The annual northern migration of humpback whales along the east coast of Australia is under way, with the first sightings reported off the North Coast over the last few weeks.
Wally Franklin, a researcher with Southern Cross University’s Whale Research Centre and co-director of The Oceania Project, said the northern migration usually began around the start of May.
“About this time we begin to see one or two whales and now we are into May the flow will start to pick up. The peak of the northward migration past Byron Bay occurs in June and July. There is evidence that the timing of the migration can vary between years, but generally the whales are incredibly regular,” Mr Franklin said.
Humpback whales leave the feeding grounds in Antarctica to head north to the warmer waters of the Great Barrier Reef to breed and give birth. They spend some months off the north-east coast of Australia before heading south again.
“The flow is a steady procession that runs northward through May, June and July and in late July some whales begin moving south again,” he said.
“All the mating actually takes place off the Queensland coast. That’s where calves are conceived and usually born. In the most fundamental way that is their home. The motivation for going south to Antarctica is food.
“The other really interesting feature is that the structure of the migration is very orderly.”
While the east coast humpback whale population is now estimated to be around 11,000, Mr Franklin said it was still far from being fully recovered. Prior to the last period of commercial whaling the population was estimated to have been at least 40,000.
“Even though we are observing and measuring a steady rate of increase, it’s really important to remember the population is a very long way from being fully recovered. There are many things that are going to impact on those numbers continuing to increase, including pollution in the food chain and the risk of entanglement,” he said.
Mr Franklin said climate change could also have an impact on the habitat in the Great Barrier Reef and the food supply in the Antarctica.
The ongoing move by Japan for ‘scientific’ whaling also continues to pose a serious risk to the recovering population, and now Korea has also indicated it might follow Japan’s lead.
Mr Franklin, and his partner Trish, also a PhD student at the Southern Cross University Whale Research Centre, have contributed papers to the International Whaling Commission (IWC) Scientific Committee and will be following closely the next round of meetings which begin June.
Using benign photo-identification techniques they have documented and reported on the movement of humpback whales between Antarctica and eastern Australia and within the Pacific basin.
This year the Franklins will celebrate their 20th year of The Oceania Project, which involves extensive field research in Hervey Bay, which they conduct annually from August to October. The researchers spend a week at a time on a research boat in Hervey Bay photographing, recording and filming the humpbacks.
“The important thing is the long-term nature of the research we are doing and the collection of information on life histories of individual humpback whales,” Mr Franklin said.
Trish Franklin has developed a fluke catalogue of 3000 individual whales, which can now be matched with populations in Antarctica and the Pacific.
“The availability of a major data set is going to be really important and means we can collaborate with other Australian and international scientists and answer questions about the movements of humpback whales, where they are going to feed and whether different groups of whales are mixing,” Mr Franklin said.
“While the eastern Australian group is showing reasonable signs of population increase, the Pacific population is very much smaller and is not showing anywhere near the same levels of increase.”
Mr Franklin said people joining their expeditions as paying interns assisted not only with gathering the data, but in funding this long-term ongoing project.
“We are finding that more and more people are wanting that kind of real hands-on involvement in research,” he said.
PICTURE: A mother and calf, Timantha and Elmo, breach off Fraser Island. Photo by Trish Franklin.