This north-south migration occurs every year, but the whales can still surprise us. Thanks to a taxpayer scientist and his drone, humpback whales were seen feeding in a mass-produced group and"bubble-net feeding" off the New South Wales coast this past year.
As my new study paper affirms this a huge deal for two reasons: it is just the next time a superb group of humpbacks has been observed at the southern hemisphere (a first for Australia) and also the first-time bubble-net feeding has been seen in Australia.
So what's bubble-net feeding, and are such observations so important?
Blowing bubbles, catching krill
Bubble-net feeding is when whales intentionally blow bubbles from their noses to encircle their own meals --krill and fish--such as a net, concentrating their prey into a tight ball. Then, the whale or group of whales float together from beneath, grow to the surface opening their mouths, and gulp their prey up.
It remains a puzzle as to why the whales feed this manner and the way they learned to do it.
2020 was a year filled with events that are unprecedented, and the humpback whales certainly didn't disappoint.
Humpback whales in this eastern Australian people are often observed lunge feeding on their side, or feeding below the surface. Bubble-net feeding, on the other hand, is largely recorded in some Northern Hemisphere inhabitants .
But we know that there are individual whales in the eastern humpback people who bubble-net feed from temperate waters. This usually means the unique behaviour in Australian waters might have evolved independently, or via cultural transmission (learning new behaviours from different whales).
The drone footage and observations made in September from whale-watching ships was the first to record bubble-net feeding. To increase the excitement, citizen scientists also documented bubble-net feeding behaviour farther south of Tasmania a month later.
Using stills from the September drone footage, an estimated 33 humpback whales can be observed feeding in the exact same moment. Regrettably, it is not known exactly what the whales were feeding on.
In reality, the only other time that a mass humpback feeding occasion was seen from the Southern Hemisphere was away South Africa at 2011 (this now happens regularly there). This was the first time the expression"super group" was used to describe a set of 20 or more whales feeding this way.
But why are they feeding 'breeding waters' anyway?
The majority of the west humpback whale population spends the summer months feeding in Antarctic waters.
They forego feeding for love--humpbacks can go for weeks without eating, relying instead on energy reserves in order to replicate. Animals that do so are known as capital breeders.
On the way, they sometimes take a"pit-stop" on parts of Australia's east shore to nourish .
It was originally thought this population never fed along the migratory route. However, we understand they do now to supplement their energy intake as they migrate.
So are such observations important?
Whales play significant an important part in the ecosystem of the ocean because they feed in 1 area and poo in a different.
This action--known as the"whale pump"--transfers nutrition around the sea. Their poo feeds tiny organisms, such as plankton, which can be eaten by krill, then eaten by whales.
Seeing these super group feedings highlights changes in our marine environment we might not have been aware of.
1 possible explanation for this behaviour could be favorable ecological conditions. A combination of perfect water temperatures and nutrition may have resulted in an abundance of food, which found substantial numbers of humpback whales feeding in the same area.
Regardless, it is important to see how changes in the marine environment affect the extent humpback whales depend on feeding chances in their migratory route.
This can help to predict the way that whale populations respond to future fluctuations in the ocean. This includes climate change, which will warm sea temperatures and change when and in which the victim of humpback whales can be located. Consequently, humpback whales will also move to different places.
One thing, at least, is clear: more eyes land and sea via citizen science will provide a valuable chance to record such exciting future occasions. So keep your eyes peeled for whales this year, and be sure to inform a scientist should you see something unexpected.
