Antarctic krill

Antarctic krill (Euphausia superba) is a species of krill that lives in the Antarctic waters of the Southern Ocean. They are shrimp-like and belong to the invertebrates. 

They live in large groups, called swarms. Sometimes these swarms have a density of 10,000–30,000 individual animals per cubic meter. 

They feed directly on very small phytoplankton, so they can use the energy that the phytoplankton originally got from the sun in order to sustain their life in the open ocean. They grow to a length of 6 cm, weigh up to 2 g, and can live for up to six years. They are a key species in the Antarctic ecosystem and are, in terms of biomass, probably the most successful animal species on the planet (approximately 500 million tonnes).

In aquaria, krill have been observed to eat each other. 

 References 

Further reading
 Hempel, G.: The krill-dominated pelagic system of the Southern Ocean. Envir. Inter. 13, pp. 33 – 36; 1987.
 Hempel, G.: Life in the Antarctic sea ice zone. Polar Record 27(162); pp. 249 – 253; 1991
 Hempel, G.; Sherman, K.: Large marine ecosystems of the world: trends in exploitation, protection, and research. Elsevier, Amsterdam: Large marine ecosystems 12, 423 pp; 2003
Nicol, S. & de la Mare, W. K. Ecosystem management and the Antarctic krill. American Scientist 81 (No. 1), pp. 36–47. Biol 9:129–135; 1993.
 Nicol, S.; Foster, J.: Recent trends in the fishery for Antarctic krill , Aquat. Living Resour. 16, pp. 42 – 45; 2003.
 Sahrhage, D.: Antarctic Krill Fisheries: Potential Resources and Ecological Concerns. In Caddy, J. F. (ed.): Marine Invertebrate Fisheries; their assessment and management; pp. 13 – 33. Wiley, 1989.
Ikeda, T. (1984) The influence of feeding on the metabolic activity of Antarctic krill (Euphausia superba Dana). Polar Biology 3(1)
Clarke, A. (1983) Towards an energy budget for krill: The physiology and biochemistry of Euphausia superba Dana. Polar Biology 2(2)

 Other websites 

 Euphausia superba  from MarineBio.
 "Virtual microscope"  of Antarctic krill for an interactive tour of their morphology and behavior, along with other peer-reviewed information.
 "Krill fights for survival as sea ice melts" from the NASA's "Earth Observatory".
 "Antarctic Wildlife at Risk From Overfishing, Experts Say", from National Geographic News, August 5 2003.
  Diary  of the RRS James Clark Ross, giving a popular introduction to the Antarctic krill.
"Less krill for predators in the Southern Ocean"  from the British Antarctic Survey. See also "Climate row touches blue whales", from the BBC, July 19 2001.
 A time to krill 
 Extensive bibliography.
 Krill Count Project 
 WIKIversity Lecture "Biology of Antarctica" 

Category:Krill