Studies on the blood and branchial mucous cells of freshwater and marine alewives (Alosa pseudoharengus)

Abstract

1. 1. Hematocrit values were determined for a freshwater and a marine population of alewives. Hematocrit values were significantly higher in marine specimens. 2. 2. No differences in plasma sodium and plasma potassium levels were observed between the two populations. 3. 3. Lower plasma prolactin levels in the plasma of Lake Michigan fish are probably due to greater usage of the hormone in freshwater. 4. 4. Density of branchial mucous cells was found to be higher in the marine specimens. © 1979.