Whales, dolphins, swarms of krill spotted off Vic coast near Portland
Updated
A blue whale has been spotted swimming with a pod of dolphins off Victoria's south-west coast as an expert says large amounts of krill point to a good year for whale-watching ahead.
An aerial survey by the Blue Whale Study, an independent research organisation, spotted 11 pygmy blue whales as well as swarms of krill near Portland last week.
The survey involved scouring the coastline for the mammals and their food source as the upwelling season begins.
Upwelling is a process driven by wind movements when cold, nutrient-rich water wells up to the surface.
Dr Pete Gill from the Blue Whale Study said the process was important for the tiny crustaceans on which the blue whales feed.
"Krill are little crustaceans that grow to about 2 centimetres but they swarm in billions, and they provide a really rich food supply to these largest of animals ever," he said.
"The blue whale has this enormous mouth that lets them gulp as much as 80 or 100 tonnes of water and krill and then they filter out the krill and swallow it.
"It's really important for blue whales to have a lot of food available, and this year for the first time in many years we're seeing a lot of krill."
Photos shared on social media show one whale swimming with a pod of dolphins, and another emerging from beneath a cloud of krill.
Dr Gill said that was a particularly rare sighting that bodes well for the year ahead.
"The whale is just quietly swimming under the krill and making no attempt to gobble it up," he said.
"If the blue whale were hungry it would be smashing that swarm of krill. It would be lunging into it with its huge mouth open trying to gobble as much as it could.
"The fact that that whale is just casually surfacing under that big fat swarm of krill indicates that because there's so much food around these whales have fed well."
Fears over effect of climate change
The researchers have been surveying the area, known as the Bonney upwelling feeding ground, since 1998.
Dr Gill said they have had an extended period of weak upwelling, and have spotted some skinny whales.
"When it happens year after year you start to wonder if there's some change in the system … whether it's going to bounce back," he said.
"We are dealing now with climate change which has very significant effects on the ocean overall; we don't know what the effect is going to be on this upwelling system."
The aerial survey has made them hopeful it will be a year of plenty for the whales and other marine species.
The study will continue as the season goes on, with researchers taking to the water in a small boat.
Although the pygmy blue whale grows up to 25 metres in length, Dr Gill said it could be difficult to find them.
"For such an enormous animal they can be incredibly hard to find — no matter how big a blue whale is the ocean is just vastly larger," he said.
"They are greyhounds of the sea that can move rapidly from one feeding area to another.
"They can just give you the slip unbelievably easily."
Topics: animals, human-interest, mammals---whales, animal-science, science-and-technology, portland-3305, vic
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