Big season for whales

Doug Coughran out spotting whales.
Doug Coughran out spotting whales.

‘I think it will be a big season as we have a lot of animals now, and the migration kicked off in the first week in May, when often it’s the last week of May,’ Department of Parks and Wildlife senior marine wildlife officer Doug Coughran said.

Commercial whaling reduced humpbacks in WA waters to less than 800 but since protection in 1963, numbers have risen about 10 per cent annually, making the State’s estimated 30,000 humpbacks one of the world’s fastest-growing sub-populations.

The mammals, famous for underwater singing and breaching, spend summers feeding on Antarctic krill directly south of WA, congregating on WA’s south coast by late autumn before mature and pregnant whales head north to calve, leaving sub-adult animals waiting for the return migration in spring.

Since May, an unusually high number of five humpbacks washed up dead between Albany and Coral Bay.

Mr Coughran said most were immature and underweight, which could indicate pressure on food sources caused by the growing population or a return to a pre-whaling phenomenon of many more young whales not feeding enough before their first migration.

Sick humpbacks often travel closer to shore than the healthy, faster migrants passing near Rottnest Island, while females with calves may come closer to avoid aggressive males.

Mr Coughran said a ‘starving’ 6m-7m yearling was about half its expected 10-15 tonne weight when a great white shark followed it close to Perth beaches, before the whale washed ashore at Alkimos Beach last month.

About 3000 slow-swimming southern right whales, brought to near extinction by whaling, were usually healthy when seen near south coast shore breaks, resting and protecting calves before Antarctic voyages.

Nets threaten migrating whales and 32 entanglements were recorded last year, an increase from 2012.

Mr Coughran said boats should stay 100m from a whale and disengage motors or move slowly away if approached, while swimmers, surfers, kayakers and stand-up paddle boarders were at ‘great risk’ of injury and death from a 45,000kg whale.