The water wasn't this clear just a week ago; the krill had done an excellent job of cleaning it up. Even with the clear water, tracking the penguins in it was incredibly difficult; their clumsy aloofness on land is exchanged for astonishing nimbleness and speed in the water.
But the whales! They would dive to just under the surface, turn sideways and take an enormous mouthful of the krill they'd driven to the surface. Their mouths would open ten feet wide, giving us sight of what passes for whale teeth; baleen, delicate structures used to filter the krill out from the seawater.
And then they'd dive again, to repeat the process over and over. We followed them at a very respectful distance, mostly drifting with the currents with the engine off. The only sounds we had were humpback whales breathing and singing.