From Antarctic history to animal behaviour! This was really exciting – seeing two Humpback Whales bubble netting. But what is bubble netting?
Humpback Whales are baleen whales, which means that instead of teeth they have a sieve of baleen (made of keratin, like fingernails). When they eat, they take huge mouthfuls of water, and then pump the water out through the baleen, which traps any plankton, krill, or small fish that they’ve gulped up with the water. It’s an effective way of getting as much food as possible out of every mouthful, which you need when you are up to 14 meters long!
Bubble netting is a way of concentrating prey (krill, plankton, fish) in a small area, so that each mouthful yields more nutrition. What the whales do is move in a tight circle underneath the prey and release bubbles through their blowhole. This drives the prey into an area confined by the bubbles, and the whale then lunges through this circle to the surface. The prey cannot escape, and the whale gets a mouthful.
In these two photos you can see the outline of the bubble-ring on the surface of the water, and how the whale surfaces with a bulging mouthful of water and prey.
Just after departing Detaille Island, we came upon two Humpback whales who were bubble netting. It was like being inside a nature documentary! Well, with the exception of an under-water point-of-view (which would have been chilly). From the bow of the ship we had a good vantage point to see the whales dive, the circle of bubbles rise, and the whales surface within the ring. While aerial photographs of bubble netting give the best perspective, this one was nice for photography because I could include the icy mountains in the background to give context of location. Humpback whales only feed during polar summers, so being able to show that the photo was taken in Antarctica was important.
If you want to know more about bubble-netting behaviour, check out these links:
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