Fig. 1.

Diverse strategies for adaptation of fishes to a hypertonic seawater environment. The ion concentrations are in mM, and osmolality (Osm) is in mOsm/l. The values for eels are for eels acclimated to seawater. The values for seawater are shown in Table 1. All marine mammals, birds and reptiles are iono- and osmoregulators, while the only amphibian that can acclimate to seawater, the crab-eating frog (Fejervarya cancrivora), is an ionoregulator and osmoconformer, as are elasmobranchs. Illustrated by Mari Kawaguchi of Sophia University (https://www.ginganet.org/mari)