Think of marine mammals, which breathe air like we do but drink only salt water; and think of fish such as salmon which live part of their life in saltwater and part in freshwater. How do aquatic organisms deal with the different concentrations of salt in the water? These birds have salt glands behind their eyes that drain excess salt out the tip of the beak. Most fish constantly gulp down water to keep from drying out, but saltwater fish also pump out salt through their kidneys and specialized gills.