OBSERVATIONS ON OSMOREGULATION IN THE ARCTIC CHAR (SALVELINUS ALPINUS L.)

Abstract

Adult Arctic char, taken in summer from Hebron Fjord, Labrador, and Hudson Bay near Churchill, Manitoba, were transferred directly from salt to fresh water under fairly constant conditions. Decreases in blood freezing point and chloride concentration of the order of 25% were found, the char thus being like most other anadromous salmonids in this respect. Possibility of improved regulation of muscle concentrations is indicated. Data are presented on plasma freezing point, Cl, and K, muscle solids, Cl, and K. Physiological differences between populations of char are indicated.