Unlocking secrets of  elusive predator
Research: A female shark waiting to be tagged in King George Sound. Picture: Dept of Fisheries

As far as opportunities went, they didn't come much better.

It was July 2010 and the Fisheries Department had got wind of several sharks hanging around a whale carcass at Two Peoples Bay, a lonely stretch of beach east of Albany.

The news came at the perfect time for Fisheries.

The department had just launched a research project to better understand one of the ocean's most elusive creatures - the great white shark.

It also came against a backdrop of public clamour for more information about the animals in the wake of an increasing number of encounters and attacks off WA.

Over the course of the next five weeks, Fisheries officers would hit paydirt, tagging four white pointers in the bay and deploying monitoring buoys to track their movements.

What's more, the episode would shed new light on the behaviour of great white sharks that were drawn into a bay or a beach by a rotting whale carcass.

Researchers found that even after the dead humpback washed ashore, the sharks kept returning for weeks afterwards, sometimes daily.

For Rory McAuley, Fisheries' principal research scientist, Two Peoples Bay was just a taste of the treasure trove of information the shark research program was about to unlock.

"We didn't know what to expect when we went there - it's not easy trying to find these fish even at the best of times," Dr McAuley said. "To tag four of them at the same place within such a short space of time really was beyond our wildest expectations."

This week, at the two-year mark of the three-year project, Dr McAuley gave _The Weekend West _ a rare insight into its trailblazing findings.

What those findings have revealed is the clearest picture yet of WA's great white shark population.

Dr McAuley said researchers now knew much more about the sharks: what they do, where they go, when they are most abundant and how lonesome they are.

He said contrary to some beliefs, great whites did not swim close to the shore often - only about 15 per cent of the time among monitored sharks.

Notions that some sharks stayed in pairs were also dismissed, after Fisheries tracked two sharks that had been together off suburban Ocean Reef in 2012 and found they inevitably parted ways.

But the project has helped confirm many perceptions held about great whites, such as their extraordinary endurance.

Dr McAuley said in one case, a tagged shark was recorded off the Neptune Islands in South Australia before being detected off Rottnest Island 3½ weeks later.

It was a journey of about 2700km and suggested the shark had covered about 114km a day, or 4.8km/h. Then there was the matter of where the sharks were most likely to be found.

Dr McAuley said there was as yet no apparent reason for that, apart from attractants such as whale carcasses.

Nevertheless, the research had found a receiver off Ocean Reef was the busiest in terms of tagged great white shark detections, having been activated 303 times by four sharks between July 2, 2012 and November 2 last year.

Ellen Cove in Albany was the next busiest, detecting one great white - a 5.5m, 1.5 tonne female - 143 times between March 28 and April 30. At the heart of the project is a sprawling network of shark receivers, first installed off Perth in 2009 and which have since spread to locations off the South West and south coasts as part of the expanded project.

Though a growing number of the buoys are satellite-linked, providing instantaneous information when tagged sharks are detected, most of them are not.

The data from this latter group can only be collected manually.

And it is these VR2 receivers - the "backbone" of the shark monitoring network as Dr McAuley calls them - that are set to unravel so many of the secrets surrounding white sharks.

Dr McAuley said researchers only had the first year's data they gathered.

Though they were in the process of collecting the second year's data, this meant that much of what these buoys had to tell them was yet to be heard.

Aside from the receiver network, Dr McAuley said fitting the sharks with internal transmitters, or "tags", was also going to be crucial to the project's value.

Instead of using an external tag that was liable to fall off the shark within months, if not days, researchers were now guaranteed to be able to track them for as long as the transmitter's battery lasted - at least 10 years.

As he glanced forward to the expected conclusion of the project next year, Dr McAuley said there was still much that was a mystery about WA's great whites.

But he said the research project was helping to change this.

"We're revealing things that have probably always been the case - that sharks swim along our beaches often without us even knowing about them," he said.

"Now with the technology we've been able to apply and the funding we've been given to start looking into these issues, we're finding out our interactions with these animals might have always been a lot more frequent than we care to believe."

The West Australian

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