Changes in PCO2 do not generally affect the O2
consumption rate of resting fish (carp Cyprinus carpio
[Takeda, 1991]; mummichog Fundulus heteroclitusand
spot fish Leiostomus xanthurus[Cochran and Burnett,
1996]), although a transient increase in O2 consumption
rate was reported upon application of hypercapnia for some
species (larger spotted dogfish Scyliorhinus stellaris
[Randall et al., 1976]; skate Raja ocellata[Graham et al.,
1990]; rainbow trout [Thomas et al., 1983]). Thus even in
the face of reduced oxygen-binding affinity and capacity of
hemoglobin by CO2(Bohr and Root effects), fish appear to
be able to satisfy the oxygen demand of tissues as long as
no exercise is required