As winter sets in, a remarkable migration is taking place along Australia’s coastlines

Welcome to whale season. Get to know these iconic visitors from the Southern Ocean, meet the people who study them, and find out how you can become a citizen scientist.

Within minutes of leaving Sydney Harbour, Vanessa Pirotta spots a whale gliding through the waters beyond the city’s towering sandstone cliffs.

“It’s a blow, we’ve got whales!” she shouts.

Water droplets from the whale rise into the air, as the dark shadow of the whale’s back sinks under the surface.

As the days grow shorter and colder, and icy winds signal winter is on its way, humpback whales (Megaptera novaeangliae) and southern right whales (Eubalaena australis) begin their annual migration to northern breeding grounds.

Standing on the deck of a boat with a camera slung about her neck, Dr Pirotta is using a drone to collect samples of humpback whale snot, which provide a snapshot of the animal’s health and the ocean they swim in.

Long-term information gathered by whale watchers, boaties, wildlife photographers and tour operators can also help scientists learn more about these majestic Southern Ocean animals and help protect their habitat as they recover from decades of exploitation.

Growing up to the size of a bus, humpbacks have a small dorsal fin on their grey-coloured back, and light-coloured markings under their long pectoral fins, belly and tail. 

In the east,  humpbacks hit the Victorian coast in April and turn right on their journey up the coast of NSW, making a beeline towards the Great Barrier Reef.

In the west, humpbacks start to skirt around the south-west coast of Western Australia in late May.

The western humpbacks are heading up to their calving grounds, which extend from the turquoise waters of Shark Bay to the ochre cliffs of the Kimberley.

After a couple of months, the whales make their way back down south at a more leisurely pace along both coasts with calves in tow, stopping close to shore to rest and play. 

Southern right whales are larger and darker than humpbacks, have a much shorter paddle-like pectoral fin, and are the only species of large whale that doesn’t have a dorsal fin.

They also have bright white patches called callosities on their heads that are unique to every individual.

About 5 per cent of southern right whale calves are white, with their colour changing to a light pinkish-grey over time.

During winter, southern right whales head to the calm waters along the coast of  Victoria, South Australia, and Western Australia.

The females will spend up to four months in these areas with their newborn calves.

Many of these whale nurseries are former whaling stations.

Humpbacks and southern right whales were  among several species of whales slaughtered for their oil, blubber, bones and plates of keratin in their mouths known as baleen, at whaling stations right around Australia.

Whaling was banned in 1978. Today, all species are listed as protected but they are affected by environmental pressures such as ship strike, entanglement in fishing gear, noise in developed areas, and changes to climate and ocean conditions along their route.

Source: ABC News