Sharks having a whale of a time?

So perhaps the whales have not created a shark migration.

Perhaps they've supercharged an existing one.

A great white following mullet or salmon still has to hunt them. A dead humpback is something quite different: a stationary blubber buffet, potentially tens of tonnes of meat and fat concentrated in one place and available to multiple large sharks.

A shark already travelling the coastal food highway now has access not just to moving schools of fish, but to the occasional carcass carrying an extraordinary quantity of Antarctic energy.

And there is an intriguing bit of circumstantial evidence.

NSW white-shark attacks averaged about 2.1 per year between 2000 and 2014.

From 2015 to 2021 they averaged 5.3.

Exclude the extraordinary 10 attacks in 2015 and the 2016-21 average is still 4.5, more than double the earlier rate.

Even more interestingly, the NSW shark-meshing program, which has been operating at broadly the same beaches for decades, reported that white-shark catches after 2015/16 were consistently around three to five times higher than during the preceding period.

That doesn't prove there are three to five times as many great whites. They may simply be spending more time close to the NSW coast.

But that possibility is just as interesting.

White sharks are extraordinarily mobile. Their seasonal movements overlap substantially with whale migration and with the seasonal migrations of large schooling fish.