Whale watchers have witnessed a dramatic chase off a Sunshine Coast beach as a mother humpback and her calf used a tour boat for protection from pursuing males.
Passengers aboard Noosa Thriller Ocean Adventures witnessed the 45-minute spectacle near Sunshine Beach in late June.
Owner and skipper Brent Milne said they first noticed “splashing and lots of fast movements”.
He said he followed national approach guidelines and shut down his boat’s engines as the whales approached.
“At one stage, the mother and calf swam straight to and under the boat, when she was attempting to shield the calf from the three males,” Mr Milne said.
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While he said the behaviour was typical of humpbacks, it was unusual to see it at that time of year.
“This encounter was unique for this early in the whale migration season,” he said.
“We are finding, in the last few years, there are more newborn calves earlier in the season due to the expanding population of whales migrating our east coast.”
Mr Milne, who has operated whale tours off the east coast for three decades, said passengers were fortunate to witness the event.
“This was spectacular viewing and a natural part of nature and whale behaviour,” he said.
“It enabled us to provide further education and awareness to the public and passengers lucky enough to be onboard for that tour.”
University of the Sunshine Coast animal behaviouralist and marine mammal expert Dr Alexis Levengood said the footage appeared to show what is known as a ‘heat run’.
“It is likely a few male humpback whales are interested and trying to mate with the mother,” she said.
“She has clearly only recently given birth. The calf is likely less than two weeks old, based on its dorsal fin still being floppy. This stiffens up gradually over time.
“The mother appears to bring the calf close to the Noosa Thriller vessel to use it as protection and to guard her calf, and potentially herself a bit.
“Mothers will go to extreme lengths to protect their calves.
“Typically, females are focused on the survival of their calf while males are focused on gaining access to the next female.
“Competitive males trying to mate can be quite aggressive in their pursuit of females. It appears as if a few males are aggressively jockeying for position, with lots of splashing visible, to get near the mother.
“The mother seems to defensively position her body between the males and her calf, trying to block the males and escort her calf toward the ecotour vessel to use it as protection for her very young calf.”
Dr Levengood said such interactions weren’t commonly seen on tours.
“You don’t always get to see males competing for females when out on the water or whale watching,” she said.
“We more typically see aerial behaviours like breaches, pec fin slaps, tail slaps and travelling behaviour.”
She said the whales were on their annual travels.
“They travel from Antarctica up to the warmer waters of the Great Barrier Reef for calving and breeding and then return back on their southern migration to Antarctica. We typically see humpbacks in South-East Queensland during May to November,” she said.
She said it was a somewhat unusual encounter for a couple of reasons.
“It’s incredibly exciting to see a newborn calf as viewed in this video, as calves are usually born in the Great Barrier Reef as opposed to on the migration,” she said.
“But we are seeing more and more calves born during the migration each year.
“What is somewhat unusual here is that mothers with newborn calves don’t typically mate – they normally give birth to calves every two to three years as opposed to yearly and gestate for about 11 months – so this female isn’t or shouldn’t be receptive to mating.
“Males will typically engage with receptive females instead and can be involved in heat runs where many males chase and vie for position to get access to and mate with a receptive female in oestrus.
“Mothers and calves nearby tend to remain quite quiet and lay low to avoid gaining male attention.
“However, keen males can, and will, still try to gain access to and mate with females with a calf. In these instances, males will try to separate the calf from the mother to mate with her.
“Its unusualness isn’t terribly unusual but it is exciting to witness – though less exciting and more worrying if you are sympathetic to mom and calf.”
Mr Milne said the calf “seemed fine” when the tour group and whales parted ways.
Brent and Min Milne bought Noosa Thriller Ocean Adventures, which was established in 2004, in early 2024. They operate three whale-watching tours daily from June to October and run ocean and dolphin adventure tours from November to June around the Noosa National Park coastline.
