Habitat use by two Atyid Shrimps Caridina Sakishimensis and Caridina typus in Urabaru stream, Kikai-jima Island

Abstract

Habitat use of two atyid shrimps Caridina sakishimensis and Caridina typus was studied along the continuum of Urabaru stream, Kikai-jima Island from May 2007 to April 2008. Occurrence of shrimps was studied at six different microhabitats those were (1) Rocky shelf; (2) Stooping plants; (3) Walls; (4) Green algae (5) Pebble sand and stone (PSS); (6) Bared ground, all these stations were established along river continuum .C. typus occurred at all six microhabitat types; however most preferred habitat by this species was plants. C. sakishimensis and was mainly found at rocky shelf only, it was found with low abundance at other stations. Habitat preference among different life cycles of both species was also studied. All stages of C. typus were found co-existing at plants, On the contrary C. sakishimensis mature individuals and ovigerous females were found associated with Rocky shelf and juveniles were found with plants only. This study revealed that both co-existing species have preferences for different microhabitat, and there is no any competition for space between both of these species.