Partitioning of body fluids in the Lake Nicaragua shark and three marine sharks.

The relative volumes of major body fluids of freshwater and marine sharks are remarkably similar in spite of the differences in external medium and in osmotic pressure of body fluids. The small differences detected are in agreement with differences reported in comparisons of freshwater and marine teleosts: a slightly higher total water content and a smiller ratio of extracellular to intracellular fluids in freshwater forms.