Listening to the Ocean: Recent Adventures from the IMOS Animal Tracking Facility

At SIMS, our scientists often say that receivers are like underwater ears—quietly listening to the movements of marine life day and night. Over winter, the IMOS Animal Tracking Facility team has been out on the water making sure those ears keep working, completing a series of servicing trips that are already revealing some fascinating stories.

In June, the team travelled north to Queensland’s Heron and One Tree Islands. Divers recovered and redeployed seven receivers at Heron and five at One Tree, replacing a few star pickets along the way. These instruments had been in the water for a full year, quietly recording thousands of signals from tagged animals. The payoff was rich: detections of seven different species, including more than a hundred tagged individuals across eight research projects. Each ping adds another piece to the puzzle of how fish, sharks, and rays use these reefs.

Just a few weeks later, attention shifted south to the Stradbroke Island Line. First deployed in 2021, this string of receivers sits in deeper waters between 29 and 50 metres, so each unit is fitted with an acoustic release for retrieval. Rough weather on the east coast made access tricky, but the team managed to bring up four of the five receivers and redeploy them after downloading their data. Despite the delays, the effort was well worth it: more than 6,000 detections were logged, representing twelve species and 219 tagged animals from ten active projects.

Together, these trips are a reminder of why long-term monitoring matters. Every receiver is part of a vast national network, feeding into a shared database that helps scientists track migrations, uncover habitat connections, and understand how marine life is responding to a changing climate. By maintaining this infrastructure, SIMS and IMOS are giving researchers across Australia—and around the world—the tools to listen to the ocean more closely than ever before.