Humpback whales are now arriving in the waters of the Great Bear Rainforest to feast on Pacific herring and other forage fish. When hunting, humpback whales are often seen “bubble-net feeding”, strategically working together together to cooperatively trap fish. Using tactics of tail slapping (known as “lobtail feeding”) and producing loud feeding calls that pierce the water at a frequency of 500 hertz, the whales each have choreographed roles to play during the hunt. Their panic-stricken prey begin to instinctually form tight schools known as “bait balls.” At the same time, the whales release bubbles from their blowholes, forming a curtain of bubbles around their prey that may range from 15 to 100 feet in diameter. On a signal from the leader, the pod lunges to the surface to devour the trapped fish.
The rhythmic feeding call used in these hunts can exceed 180 decibels, loud enough to burst a human eardrum. It was first identified in 1974 and has always been observed in groups…until recently. New research from Alaska has observed whales belting out the feeding call completely solo! This suggests that the call may be more about corralling schools of herring than about coordinating the feeding strategy. Research has shown that humpbacks have the capacity to transfer information among individuals – we wonder if this solo hunting tactic will be adopted in the years to come in the waters off the Pacific Coast and will have our ears glued to Pacific Wild’s Great Bear Sea Hydrophone Network.
Learn more about how we monitor ambient ocean noise and cetaceans here: pacificwild.org/initiatives/ocean/great-bear-sea-hydrophone-network
The audio of the bubble-net feeding in this video was recorded via Pacific Wild’s Great Bear Sea Hydrophone Network off of Ista (King Island). Filmed by Ian McAllister, April Bencze, Andy Maser // Edited by Lindsay Marie Stewart // Music by Tony Anderson: Dreamlife, themusicbed.com