The male humpback whales, known as "bachelors", are beginning their migration to the Antarctic for feeding, having spent the winter breeding in warmer, tropical waters.

According to Lawrence Orel, from the NSW National Parks and Wildlife Service,  similarities exist between the romantic courting rituals of these aquatic mammals, and those of the popular reality TV series. But, unlike the tedious waiting games and rose ceremonies that the TV contestants are subject to, the female whales are very much in charge of their mate selection.

The east coast humpback whale population had experienced a "dramatic and encouraging recovery" over the past 50 years since the whaling of humpback whales ceased, Orel said. This year the NPWS had observed a population of around 20,000 whales passing through the NSW coastline on their migration route.

"It's a great time of year for whale watching," Geoff Ross, co-ordinator of the marine fauna program at the NPWS, said, "with the opportunity to spot females travelling with their newborn calves." Botany Bay, Sydney Harbour and Watson's Bay are among his top spots for spotting the migrating mammals.

"Females with calves are less tolerant than when they are on their northern migration," Ross warned, so recreational boaters, skippers and mariners should slow down and exercise extra caution when entering and leaving bays.

"To protect the community and the whales, make sure they adhere to the approach distances," Ross said, "Three hundred metres  for a whale with a calf, and 100 metres when there is no calf present."