Kickfeeding is a really interesting bit of Humpback behaviour. Basically the whales whack the surface of the water with their flukes thusly:
This causes a pressure wave which stuns small fish near the surface and the whales then dive under them and swim back up, mouths open to engulf the dazed fish. Its basically the same principle as fishing with dynamite only using whale muscle instead of explosives.
If you blow this picture up to unfeasibly large scale you can just make out the guy on the bluefin tuna fishing boat behind the whale's facial expression which is a sort of awestruck "holy s$@#!!!". The giant bluefin tuna (which may be 3m long themselves) will be targetting the same schools of fish as the whales which is why he's exploring this area. Scenery's not bad either.