Shortcuts / 01 June 2023

The annual whale migration

If you live anywhere along the east or west coast of Australia, chances are you might have heard it’s whale watching season, when nature’s biggest mammals head north in a mass migration. So in this Squiz Shortcut, we look at what a whale migration is, how whales are faring with so much concern about our oceans, and where and when you can get to see all the action.

Moving north for the summer, eh? Whales have the right idea…
Yep, they collectively get together and abandon Antarctica every year and spend at least a few months away in warmer climates.

But it’s not just for a suntan?
Not quite… Krill is a main food source for whales, which is why they love hanging out in the waters around Antarctica. They gorge over summer and get that good layer of whale blubber, then they head off north, along both the east and west coasts of Australia.

Why the mass migration?
Their goal is to mate when they get up to the Great Barrier Reef or the Kimberly coast in Western Oz. There might be a bit of opportunistic feeding along the way but basically, they are on a mission to get there, so they really rely on their fat stores when they are heading north.

What happens after that?
So get this – the pregnant females don’t just hang around all year to give birth – they then swim thousands of kilometres back to Antarctica to start feeding up on those krill again.

That’s some dedication to krill…
Sure is. So humpbacks are pregnant for about 11.5 months, swim 5000km north to get pregnant, back again 5000km to feed up during pregnancy, then they has time to turn around and do another 5000km to go north to give birth!

Yikes… Why not just give birth around Antarctica?
It’s likely the calves couldn’t survive the temperatures because they don’t have the fat stores. In places around the Great Barrier Reef, mothers and calves generally remain in shallow, sheltered waters where the calves can gain the weight they need to get back to the feeding grounds.

While we’re talking babies, how are whale populations going?
So a group called ORRCA do an annual census to track whale numbers, and they’ve recorded a gradual increase in numbers over the past 21 years. Researchers reckon about 35,000 whales move up the east coast, and the same number goes up the coast of Western Oz.

That’s a lot of whales…
Yep, and it’s pretty extraordinary considering they’d almost been hunted to extinction. When whaling was banned in the Southern Hemisphere in 1963, humpback whale numbers were thought to be as low as 100.

Why did people hunt whales?
They were considered very valuable animals, particularly in the 1800s. Their blubber was melted down to be used as oil for lamp fuel, candles and a base for soaps. Baleen or whalebone was pretty common in women’s corsets and some everyday items like umbrellas and children’s toys.

But things aren’t all hunky dory now?
Nope, conservationists are worried warming ocean temperatures will reduce the krill population and affect whale fertility. They’re also concerned about pollution from plastic and chemicals from things we produce on land. Overfishing is another big one – whales can get caught in the big nets cast out by fishing trawlers.

Back to the annual migration – are there any other breeds to keep an eye out for?
There are dozens – the minke whale, the sperm whale, the fin whale, and the blue whale, which can measure up to 30 metres long. There’s also the southern right whale – it really is a majestic creature if you ever get the chance to spot one.

What does it look like?
You can spot them by the white and grey growths on their head. There were up to 70,000 of them in the 1700s but their numbers have only recovered to about 3,500 in the Southern Hemisphere so far. They don’t usually go as far north as the humpbacks – they just move between the southern coastline of Australia, up as far as Byron Bay.

Where are the best spots to see these majestic creatures?
The great thing about whale watching is you don’t have to go on a boat tour. It’s pretty special if you get to see them close up but there are so many vantage points and they can come really close to the shoreline.

So pick a headland on the east or west coast?
Exactly – locals usually know the best spots. There have been sightings from Batemans Bay to Port Macquarie to Mandurah in WA. They are well and truly on the move.

But I assume you shouldn’t get too close?
That’s right, authorities don’t want boats or drones getting right up in their grill, and there are really strict rules around it. Marine Rescue NSW says boaties must stay 100 metres away and if there’s a calf, that increases to 300 metres. Drone laws are different everywhere but in Western Oz, you aren’t allowed to get closer than 60 metres.

Which is probably safest for everyone…
Yep, whales are big animals – a pregnant humpback can weigh 200 tonnes. So it’s best to keep a safe distance.

I might stay on the shore…
And don’t forget you can see them now or when they come home from up north, which is usually between September to November.

Squiz recommends:

Underwater vision of the Humpback whale, narrated by the one and only Sir David Attenborough

ORCCA census day information

Squiz Shortcuts - A weekly explainer on a big news topic.

Get the Squiz Today newsletter

It's a quick read and doesn't take itself too seriously. Get on it.