Pacific herring are an important food for most whales. The fast and agile dolphins and porpoise snap up herring individually. In contrast, the huge, filter feeding baleen whales like fin and humpback whales, swallow herring en masse as they do with other schooling forage fish, krill, and other plankton.

The large humpback whales have a special feeding technique. As “gulpers” they swallow a mouthful of prey when they encounter it, versus “skimmers” who continuously swim with an open mouth. To increase their chances of finding prey, a humpback often partners with one or several other humpback whales. Swimming underneath and around a school of herring, they encircle the herring by releasing a curtain of bubbles (3-30m in diameter and about 15m high). This bubble net frightens the herring into a tight school called a “herring ball” or “bait ball”. The humpbacks position themselves under the “fenced” school and swim up from underneath the ball with an open mouth to scoop the fish. An average-sized humpback whale will eat 2000-2500 kg of plankton, krill and small, schooling fish each day, and can scoop up an entire bait ball in one pass. 

Media Credit: 
Mark Wunsch/Greencoast Media Inc.
Friday, January 24, 2014