Elasmobranchs appear to employ different acid-base
regulatory mechanisms, because responses of plasma sodium and chloride ion concentrations to hypercapnia differ
from those in teleosts. Previous studies on elasmobranchs
reported either no change in plasma Cl
during hypercapnia
for skate [Graham et al., 1990] and larger spotted dogfish
[Randall et al., 1976], or a small but significant decrease for
spiny dogfish,Squalus acanthias[Cross et al., 1969]. We
also found significantly smaller decreases in Cl
, as compared with rises in plasma HCO3
in starspotted dogfish
[Hayashi et al., 2004]