it's been a long swim from warm equatorial waters more than 3,000 miles away, but it's all worth it for the krill. during the summer, billions of these tiny crustaceans swarm these waters to feast on the plankton. for the next few months he'll gorge himself on around four tons a day before returning north. while whales are here for the krill, oceanographer susanna bucking is here for the whales. with 700 migrating to the corcovado gulf every summer, there's nowhere else she would rather be. >> as a child i developed kind