A method used by whales, such as the Humpback whale to hunt food by rounding up concentrated masses of prey. The hunting members of a pod form a circle 10-100 feet across and about 50 feet under the water. Then the whales blow a wall of bubbles as they swim to the surface in a spiral path. The wall of bubbles makes the trapped fish move to the surface of the water in a giant mass. The whales then eat a large, hearty meal.