Analysis of simultaneous sonor scans from a surface vessel and film from a remotely operated underwater camera show that euphausiids form extremely dense micropatches upon which humpback whales feed. Krill densities were found to be several orders of magnitude greater than values previously reported from results of towed net samplings and were sufficiently dense to allow capture of the whales calculated minimum daily caloric requirements in a matter of several dives. Dive depth during foraging episodes can be predicted with a high degree of confidence from ventilatory, surfacing, and diving patterns of a whale.