Super-Aggregations of Krill and Humpback Whales observed in the southern ocean

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.

Read more about it here at ScienceDaily and read the original paper in PLoSOne here.

Image from Nat Geo, Photograph by George F. Mobley

One Response to “Super-Aggregations of Krill and Humpback Whales observed in the southern ocean”

  1. Toni says:

    I’ve read that although this is good for whales, it’s bad for other krill-dependent animals such as the penguins and seals since the whales ate most of the krill. It’s also bad that the change in water temperature reduced the number of krill. If I remember correctly, up to 80% of the population was already lost since the 1980s.

    Toni,
    http://www.youtube.com/watch?v=lj-ZnG3NoZY

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