Young humpbacks exposed to danger with shifting births

The Advertiser

23-05-2025

Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.
A recent UNSW-led study has documented humpback calves being found more than 1500km further south than their assumed birth zone.
Lead author Jane McPhee-Frew was working as a skipper on a whale-watching boat in Newcastle in 2023 when she spotted a new calf.
The sighting piqued her interest, sparking a citizen science project that accumulated 200 calf sightings.
They received reports from the bottom of Tasmania, the southernmost part of WA and New Zealand's south island.
Ms McPhee-Frew said the observations suggested humpbacks might have more complex behaviour than previously thought and much could still be learned about their migration.
Calving in cooler waters had been documented in first-hand evidence and whaling log books from the early 20th and 19th centuries, she said.
The recent data could be observations of an existing behaviour made more visible as the species' numbers recovered from the bring of extinction, Ms McPhee-Frew added.
Griffith University marine scientist Olaf Meynecke said the number of calves seen in cooler waters was definitely trending upwards.
"The number of calves in the last few years just on the Gold Coast ... we have just not seen those numbers, say 10 years ago," he said.
Some humpbacks' migratory habits were also shifting and they were not going all the way to their usual Great Barrier Reef end point.
"What we do see is an earlier (migration), likely to do with an earlier sea ice melt in the Antarctic and (faster) warming in Antarctica," Dr Meynecke said.
"(We've also seen) more intense feeding outside the traditional feeding grounds, just in Australian waters around Victoria, Tasmania and the southeast coast of NSW."
Calving further south could be in response to changes in food availability, creating a strategy among females to avoid competition in northern feeding grounds, Dr Meynecke said.
"We don't know how much further north mothers migrate with their newborn calves and what effect this has on the newborn," he said.
Calves born at more southerly locations might traverse extra kilometres off Australia's coasts, exposing them to greater risk of entanglement or boat collisions.
"The pattern we're seeing is mother whales with calves travelling through some of the busiest shipping lanes and urbanised regions," Ms McPhee-Frew said.
NSW National Parks and Wildlife Service's Adelaide Dedden said boat users needed to be aware of migrating calves.
"People need to be aware that calves are being seen not just on the southern migration but also on the northern one," she said.
Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.
A recent UNSW-led study has documented humpback calves being found more than 1500km further south than their assumed birth zone.
Lead author Jane McPhee-Frew was working as a skipper on a whale-watching boat in Newcastle in 2023 when she spotted a new calf.
The sighting piqued her interest, sparking a citizen science project that accumulated 200 calf sightings.
They received reports from the bottom of Tasmania, the southernmost part of WA and New Zealand's south island.
Ms McPhee-Frew said the observations suggested humpbacks might have more complex behaviour than previously thought and much could still be learned about their migration.
Calving in cooler waters had been documented in first-hand evidence and whaling log books from the early 20th and 19th centuries, she said.
The recent data could be observations of an existing behaviour made more visible as the species' numbers recovered from the bring of extinction, Ms McPhee-Frew added.
Griffith University marine scientist Olaf Meynecke said the number of calves seen in cooler waters was definitely trending upwards.
"The number of calves in the last few years just on the Gold Coast ... we have just not seen those numbers, say 10 years ago," he said.
Some humpbacks' migratory habits were also shifting and they were not going all the way to their usual Great Barrier Reef end point.
"What we do see is an earlier (migration), likely to do with an earlier sea ice melt in the Antarctic and (faster) warming in Antarctica," Dr Meynecke said.
"(We've also seen) more intense feeding outside the traditional feeding grounds, just in Australian waters around Victoria, Tasmania and the southeast coast of NSW."
Calving further south could be in response to changes in food availability, creating a strategy among females to avoid competition in northern feeding grounds, Dr Meynecke said.
"We don't know how much further north mothers migrate with their newborn calves and what effect this has on the newborn," he said.
Calves born at more southerly locations might traverse extra kilometres off Australia's coasts, exposing them to greater risk of entanglement or boat collisions.
"The pattern we're seeing is mother whales with calves travelling through some of the busiest shipping lanes and urbanised regions," Ms McPhee-Frew said.
NSW National Parks and Wildlife Service's Adelaide Dedden said boat users needed to be aware of migrating calves.
"People need to be aware that calves are being seen not just on the southern migration but also on the northern one," she said.
Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.
A recent UNSW-led study has documented humpback calves being found more than 1500km further south than their assumed birth zone.
Lead author Jane McPhee-Frew was working as a skipper on a whale-watching boat in Newcastle in 2023 when she spotted a new calf.
The sighting piqued her interest, sparking a citizen science project that accumulated 200 calf sightings.
They received reports from the bottom of Tasmania, the southernmost part of WA and New Zealand's south island.
Ms McPhee-Frew said the observations suggested humpbacks might have more complex behaviour than previously thought and much could still be learned about their migration.
Calving in cooler waters had been documented in first-hand evidence and whaling log books from the early 20th and 19th centuries, she said.
The recent data could be observations of an existing behaviour made more visible as the species' numbers recovered from the bring of extinction, Ms McPhee-Frew added.
Griffith University marine scientist Olaf Meynecke said the number of calves seen in cooler waters was definitely trending upwards.
"The number of calves in the last few years just on the Gold Coast ... we have just not seen those numbers, say 10 years ago," he said.
Some humpbacks' migratory habits were also shifting and they were not going all the way to their usual Great Barrier Reef end point.
"What we do see is an earlier (migration), likely to do with an earlier sea ice melt in the Antarctic and (faster) warming in Antarctica," Dr Meynecke said.
"(We've also seen) more intense feeding outside the traditional feeding grounds, just in Australian waters around Victoria, Tasmania and the southeast coast of NSW."
Calving further south could be in response to changes in food availability, creating a strategy among females to avoid competition in northern feeding grounds, Dr Meynecke said.
"We don't know how much further north mothers migrate with their newborn calves and what effect this has on the newborn," he said.
Calves born at more southerly locations might traverse extra kilometres off Australia's coasts, exposing them to greater risk of entanglement or boat collisions.
"The pattern we're seeing is mother whales with calves travelling through some of the busiest shipping lanes and urbanised regions," Ms McPhee-Frew said.
NSW National Parks and Wildlife Service's Adelaide Dedden said boat users needed to be aware of migrating calves.
"People need to be aware that calves are being seen not just on the southern migration but also on the northern one," she said.
Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.
A recent UNSW-led study has documented humpback calves being found more than 1500km further south than their assumed birth zone.
Lead author Jane McPhee-Frew was working as a skipper on a whale-watching boat in Newcastle in 2023 when she spotted a new calf.
The sighting piqued her interest, sparking a citizen science project that accumulated 200 calf sightings.
They received reports from the bottom of Tasmania, the southernmost part of WA and New Zealand's south island.
Ms McPhee-Frew said the observations suggested humpbacks might have more complex behaviour than previously thought and much could still be learned about their migration.
Calving in cooler waters had been documented in first-hand evidence and whaling log books from the early 20th and 19th centuries, she said.
The recent data could be observations of an existing behaviour made more visible as the species' numbers recovered from the bring of extinction, Ms McPhee-Frew added.
Griffith University marine scientist Olaf Meynecke said the number of calves seen in cooler waters was definitely trending upwards.
"The number of calves in the last few years just on the Gold Coast ... we have just not seen those numbers, say 10 years ago," he said.
Some humpbacks' migratory habits were also shifting and they were not going all the way to their usual Great Barrier Reef end point.
"What we do see is an earlier (migration), likely to do with an earlier sea ice melt in the Antarctic and (faster) warming in Antarctica," Dr Meynecke said.
"(We've also seen) more intense feeding outside the traditional feeding grounds, just in Australian waters around Victoria, Tasmania and the southeast coast of NSW."
Calving further south could be in response to changes in food availability, creating a strategy among females to avoid competition in northern feeding grounds, Dr Meynecke said.
"We don't know how much further north mothers migrate with their newborn calves and what effect this has on the newborn," he said.
Calves born at more southerly locations might traverse extra kilometres off Australia's coasts, exposing them to greater risk of entanglement or boat collisions.
"The pattern we're seeing is mother whales with calves travelling through some of the busiest shipping lanes and urbanised regions," Ms McPhee-Frew said.
NSW National Parks and Wildlife Service's Adelaide Dedden said boat users needed to be aware of migrating calves.
"People need to be aware that calves are being seen not just on the southern migration but also on the northern one," she said.