Un­lock­ing the lan­guage of killer whales

Southern Gazette (South Perth) - - Footy Finals 2015 - Pia van Straalen

THE tran­sient killer whale is not typ­i­cally con­sid­ered one of Aus­tralia's na­tive ocean crea­tures, let alone one of Western Aus­tralia's, but 24 nau­ti­cal miles off Bre­mer Bay in the Bre­mer Canyon, a pop­u­la­tion of be­tween 50 and 100 or­cas live mostly undis­turbed.

The ag­gre­ga­tion was dis­cov­ered in 2005 and has since be­come the most pop­u­lar lo­ca­tion in the coun­try for killer whale re­search.

Curtin Univer­sity PhD candi- date Re­becca Wel­lard (pic­tured be­low) be­gan study­ing marine mega fauna 10 years ago and two years ago she de­vel­oped an in­ter­est in killer whales’ bioa­cous­tics and com­mu­ni­ca­tion.

She said since the dis­cov­ery of the pod was so re­cent, there was a lot to learn about na­tive WA killer whales.

“It is a fron­tier science, we're not sure where they're com­ing from or where they're go­ing,” she said.

Ms Wel­lard's pas­sive acous­tics mon­i­tor­ing is a non-in­va­sive hy- drophone over the side of the boat to help un­cover how the whales in­ter­act while so­cial­is­ing, trav­el­ling and hunt­ing.

She said find­ings could de­ter­mine whether WA killer whales com­mu­ni­cated in another 'lan­guage' to their north­ern coun­ter­parts.

“My study is into the acous­tics and com­mu­ni­ca­tion be­tween the killer whales and to see if it's ge­o­graphic,” Ms Wel­lard said.

In the North­ern Hemi­sphere, where the species has been stud­ied at a much greater level, pods have been known to de­velop their own di­alects.

They com­mu­ni­cate us­ing burst-pulse sounds and whis­tles, and they echolo­cate us­ing click­trains.

Killer whales are the largest an­i­mal in the oceanic dol­phin fam­ily.

They are an apex preda­tor, mean­ing their only threat is hu­mans.

An adult orca can mea­sure up to 9.8m and live for about 80 years.

The old­est known killer whale 'Granny' is es­ti­mated to be 103years-old.

Ms Wel­lard said the mam­mals live to­gether all their lives and calves do not leave their mother.

She said at the Bre­mer Canyon, a fe­male orca nick­named Split Tip, be­cause of a tear in her dor­sal fin, vis­ited the boat ev­ery time she vis­ited the re­gion.

“They are ex­tremely in­tel­li­gent, they are in­ter­ac­tive and in­quis­i­tive,” Ms Wel­lard said.

The acous­tic study can be viewed at http://dx.plos.org/ 10.1371/jour­nal.pone.0136535.

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