Australian humpbacks challenge breeding grounds assumption

May 14, 2014
It is likely the whales are mixing at summer feeding grounds near Antarctica and may be attracted across the country by food or mates. Credit: Christopher Michel

Humpback whales from WA are mixing with those on the east coast of Australia and are genetically similar despite their breeding grounds being 2500km apart.

A genetic study of the west coast and east coast populations of humpbacks (Megaptera novaeangliae) found little difference between the two, even though WA humpbacks breed off the Kimberley coast while east coast humpbacks are thought to mate and calve at the Great Barrier Reef.

Centre for Whale Research managing director Curt Jenner says it is likely the whales are mixing at summer feeding grounds near Antarctica and may be attracted across the country by food or mates.

"The are obviously very separate but when they go down to the feeding grounds it becomes a bit muddy," he says.

"Because Antarctica's a continent that you can circumnavigate if you're a whale, just by swimming around in a season, it's quite easy for those populations to mix."

Mr Jenner says on a trip south of Australia in January he saw east coast and west coast humpbacks separated by only about 500 miles (800km).

"If you're a whale swimming that distance it would only take you a week to cross between population boundaries," he says.

The finding, published in Marine Mammal Science, is supported by research into whale songs in the 1990s that suggested WA humpbacks could swim to the east coast.

The scientists compared samples collected from 131 individual whales off the coast of Tasmania and New South Wales and a further 205 whales off Exmouth.

Mr Jenner, who supplied material for genetic testing from the WA humpbacks, says samples are taken using an air rifle like that used by vets to shoot tranquilliser darts.

"Instead of a dart which would inject an anaesthetic into the animal, we actually just have a hollow tip on the end of the dart," he says.

"It just takes a little plug of skin, probably about 2mm in diameter and about 20mm long."

The researchers slowly pace alongside the whale until the animal is comfortable with the sound of the vessel, wait until the whale comes to the surface and then line up for a shot.

Mr Jenner says it is possible are also using Antarctic waters to migrate between Australia and other continents.

"[That's] the next premise, that these whales not only are travelling between eastern and western Australia but they're probably also moving into the South Pacific and maybe across to South America and then from South America perhaps across to Africa," he says.

"Those linkages have yet to be made but it's not impossible that that's what's going on."

Explore further: Godwits are flexible... when they get the chance

More information: Schmitt, N. T., Double, M. C., Jarman, S. N., Gales, N., Marthick, J. R., Polanowski, A. M., Scott Baker, C., Steel, D., Jenner, K. C. S., Jenner, M.-N. M., Gales, R., Paton, D. and Peakall, R. (2014), "Low levels of genetic differentiation characterize Australian humpback whale (Megaptera novaeangliae) populations." Marine Mammal Science, 30: 221–241. doi: 10.1111/mms.12045

Related Stories

Humpback whales rebounding on Brazil's coast

Sep 02, 2012

(AP)—An institute that tracks the population of Humpback whales that reproduce along Brazil's coast says the number of the once-threatened mammals has tripled over the last 10 years.

Rare white whale calf spotted off Australia

Sep 29, 2011

An extremely rare white humpback whale calf has been spotted near Australia's Great Barrier Reef in an event witnesses described Thursday as a "once in a lifetime experience".

Humpback whale beats long-distance record

Oct 13, 2010

A humpback whale has broken the world record for travel by any mammal, swimming at least 9,800 kilometres (6,125 miles) from the Atlantic to the Indian Ocean in search of a mate, marine biologists reported ...

Australia expecting massive whale watching season

Jun 01, 2011

Australia marked the start of its whale-watching season Wednesday with predictions that some 4,000 of the giant animals will be spotted as they make their way along the coast during winter.

Recommended for you

Godwits are flexible... when they get the chance

2 hours ago

Black-tailed godwits are able to cope with unpredictable weather. This was revealed by a thorough analysis of the extraordinary spring of 2013 by ecologist Nathan Senner of the University of Groningen and ...

Do you have the time? Flies sure do

14 hours ago

Flies might be smarter than you think. According to research reported in the Cell Press journal Current Biology on May 28, fruit flies know what time of day it is. What's more, the insects can learn to con ...

Barking characterizes dogs as voice characterizes people

17 hours ago

An international group of researchers has conducted a study on canine behavior showing that gender, age, context and individual recognition can be identified with a high percentage of success through statistical ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

BSD
5 / 5 (1) May 14, 2014
I'm surprised we have any left at all after the Japanese arrogantly pillage the Southern Ocean every year.
Sinister1812
not rated yet May 14, 2014
Probably, if it wasn't for Sea Shepherd, there wouldn't be.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.