With whale season approaching along the east coast, what better time to dive into the migration of the humpback and southern right whales.
Despite the long journey, stretching thousands of kilometres, these marine mammals’ migration is more than just a seasonal event. They were saved from extinction by a journey rich in ecological science, climate change, cultural importance, and conservation victories.
The Journey North
Every January, some 60,000 humpback whales set out on their yearly trip from Antarctica, travelling the 10,000 km round-trip across temperate waters to Queensland, where the warm weather facilitates calving and breeding.
Victoria’s Dolphin Research Institute’s Williamson Research fellow, Ella Hutchinson said the humpback whales migrate north each winter from the Southern Ocean feeding grounds to mate and calve.
“They migrate up to the subtropics to places like Queensland,” Ms Hutchinson said.
“In Victoria, we start seeing them migrate north from April to August, and then returning south until about November.”
In waters off Tasmania, the migration paths diverge. About 35,000 whales follow the western coastline beyond the Ningaloo Reef and the Margaret River coast, all the way to Exmouth and the Kimberley, while about 25,000 whales continue up the east coast to waters near Hervey Bay.
The Pacific Whale Foundation’s experts use pigmentation patterns to trace individual whale flukes by taking pictures of their undersides. With more than 6,900 whales recognised, their catalogue is the largest in Australia.
From Endangered to Iconic
During the whaling era, humpback whales were killed to almost extinction. Only 200 were thought to be left in Australian waters by the 1960s, when commercial whaling stopped. That figure has increased to more over 60,000 today.
Source: Pacific Whale Foundition.
This growth, about 11.5 per cent, is one of the world’s most successful marine conservation stories.
Climate Change and Shifting Patterns
While whale populations have grown, their habits are changing in ways scientists are still trying to understand.
Climate change is altering migration timings, feeding grounds, and calving behaviours.
ORRCA Research Club Committee member, Annie Post said whales are now starting to appear earlier in the year.
“We’ve observed that whales are appearing earlier in the year,” she said.
“They’re responding to environmental cues like sea temperature, but also using long-term memory to track prey availability.”
Ms Post points to tagging research from New Zealand that has revealed surprising deviations.
“Instead of heading directly south to the Antarctic, some whales are diverting westward, toward the Great Australian Bight and even up the west Australian coast,” Ms Post said.
“This suggests that the feeding grounds may be shifting due to ocean warming or ecosystem changes.”
These observations aren’t limited to the humpback whales.
“With southern right whales, we’re also seeing changes in distribution,” Ms Post said.
“It’s hard to tell whether this is an expansion or a reaction to environmental stress, but it’s definitely different from historical patterns.”
The Southern Right Whale: A Slower Recovery
While humpbacks thrive, the southern right whale continues a more fragile path to recovery.
Named by whalers as the “right whale to hunt”, due to its slow speed and high blubber content,southern rights were almost wiped out by the early 1900s. Today, their numbers remain low, and sightings are less common.
Source : WWF & Pacific Whale Foundition.
“Southern right whales stick closer to the southern coastlines and don’t travel as far north,” Ms Hutchinson said.
“In Victoria, we see them around Warrnambool and Portland, but their movements are much harder to predict.”
The data shows that the number of southern right whales has not recovered as quickly as that of humpbacks.
Source: WWF, Australian Wildlife Journeys & ORRCA
Southern right wales can be more difficult to examine because of their quieter demeanour, longer calving intervals, and lower reproductive rate.
Source: Scientific Reports
Victoria’s Emerging Whale Corridor
Victoria has traditionally been overlooked as a key whale habitat. That is starting to change.
“In Bass Strait, we’ve seen an increase in humpbacks stopping to feed,” Ms Hutchinson said.
“This is new. We’re seeing mothers and calves, and that suggests a behavioural shift.”
The Dolphin Research Institute recently published a white paper on these observations.
“If Bass Strait becomes a regular stopover, we’ll need to consider new marine protections,” Ms Hutchinson said.
“But we still need more data before we can determine whether this is a long-term trend or an anomaly.”
Technology and Citizen Science Combine
With limited resources, researchers have turned to technology and public support.
“You can’t go past biologging,” Ms Postsaid.
“Satellite tagging gives us incredible insights. Every time a whale surfaces to breathe, we receive location pings.”
In addition, platforms like Happy Whale, Wildlife Witness, and ORRCA’s reporting hotline, allows the public to upload photos and sightings.
“We rely heavily on citizen science,” Ms Hutchinson added.
“People reporting sightings can give us real-time data that helps monitor migration, health, and even entanglements.”
The Dolphin Research Institute’s PodWatch program trains school children and community groups to monitor local dolphin and whale activity.
Threats on the Horizon
Despite population growth, whales are facing new challenges.
The expansion of offshore wind farms raises questions about how turbine construction and underwater noise could affect migratory species.
“There isn’t enough data yet on the acoustic impacts of offshore wind farms on whale migration,” Ms Hutchinson warns.
“It’s something that needs long-term monitoring.”
Ship strikes, marine debris, plastic pollution, and ghost nets also pose significant threats.
In Victoria, groups like ORRCA work with the state’s WHALESVIC initiative to monitor and respond to entangled animals.
Whales as Ocean Sentinels
Both Ms Post and Ms Hutchinson agree that whales serve as indicators of ocean health.
“What happens to whales reflects what’s happening across the ecosystem,” Ms Host said.
“From krill availability to sea temperature and noise levels, it all ties in.”
With whale season underway along the east cost, the public is being encouraged to observe and report sightings, in an effort to support research organisations.
Whether it’s a breach off the Sydney coastline or a mother nursing her calf in waters off Hervey Bay, each sighting is a piece of a larger puzzle, one that researchers, volunteers, and citizens are working together to solve.
