shrimp, probably Chorismus antarcticus

Chorismus antarcticus is found throughout Antarctica and South Georgia Island, South Shetland Islands, Marion and Prince Edward Islands, and Chile from 9 to 1,450 meters depth [3,4,5,8,9]. C. antarcticus can be up to ten centimeters long with the rostrum as long as the carapace [5]. Carapace length of C. antarcticus can be over two centimeters (from eyestalk base to central dorsal carapace edge) [1]. C. antarcticus reaches a likely age of ten years in the Weddell Sea [1]. C. antarcticus is a hermaphrodite and undergoes a sex transition from male to female during its the fourth year of life [1,2,6]. C. antarcticus adults are carnivorous and feed on moving prey like amphipods [1].

Shrimp have a semitransparent body flattened from side to side with a flexible abdomen and a fan-shaped tail. Shrimp use their appendages for swimming, swimming backward rapidly by flexing their abdomen and tail. Shrimp usually eat phytoplankton and zooplankton; some feed on dead animals.

Predators of Chorismus antarcticus include the fish Trematomus hansoni, Trematomus bernacchii and Trematomus loennbergii, the Weddell seal, and the brittle star Ophiosparte gigas [7,10,11,12]. Due to slow growth, low mortality rate, and low average abundance, C. antarcticus has little potential for commercial fishing; commercial bottom trawling would over- exploit the stock and destroy its sponge community habitat [1].

1: Journal of Experimental Marine Biology and Ecology 174:261-275, 1993; 2: Polar Biology 17(4):384-388, 1997; 3: Proceedings of the NIPR Symposium on Polar Biology 9:179-206, 1996; 4: Instituto Antartico Chileno. Serie Cientifica 4(1):89-94, 1976; 5: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin : P. Parey, 1990; 6: Adaptations within Antarctic Ecosystems, Proceedings of the Third SCAR Symposium on Antarctic Biology. GA Llano, ed. Washington, DC : Smithsonian Institution, 1977. pp.335-342; 7: Journal of Mammalogy 46(1):37-43, 1965; 8: South African Journal of Antarctic Research 21(1):3- 44, 1991; 9: A Survey of the Marine Fauna in Shallow Coastal Waters of the Vestfold Hills and Rauer Islands, Antarctica. MJ Tucker & HR Burton. ANARE Research Notes 55, 1987; 10: Polar Biology 16(5):309-320, 1996; 11: Polar Biology 17(1):62-68, 1997; 12: Polar Biology 27(11):721-728, 2004

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