Warming and hypercapnia (elevated CO2partial pressure) prevailing in the future ocean bothaffect the ionic and acid-base regulation in the marine teleosts. Fish gill is a multifunctionalorgan and plays dominant roles in osmotic/ionic and acid-base regulation because it containsvery important ion transpoters and exchangers, such as Na~+/K~+-ATPase,Na~+/HCO_3~--cotransporter, Na~+/H~+-exchanger and Cl-/HCO3--exchanger. Thus ion/osmoticregulation and pH homeostasis rely in part on the same transport processes....