Antarctic krill Euphausia superba

Euphausia superba is found around Antarctica between the continent and the Polar Front within the upper 100 meters of depth [1]. E. superba reaches a maximum length of five centimeters [1]. This photo is an adult male in the typical oblique hovering position with its pleopods beating [4]. E. superba is a swarming species and an important food source for baleen whales including minke whales, seals, fish, birds, and cephalopods [1]. E. crystallorophias replaces E. superba in dominance in regions of pack and floating ice and the pelagic shelf community [1]. E. superba spawns during late spring and summer, peaking from early January to mid-February [1]. E. superba lives two years with recent research suggesting seven years [1]. E. superba feeds preferentially on phytoplankton and is a dominant herbivore in the food web [1]. E. superba feeds on planktonic and ice-attached diatoms, dinoflagellates, silicoflagellates, tintinnids, foraminiferans, radiolarians, heliozoans, Calanus/Calanoides copepods, invertebrate eggs, siphonophores, its own species, other zooplankton [1,5].

Euphausiids are small translucent shrimp-like crustaceans commonly known as krill; seven species belonging to two genera Euphausia and Thysanoessa occur in the Southern Ocean [1,2]. The genus name Euphausia refers to the luminescence produced by large light organs (photophores) [2]. An Antarctic midwater trawling fishery based on Euphausia superba catches krill for human and domentic animal consuption [1]. E. crystallorophias is similar to E. superba but has a longer rostrum, larger eyes, a shorter mandibular palp, and is shorter in overall length [3].

1: FAO Species Identification Sheets for Fishery Purposes : Southern Ocean (Fishing Areas 48, 58 and 88) (CCAMLR Convention Area) / W Fischer & JC Hureau, eds. Rome : Food and Agriculture Organization of the United Nations, 1985; 2: A Practical Guide to the Euphausiids of the World. A de C Baker, BP Boden & E Brinton. London : Natural History Museum Publications, 1990; 3: A Guide to the Euphausiacea of the Southern Ocean. JM Kirkwood. ANARE Research Notes 1 (Australian National Antarctic Research Expedition). Kingston, Tasmania, Australia: Australia Dept of Science and Technology, Antarctic Division, 1984; 4: www.ecoscope.com/krill ; 5: Polar Biology 13(6):389-397, 1993

Text ©Peter Brueggeman. Photograph ©Uwe Kils. Photograph may not be used in any form without the express written permission of Uwe Kils.