Testing the waters

Bush Heritage is taking its renowned science-backed approach underwater to unlock the secrets of Hamelin Pool.

Much has been made of Hamelin Pool’s incredible Stromatolites, living fossils similar to some of the earliest forms of life on earth, but what of its underwater inhabitants?

Although much research has been conducted through the greater Shark Bay World Heritage Area, Hamelin Pool’s marine life has never been systematically documented.

This gap in knowledge means little is currently known about the ecological processes happening within the pool itself, something Bush Heritage Science Fellow Erica Suosaari says has impeded management planning.

“Although many studies have focused on the Stromatolites, the faunal assemblage in the pool itself has gone largely ignored,” she says. “The lack of baseline data in Hamelin Pool leaves us unable to assess the current health of the system, and the impact of heat waves along with the changing climate.”

A new Bush Heritage project in collaboration with the WA Department of Parks and Wildlife and Curtin University plans to change that.

Introducing BRUVS.

In years gone by, the only way to capture underwater footage was to send down a diver with a purpose-built camera. It was somewhat effective, but researchers couldn’t escape the limitations of diver-operated systems such as fish behaviour changes and observation bias.

A new technology has now changed the game. Baited Remote Underwater Video Systems (BRUVS) have become the predominant method for conducting underwater surveys, providing greater accuracy while also reducing human interference.

Using little more than a steel frame, two cameras and a bait bag containing crushed pilchards or sardines, Bush Heritage researchers are capturing never-before-seen footage of Hamelin Pool’s incredible sea life.

“It was previously thought that Hamelin Pool would have a low diversity of marine organisms, in particular fishes, due to the water’s high salinity,” Erica explains.

“Yet nearly 100 BRUVS drops have already revealed pockets of Hamelin Pool teeming with fish and snake life. One drop alone recorded Snapper, Gobbleguts, Yellowtail Grunters and Bream.”

In addition to providing a platform to collect data for analysis, BRUVS also record invaluable information about the immediate habitat.

“A baseline ecological study for a biologically significant area such as Hamelin Pool is extremely important, as it helps us understand the ecological processes that inform management decisions.”

The project will continue into 2020 and Bush Heritage expects to develop a comprehensive baseline understanding of Hamelin Pool’s faunal assemblage. The data will inform a land management plan that will benefit the pool and protect its species for the long term.