Maintaining mystique: little known lives of killer whales

SS-SplitFinEden9-10-14 - WEB under licence COPYRIGHT strictly use with story only

Few people know it, but killer whales live in Gold Coast waters.

They are one of the most poorly understood marine mammals in Australia, particularly in Queensland, which is why the Australian Orca Database (AOD) is trying to develop a higher profile for them.

Since 2000, cetacean researcher David Donnelly has struggled to engage more community groups, fishermen and charter operators in the Sunshine State to contribute to the AOD citizen science program, but orcas have such a small media profile they are largely ignored.

“We don’t know much about Australia’s top level predator,” Donnelly says, and when he says “top level” he means that killer whales feed on white sharks.

The problem with not having enough information about the whales, which are not actually whales but the largest of the dolphin species, is that they can’t get an accurate conservation status – they are rated as data deficient.

“Our belief is it’s likely that killer whales are not in large numbers in Australian waters and it’s only through analysis of existing data we can find out what the population status might be.”

“Only then can we give them an accurate conservation rating,” the marine researcher says.

He says a community science initiative is the way to go to collect photos and sighting information.

“They are very difficult to research in the field because they are hard to find as there are no known places where they congregate.”

The data that AOD has collected on killer whales since it started in 1994 in Antarctic’s Macquarie Island is just the tip of the iceberg.

Surveys by the Australian Antarctic Division see lots of killer whales in the Southern Ocean, but that data belongs to the Australian government, so “any sightings in Queensland are worth their weight in gold” for Donnelly.

The last sighting in Queensland was only a few days ago, around 13 June at South Stradbroke Island.

Queensland has a small AOD network including the University of Queensland Cetacean Ecology and Acoustic Laboratory, the Parks and Wildlife Service that came to the aid of the mass stranding of orcas at Hervey Bay last year, and teams at Stradbroke Island and Peregian Beach.

Killer whales are extremely intelligent and their behaviour reflects this.

They hunt cooperatively making them more successful than white sharks, but alpha males often don’t participate in the hunts though they share in the kill.

They take fish from fishermen, particularly long lines and leave the hooks. Called depredation, it’s a common problem in Tasmania, New Zealand and New South Wales.

They’re very good at sharing information, so the sound of a long line pulley system is like a dinner bell for killer whales, Donnelly says.

The pods are matriarchal led by a female and they have a very high pod fidelity.

“We know one female who has been with the same male since 1996,” he says.

Her name is Split Fin because her fin was split by a boat strike. She has been seen in groups of six to 15, but as pods can communicate long distances the groups can be very spread out, unlike dolphins.

One sighting recorded the distinctive orca matriarch 970km away from the previous sighting 16 days earlier, clear evidence that orcas migrate great distances.

“There has never been an orca attack on a human being in the wild. They are very rarely curious and a little standoffish,” Donnelly says.

Capable of speeds of 20kph, Donnelly says they throw up an impressive amount of white water.

Incredible animals and yet not until two years ago was there any dedicated research.

Donnelly says analysis of the data is very time consuming so funding is needed, but worth it to know more about these little known cetaceans.

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Call in a sighting 0401 01 1022 or visit ozorcas.com for more info.

 

Caption: This photo of female killer whale Split Fin was taken in Eden, NSW. She is easily identified because of the split in her fin from a boat strike. Killer whales have strong pod fidelity and Split Fin has been sighted with the same male since 1996. Image by Scott Sheehan, under permit ©scottsheehan.com.au

 

 

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