Salinity tolerances of three species of freshwater atyid shrimps ( Decapoda : Caridea) of Sri Lanka

Abstract

Salinity tolerances of Caridina femandoi, Ca+idina pristis and Cadinu simoni were studied in the laboratory by subjecting individuals from three popula- tions 'of each bpecies to a graded series of concentrations of sea water. C. pristis showed the lowest salinity tolerance and C. simoai showed the highest salinity tolerance. The ultimate incipient lethal salinities (which just fail to kill 50% of the sample on indefinite exposure) of C. pristis, C. femandoi and C. simani appear to be about 10.5, 13.5 and 16.5 ppt NaCl respectively. The possible influence of the salinity tolerance on the geographic distribution of the three species is discussed.