Australians scientists have captured video footage of a rare white southern right whale calf off the coast of Western Australia.
Right whales, so named because, unlike humpback whales, they float when harpooned, were hunted to near extinction. Their numbers are still small but scientists have started to see an increase for the first time in 40 years.
There are believed to be around 3000 right whales in Australia, making them relatively vulnerable.
White whales of any variety are rare. There is Migaloo, a humpback whale which travels the east coat of Australia each year, and in the early 1970s there was a confirmed sighting of a white sperm whale in the Southern Ocean.
The researchers from the Cetacean Research Unit at Murdoch University found the white calf immediately after they launched drone flights in Flinders Bay off Augusta in southern Western Australia from July 25.
Here’s the footage (the white whale appears at 1.43):
From the photos taken by the drone, the scientists estimate the white calf was 6.2 metres long when they first saw her and grew to 6.9 metres 16 days later.
That’s a mean growth rate of 4.4cm a day.
“We were very excited to come down to Augusta and photograph the calf from the air with our drone, and also to tag its mother to look at her behaviour,” Dr Fredrick Christiansen at Murdoch University told Business Insider.
“Funny enough, the white calf and its mother were the first whales we encountered in Augusta and also the last pair we saw at the end of the fieldwork season.
“The pair stayed relatively close to the town of Augusta and could therefore be viewed by tourists onboard the whale watching companies operating out of there.”
The video from the drones helps the researchers to measure and assess body size and health.
Right whales are large baleen whales, which sift their food, and grow to about 15 metres in length and weigh 60 tonnes. Calves are between 5 metres and 6 metres in length at birth.
The researchers assessed acoustic communications, ambient noise, calf suckling rates and body condition.
The team hopes to better understand the behaviours of the whales and how human activities may influence this.
Professor Lars Bejder says little is known about the fine-scale movements — depth, pitch and roll — and habitat-use of southern right whales on their breeding and calving grounds in Australia.
“We need to know more about the ambient ocean noise in these regions and the extent to which southern right whales will be exposed to increased noise derived from human undertakings,” says Professor Bejder.
They also used hand-held poles from small boats to attach digital acoustic recording tags (DTAG) to seven whales.
“The DTAG measures and records the depth and temperature of the water, and the swimming orientation in three-dimensions of the tagged animal,” says Professor Bejder.
“The tag also recorded sound, which is sufficient for measuring sounds both made by boats and heard by the whales.”