Observable humpback whale numbers making the annual journey along Western Australia's coast fell 60% this year, with researchers saying low numbers are being reported across the Southern Hemisphere.
Observers recorded far fewer whales on the annual journey from the Southern Ocean to WA's northern waters, with less calves sighted and more strandings and entanglements along the coast. Mothers with calves were also scarce on the southern migration after birthing off the north Kimberley.
"It certainly has been an odd year for the humpback whales," Geographe Marine Research team leader Capri Jolliffe said. Marine Scientist Olaf Meynecke described the season as "strange."
"Reports around the Southern Hemisphere, from different populations of humpbacks, are all telling the same story of low numbers," said Dr Meynecke, a Griffith University researcher. He said earlier sea ice melts meant the whales were spending less time in their feeding grounds. Lower food supplies due to changing krill populations and phytoplankton blooms were also having an impact.
"We had mums looking quite thin," Dr Meynecke said. "You can see their fat reserves have been depleted and that's concerning because they need enough milk for their calves. We've had strandings of unhealthy whales, seen unfit whales."
Four dead whales have washed ashore during November and October along popular beaches in WA.
Veteran Broome whale watcher Cameron Birch said he travelled much further than normal from the coast to find whales for tourists. "We went nearly twice as far out, 10 or 12 nautical miles offshore," he said. "And definitely less on the water, instead of interacting with 10 or 15 whales a day, it might only be two or three."
But Mr Birch believes the drop-off is not yet cause for alarm. "Over the last 25 years we've seen this cyclic seasonality — we'll have amazing numbers for a few years, then they'll thin out," he said. "And we've had times, say three years in a row, of low numbers then bang; they just bounce back again. So until we start to see a pattern, I wouldn't be concerned."
Dr Meynecke said whale entanglements had risen to 60 this year across Australia, a jump of 20%. But he feared for their survival rate and that there could be many more unreported entanglements. "There's a tragedy behind every number, but what are the grey numbers? They could be double," he said.
Dr Meynecke said ongoing research was vital, as humpbacks were often a bellwether for other whale populations. "If humpback whales start to struggle then all the other large whales start to struggle," he said. "They're all signals telling us they're experiencing change."
Analysis
Why This Matters
- Humpback whales are a key indicator species for ocean health; a sustained decline could signal broader ecosystem shifts.
- WA's whale-watching tourism, a significant economic activity especially in Broome from June to October, is already seeing fewer encounters per trip.
- The reported rise in entanglements and strandings suggests immediate welfare and conservation challenges.
Background
Humpback whales migrate each year from the Southern Ocean to the warm waters off northern Australia to breed. Along the WA coast, the migration is a major tourist attraction and a long-studied natural phenomenon. Whale watchers and researchers have documented the migration for decades, and some observers note natural population cycles, with good years and lean years.
Key Perspectives
Capri Jolliffe (Geographe Marine Research team leader): "It certainly has been an odd year for the humpback whales."
Dr Olaf Meynecke (Griffith University marine scientist): Described the season as "strange" and says reports from humpback populations across the Southern Hemisphere all tell the same story of low numbers. He links the drop to earlier sea ice melt and reduced food supplies, and warns that humpback struggles signal trouble for other large whale species.
Cameron Birch (veteran Broome whale watcher): Says he travelled twice as far offshore to find whales and saw fewer animals, but believes the decline is part of a natural 20-25 year cycle and is not yet cause for alarm.
What to Watch
- Whether low whale numbers persist for another year or more, which would distinguish a natural cycle from a long-term trend.
- Further data on unreported entanglements and the condition of whales on migration in the next season.
- Southern Hemisphere humpback population surveys from other regions to confirm if the pattern is widespread.
Checked
12 claims in this story checked against 1 source: 12 supported.
Show each claim
- SupportedObservable humpback whale numbers on the annual WA migration fell 60% this year.Just In: “Observable whale numbers making the annual journey from the Southern Ocean to WA's northern waters dropped by 60 per cent this year.”
- SupportedResearchers said low humpback numbers were being reported across the Southern Hemisphere.Just In: “"Reports around the Southern Hemisphere, from different populations of humpbacks, are all telling the same story of low numbers," Dr Meynecke said.”
- SupportedEarlier sea ice melts meant whales spent less time in their feeding grounds.Just In: “The Griffith University researcher said the earlier sea ice melts meant the whales were spending less time in their feeding grounds.”
- SupportedLower food supplies linked to changing krill populations and phytoplankton blooms were having an impact.Just In: “At the same time, lower food supplies due to changing krill populations and phytoplankton blooms were also having an impact.”
- SupportedBirch said the drop-off was not yet cause for alarm.Just In: “But Mr Birch believes the drop-off is not yet cause for alarm.”
- SupportedJolliffe said, “It certainly has been an odd year for the humpback whales.”Just In: “"It certainly has been an odd year for the humpback whales," Geographe Marine Research team leader Capri Jolliffe said.”
- SupportedMeynecke said, “Reports around the Southern Hemisphere, from different populations of humpbacks, are all telling the same story of low numbers.”Just In: “"Reports around the Southern Hemisphere, from different populations of humpbacks, are all telling the same story of low numbers," Dr Meynecke said.”
- SupportedMeynecke said, “We had mums looking quite thin.”Just In: “"We had mums looking quite thin," Dr Meynecke said.”
- SupportedFour dead whales washed ashore along popular WA beaches during November and October.Just In: “Four dead whales have washed ashore during November and October along popular beaches in WA.”
- SupportedBirch said, “We went nearly twice as far out, 10 or 12 nautical miles offshore.”Just In: “"We went nearly twice as far out, 10 or 12 nautical miles offshore," he said.”
- SupportedBirch said that instead of interacting with 10 or 15 whales a day, they might see only two or three.Just In: “"And definitely less on the water, instead of interacting with 10 or 15 whales a day, it might only be two or three."”
- SupportedMeynecke said entanglements had risen to 60 this year across Australia, a 20% increase.Just In: “Dr Meynecke said whale entanglements had risen to 60 this year across Australia, a jump of 20 per cent.”
