracking project, or GAT, scientists seek to understand where they are going and how they are faring as the climate is changing. 

The study site and its scholars 

Shark Bay off the Western Australian coast sits at the most western point of the continent. It is one of Australia’s six ‘unique ocean places’ listed on the UNESCO World Heritage List. The noted natural features of the site include vast seagrass meadows and the dugongs that call them home. Also inhabiting the area are sharks, turtles and a range of other marine flora and fauna. 

The GAT project is led by Associate Professor Ana Sequeira, an accomplished marine ecologist and pioneer in the study of global marine animal movements. Joining her are specialist ecologists and traditional owners as well as a team of academic and government collaborators.  

Aside from GAT, Associate Professor Sequeira is the founder of an international ocean conservation project, MegaMove. This project uses data from specialised monitoring tools known as biologgers (more on them soon) to create an advanced, evidence-based map of priority areas for ocean conservation. 

At the heart of both GAT and MegaMove is marine megafauna migration – the movement of whales, sharks, turtles and other species over Earth's vast ocean expanse. While some will make journeys of thousands of kilometres, others may move only locally. Data at all scales can provide clues as to their resilience and their prospects. 

Tracking marine animals involves the attachment of tracking devices to the animals, including the aforementioned biologgers and satellite or acoustic tags. Each of these provides data of a different kind. 

Among these biologgers are ‘CATS Cams’ that capture high-resolution footage of the underwater environment as experienced by the animal (CATS stands for customised animal tracking solutions). These cameras are fitted with accelerometers that record even tiny 3D movements of the animals in the water. Together, the video and movement data reveal how animals move underwater and how they interact with their surroundings. 

Acoustic tags attached to animals send data through to battery-operated ‘listening stations’ deployed underwater. Each acoustic tag emits a unique ‘ping’, allowing researchers to identify which tagged animal the ping came from. The receivers can pick up signals from tags linked to other projects too, helping researchers to collaborate. These monitoring tools are best suited to recording smaller-scale movements. 

In contrast to acoustic tags, satellite tags facilitate the tracking of movements on a larger scale, like annual migrations. Tracking devices transmit location and sometimes temperature data to satellites when the tag breaks the surface of the water.  

To collect data of all kinds, the GAT research team have made 12 trips to Shark Bay and tagged 64 marine creatures. Who are their study subjects, and what's it like to be tagged? 

The study subjects 

Dugongs 

The dugongs inhabiting Shark Bay make up one of the world’s largest remaining populations of these vulnerable creatures. To keep an eye on how they’re faring, their movements are being tracked via satellite tags. On a tagging expedition, researchers head out in a boat, with a small plane overhead to assist with spotting the animals. Once a dugong has been spotted, researchers will join them in the water and gently restrain them against the boat. The dugong will be measured and then fitted with a satellite tracker near its tail – at the caudal peduncle, the narrow point where the tail meets the body. Back on land, a receiving station will ‘listen’ out for signals from the satellite tags and gather location data over time. 

Sea turtles 

Shark Bay is home to both green turtles and loggerhead turtles. After catching them in chest-deep water, when possible, researchers bring the turtles onto the boat, where they will attach a tracker to the shell (and maybe even conduct an ultrasound to check for developing eggs). They then release the turtle back into the wild. As the tagged turtle heads off on its way, the researchers return to land, perhaps spotting dolphins, sea snakes and tiger sharks on the way.  

Data collected from satellite tags have shown that turtles expand their foraging range when the quality of seagrass beds declines. Although turtles can adjust to changing conditions by expanding the size of their feeding areas, doing so requires them to expend more energy, which can in turn reduce the energy available for growth, reproduction and overall health. This highlights the importance of preserving the quality of their habitat. 

Sharks 

Tagging a shark, as you might expect, requires a slightly different technique. Researchers will deploy a fishing line with bait and then wait. When a shark arrives, researchers will work from inside the boat to attach a satellite tag to its dorsal fin. Sometimes an acoustic tag is also implanted on the shark’s body. This is usually the case when acoustic receivers have also been deployed nearby. These receivers are carefully weighted to keep them upright and in place at the bottom of the ocean. Once the shark has been tagged, it is free to go. 

To date, collected data have revealed that tiger shark movements are impacted by salinity, water depth and the density of seagrass beds. Dense seagrass beds with lower salinity were identified as the most suitable habitats. Since sharks are top-order predators, their distribution likely also influences the distribution of prey. 

To put moving pictures to the research stories shared here, visit the GAT project website. 

References 

‌D’Antonio, B., Meekan, M., Ferreira, L. C., Taylor, M. D., Pattiaratchi, C. B., & Sequeira, A. M. M. (2025). Salinity drives the distribution of a top-order predator, the tiger shark (Galeocerdo cuvier), in an inverse estuary. Scientific Reports, 15(1). https://doi.org/10.1038/s41598-025-92272-6 

GAT - Gathaagudu Animal Tracking Project. (2025, June 7). https://gatproject.net/ 

‌Shaw, Dylan. (2021). aerial view of body of water during daytime [Photograph]. Unsplash. https://unsplash.com/photos/aerial-view-of-body-of-water-during-daytime-OR_D1sdsOVA 

UNSESCO. (n.d.). Shark Bay, Western Australia. UNESCO World Heritage Centre. https://whc.unesco.org/en/list/578/ 

UNSESCO. (n.d.). World Heritage Marine Programme. UNESCO World Heritage Centre. https://whc.unesco.org/en/marine-programme/