They are the most important food source for many marine mammals and sea birds including the minke whale and the macaroni penguin.
Size and population
The average krill is about two inches long but they have strength in numbers – there are around 500 million tonnes of Antarctic Krill in the Southern Ocean! However, in some parts of the Southern Ocean krill numbers have dropped due to reduced sea ice cover.
Krill feed on tiny single-celled plants called phytoplankton.
Krill can be found in oceans around the world.
The loss of sea ice means a loss of ice algae – a vital source of food for krill.