Groundbreaking Photo Shows Humpback Whales Creating Bubble-Nets to Trap ᴘʀᴇʏ
It turns out that humpback whales use nets to catch their ᴘʀᴇʏ, too. They’re just made of different material than the ones fishermen use.
New footage of the giant aquatic mammals shows them using a technique called bubble-net feeding in order to catch ᴘʀᴇʏ. To use this technique, whales round up fish or krill inside a circle of bubbles they have blown from their blowholes. As the whales then rise towards the surface, the fish become trapped in the bubble net, within which the huge humpbacks can then feast. The ring of bubbles will then sᴛᴜɴ and ᴄᴏʀʀᴀʟ ᴘʀᴇʏ — typically either krill or fish — and the pod of whales will ᴇᴀᴛ it.
Marine biologist Lars Bejder of the University of Hawai’i at Mānoa and colleagues used drones to ᴄᴀᴘᴛᴜʀᴇ a bird’s-eye view of the whales feeding. This was combined with data collected from the whale’s point-of-view by cameras and sensors stuck to the marine mammals’ bodies with suction cups. Together, the data provides scientists with an unprecedentedly detailed look at this rare and remarkable feeding method.
“The footage is rather groundbreaking,” said Lars Bejder, director of the UH Mānoa Marine Mammal Research Program (MMRP). “We’re observing how these animals are manipulating their ᴘʀᴇʏ and preparing the ᴘʀᴇʏ for ᴄᴀᴘᴛᴜʀᴇ. It is allowing us to gain new insights that we really haven’t been able to do before.”
During the summer feeding period, about 3,000 humpback whales visit Alaska, while up to 10,000 of them are in Hawaii for the winter breeding period. When leaving their foraging grounds and migrating 3,000 miles, the whales stop feeding until their return several months later. Females in Hawaii use large amounts of energy when giving birth, lactating and raising their offspring before migrating back to their foraging grounds.
Researchers now hope the footage will help shed some light on shifts in habitat and changed in food linked to climate change and ᴘʀᴇʏ depletion.