Scientists from Duke – just down the road – have published a neat report of a “super-agregation” of humback whales feeding on a swarm of krill in Wilhelmina Bay, along the coast of Antarctica. The team was working in the area in May 2009 when they stumbled into the massive feeding aggregation, certainly attracted by their favorite food.
They estimated there was approximately 2 million tons of krill spread over a 100 km2 area. The krill densities were up to 2000 individuals per cubic meter, which would have made feeding on them very efficient. The whales rested during the day and fed at night when the krill migrated toward the surface.
The krill aggregation was the largest reported in over 20 years and the highest density of humpback whales ever documented in the region. In one sense, this is good news, i.e., seeing more evidence of humpback whales recovering in the Southern Oceans after they were so overfished. It is also good to see so many krill which are also being heavily fished and are the key food item for other marine mammals and sea birds.