The fish won't pass through the bubble curtain, perhaps seeing it the same way it sees the water's surface. Then the whale vocalizes a slightly more monotone version of its famous courting songs. It sings this hunting song so loudly that the sound waves effectively paralyze its prey . The whale rises into the bubble curtain, open its huge mouth and gives entrance to several thousand pounds of salt water and incapacitated fish. It closes its mouth, immediately starts pushing its car-sized tongue up against its baleen mesh.
Salt water is forced out.
The krill or herring are caught up in the mesh. The whale sucks the animals down its throat. Another meal complete. The humpback whales feed this way all summer long in the waterways of southeast Alaska. They are so numerous in parts of Frederick Sound north of Petersburg, that when the day is clear, it sometimes seems that a person would have to stay below decks if, for some crazy reason, he or she wishes to avoid seeing them.