Many animals in the Southern Ocean ecosystem depend on krill.

Pose the question: Why are krill considered a key species in the Southern Ocean ecosystem?
The survival of conspicuous groups such as whales, seals, penguins, oceanic birds, squid and fish depend directly or indirectly on krill. Discuss how krill's swarming behaviour, its prolific seasonal production and its high protein content make krill such a valuable food source.
How would you find out which animals feed on krill?

• Have students discuss/debate the value of krill as a human food source.What are the significant problems (technological, ecological, economic and social) of krill catching, processing and selling? Discuss possible solutions to these.
• All commercial fisheries on the planet are close to (or are) overfishing their resources. What special precautions would you take to ensure you weren't damaging the ecosystem by overfishing krill?
• What lessons can we learn from the past when other living resources of the Southern Ocean, such as seals and whales, were exploited?
  
  See the articles on the Australian Antarctic Division's website, A time to krill and Krill: magicians of the Southern Ocean.