Australian whales prove nosey neighbours

New research shows some eastern Australian humpback whales are taking a trip through New Zealand and Pacific waters on their way to feeding areas in the Antarctic.

Before, it was assumed the whales travelled straight down the east coast of Australia from breeding grounds near the Great Barrier Reef.

But this study shows some whales travel to waters near Noumea and Tonga and others to New Zealand, before heading south.

Wally Franklin from Southern Cross University’s Marine Ecology Research Centre, co-authored the study.

Presenter: Geraldine Coutts
Speaker: Wally Franklin, Southern Cross University’s Marine Ecology Research Centre

Franklin: This paper involves 21 scientists, members of the South Pacific Whale Research consortium and scientists from New Zealand Fisheries as well as colleagues from the Southern Cross University Whale Research Group. These scientists have been photographing Humpback whales in the breeding areas now for well over a decade and have accumulated a great deal of information. Having that foundation of information, when we obtained the photography from New Zealand and Balleny Islands in the Antarctic, we were able to use that base of information to actually make the determination that we did. And what we were able to show is that for the first time we had clear evidence that some of the whales coming through New Zealand waters, particularly southern waters are in fact from eastern Australia and we didn’t previously understand this fully. We also found that some eastern Australian whales are going to Noumea, but the data did make it quite clear that Noumea is a separate populations of whales, but some of our whales are just popping in there to say hello and probably mix and meet with new friends.

Coutts: And were any of the whales tagged?

Franklin: These whales were tagged with a method called photo-identification. Now what that means is that Humpback whales have beautiful markings on their body, black and white pigmentation and particularly their underside tail flukes, the shape and the patterns on their underside tail fluke, plus the trailing edge of the fluke, the serrated edge of the fluke means that these are precise means of identifying individuals. For example, in the Harvey Bay catalogue, developed by my partner, Trish Franklin. There are now some 3,000 individual Humpbacks that Trish is able to identify from photography. So we were able to take the photographs of individuals that were obtained from Cook Strait, between the North and South Islands, and from the Balleny Islands and match these against the eastern Australian catalogues and the Pacific catalogues and that led us to the conclusion.

Coutts: Well a by-product of Japan’s whaling program. They’ve been a number of documentaries made and a number of which has actually showed the migration and the considerable migration of some of the whales and it’s hundreds if not thousands of kilometres. So why is it that we’re only finding out about the Humpback whales migration programs now?

Franklin: Well, that also is a very interesting question. The thing is Geraldine that Humpback whales migrate over vast distances. It’s been quite a challenge to get data from Antarctica and it’s only in the last couple of years that we’re actually getting photo-identification information from Antarctica. The data that we use was obtained by a New Zealand Fisheries expedition down to and around the Balleny Islands, but the Australian government are in fact funding expeditions. They have an expedition down to Antarctica in February, this year and that is collecting further information. The point being that we do have available to us benign techniques to actually gather the information to answer all the questions we need to address and answer regarding Humpback whales and regrettably, the Japanese approach is to kill the whales to get the data.

Coutts: Now, the Australian Humpback whales if we can label them that way are home bodies. They like to stay close to home and venture only as far as Noumea and Tonga?

Franklin: Well, that’s something we hope to get more insight into. We suspect that some eastern Australian whales may go a bit further afield, to Tonga, for example. We have some recent evidence which is not yet published that some whales from Harvey Bay actually go through the Bass Strait and head way across to the west, down below Western Australia into the Indian Ocean. There’s still lots of mysteries about the Humpback whales. They travel over vast distances and you do need a large group of people, such as we’ve had for this study involved to be able to obtain the information and to work out what’s going on and I think that’s one of the exciting things about being a researcher of these amazing creatures is that they still have secrets and surprises for us to uncover.

Coutts: And they are in fact using New Zealand waters as well, the Australian Humpbacks?

Franklin: That was quite exciting to discover that that they’re clearly using New Zealand waters. We suspect the eastern Australian whales are coming through Cook Strait and probably south of the South Island, whereas the whales heading up to Noumea and to Tonga are likely travelling up past the North Island and heading up to their destinations. And the other thing that tells us is that this is an area where the two populations, where the populations from Noumea and Tonga and eastern Australia are in fact mixing, so there’s a heck of a lot more complexity going on amongst these whales than we previously thought.

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