Queensland researchers say whale watchers have reported fewer sightings this migration season on the east coast.
- Fewer humpback whale sightings near the coast this season
- Researchers Say East Australian Current Influences Whale Behavior
- Whale-watching tour operators say ‘peak’ migration south is underway
Australia’s east coast is known as the “humpback road” in winter and spring as whales migrate north to breed.
But experts say there has been less traffic near popular beaches this year.
Griffith Center for Coastal Management researcher Dr Olaf Meynecke said the season had been unusual with whales staying further offshore.
“Very different from the last three years at least, as the whales have migrated quite a distance offshore,” Dr Meynecke said.
“A lot less is happening near the coast.”
Fewer entanglements in shark nets
Dr Meynecke said the southward migration was now underway, with whales and their calves making their return journey.
He said the pods were more often spotted 10-15km offshore.
“Of course, moms and little ones usually come near the shore to rest.
“But there are not as many as last year and certainly not as many newborns.
“It’s been a very different season.”
Are whales looking for Nemo?
Dr Maynecke said the East Australian Current (EAC) – made famous by a certain clownfish – serves as a navigation tool for migrating humpback whales.
He said this year the EAC was further offshore, which might explain why the whales were too.
Bureau of Meteorology ocean analyst Lucinda Matthews said the EAC appeared to be weakening along the Gold Coast in August and moving slightly eastward.
The EAC transports hot water south from the tropics.
“This is significantly warmer water compared to what you would find at the latitude of Sydney, for example,” Ms Matthews said.
“It is quite nutritionally poor itself, but current flow generates ocean eddies and creates conditions that increase water productivity further south.”
The interaction between the coast, the current and the northerly winds can generate upwellings that bring deep, cold and nutrient-dense water to the surface.
These conditions can provide feeding opportunities for migrating whales.
“Without providing the nutrition itself, it (the EAC) helps pull nutrition in where it wouldn’t otherwise come from,” Ms Matthews said.
“If you didn’t have those northerly winds, you still get steep temperature gradients just because that warm current flows through the cooler surrounding waters.
“These thermal fronts and current-driven mixing are also very active in a biological sense.”
“Close Encounters” with Boats
Seaworld Cruises estimated that 35,000 humpback whales migrated this season.
The group’s brand manager, Lauren Horner, said her boat crews had experienced a similar number of whale encounters compared to previous years.
“What we tend to see at this time of year is all these moms and their new little babies coming to the bay,” Ms Horner said.
“They usually hang around for four to seven days at a time.
“You see all these very close encounters with ships.
Despite the lack of tourists between states and changes to the whale migration route this year, tour operators are hoping for a bumper school vacation period.
“We miss our guests from Sydney and Melbourne; we would love to welcome them here,” Ms Horner said.
“But we’re kind of seeing strong adoption in the local market.”
Hopefully they see a lot more whales too.