During the feeding frenzy humpbacks dive deep down and blow the bubbles that herd the fishes to a giant ball. Then they just lunge through it mouths wide open and catch it. Sometimes you can see their huge mouths open, sometimes just the tips of their snouts slightly above the surface, like this picture. The remains of the bubble net can be seen on the left side of two humpbacks on the surface.
Photo (c) Miikka Järvinen, from my gallery Humpback whales and seals feeding in Monterey Bay, CA.
