Blood serum osmotic and ionic regulation of wild adults and reared juvenile Persian sturgeon, Acipenser persicus

The osmoregulatory system was studied in wild adult and reared juvenile Persian sturgeon, Acipenser persicus. The mean osmolarity in blood serum of specimens from the Caspian Sea, estuary, the Kouraneski pools and the rearing tanks were ۳۰۵.۳±۱۴.۳, ۳۰۸.۷±۲۵.۸, ۲۶۵.۰±۱۹.۱ and ۲۵۹.۳±۸.۸ mosmol/L, respectively; the mean concentrations of Na+ were ۱۵۱.۲±۶.۳, ۱۵۲.۲±۸.۴, ۱۴۲.۵±۵.۹ and ۱۳۱.۴±۴.۱ meq/L whereas mean concentrations of K+ were ۲.۷±۰.۹, ۳.۶±۰.۹, ۳.۱±۰.۵ and ۲.۶±۰.۵meq/L, respectively. The concentrations for Mg++ ion in fish of the same four origins were ۱.۵±۰.۲; ۱.۵±۰.۳, ۰.۸±۰.۲ and ۰.۷±۰.۲ meq/L, and those of Ca++ were ۲.۳۱±۰.۵۱, ۲.۶۱±۰.۵۱, ۱.۸۵±۰.۵۸ and ۱.۴۶±۰.۴۳, respectively. The Pearson's correlation coefficient and regression equation indicated that Mg++(r =۰.۳۸) and Na+ (r=۰.۴۱) were effective ions for determination of blood serum osmotic pressure in A. persicus in brackish water and freshwater. This study also showed that blood serum osmotic pressure was independent of sex.