THE humpback highway is becoming more congested, with a record number of whales expected on their annual migration.

With the whale-watching boat tour season due to kick off this weekend, National Parks and Wildlife whale spokesman Lawrence Orel said up to 20,000 giants of the deep would pass along the coast in the next few months — a far cry from the days when the magnificent beasts were almost wiped out by whaling.

Smiling for his first baby photos, this humpback calf delighted whale watchers when he popped his head up just 20m from their boat in Sydney Harbour.

The curious calf launched itself in the air more than 20 times as if wanting a good look at its human admirers.

Photographer Jonas Liebschner snapped these amazing images of the young whale, seemingly smiling and in many cases looking directly at passengers on the Whale Watching Sydney cruise, as its mum watched on.

Whales, it seems, just do not want to listen. Even when it is for their own good.

A study on the effectiveness of commercial whale alarms in deterring the ocean giants from fishing nets and lines measured no response from migrating humpback whales.

Rob Harcourt, the research leader from Macquarie University, said he was surprised by the research findings because the devices had been shown to work in other parts of the world.