Geographe Bay a family-friendly destination for more than just humans

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Geographe Bay a family-friendly destination for more than just humans

By Peter de Kruijff

Comparing the crusty-looking white growths on the heads of southern right whales from a bank of photos taken over 30 years off the coast of Western Australia could help lead to greater protection for the endangered species.

Researchers believe more mother whales are coming to Geographe Bay, a 994 square kilometre water body extending from Cape Naturaliste to just south of Bunbury in the state’s South West, as the population which migrates to Australia annually recovers from historic whaling practices.

Southern Right Whales in Western Australia.

Southern Right Whales in Western Australia.Credit:Blair Ranford

The global population of the southern right whale – which can measure as large as 17.5 metres at a weight of about 80 tonnes – is thought to be more than 13,000, but there was once estimated to be as many as 70,000 in the late 1700s.

The species received protection in 1935, when there may have been fewer than 300 individuals remaining, but illegal whaling for another 30 years impacted numbers.

Southern right whales spend a great deal of the year feeding in the ocean around Antarctica and populations have recovered to the point where about 3400 then migrate to the southern coast of Australia, most of them to South Australia and the west, for breeding and calving for about three to four months.

Mother whales have a new calf once every three years on average.

Researchers from Edith Cowan University and Western Whale Research now think there is an increase in females returning to what might have been historical calving grounds pre-whaling in places like Geographe Bay and Flinders Bay in the South West.

ECU associate Professor and lead researcher on the project Chandra Salgado Kent said Flinders Bay was being well utilised by mothers and calves and they believed were starting to appear more in Geographe.

“These animals as they recover, at an estimated 6 per cent per year, they are certainly presumably going to need to re-establish historic breeding grounds,” she said.


“We were able to gather evidence at least one mother returned after nine years [to Geographe].

“What that shows is there is long-term site fidelity – which means calves ... come back to that area.”

Preliminary results from the project – which draws on photos taken by volunteers, whale watching charters and Chris Burton from Western Whale Research – shows at least 229 different whales have visited the two bays in the past three decades.

This was discovered by comparing callosities – rough calcified skin patches like a callus which are grey or white in appearance with small crustaceans and barnacles also forming – on the heads of the whales which can help identify individuals much like a human fingerprint.

The research was made possible with funding by the Australian government under the National Environmental Science Program but associate professor Salgado Kent said if complementary surveys were undertaken it could help capture a broader area of locations the whales were breeding.


“We could then ensure we’re covering the seasons consistently every year or filling in gaps where the citizen science surveys hasn’t focused on,” she said.

The whales gather in other places like Israelite Bay, Bremer Bay, Doubtful Island and several locations across the border in South Australia.

Knowing more about the species and their needs in calving grounds will help inform protection strategies for the marine mammal, like the current review of its national conservation management plan.

Such management plans are taken into account when major projects which could impact on the whales are in the development phase.

Currently there are two offshore wind projects proposed south of Perth including a 200-turbine development between Mandurah and Bunbury.

The Leeuwin Offshore Wind Farm would have a 4200 square kilometre project envelope and is currently going through the federal environmental approval process.

A referral document from the developer, Copenhagen Energy, recognises further investigations were required into the timings of whale aggregations, for a few different species, in the area to assess potential impacts.

The company recognised there could be potential impacts for whale species with activities like pile driving, but it believed that could be managed.

Kent said while more research could inform different strategies, recreational water users should also be careful in areas the whales congregated.


“We may not see them until we’re right on top of them, so make sure we’re travelling at low speeds in these regions ... so we’re not disturbing them while they are undertaking that vital life process which is feeding the young and ensuring their calves are growing,” she said.

“Sometimes you see the calf on the back of the mum as well in a protective space ... they’re just absolutely fantastic to watch.”

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