Highlights
- Enhanced O2 unloading due to RBC β-NHE short-circuiting has previously been shown in three salmonids
- Cobia and mahi-mahi both possess rapidly activated red blood cell β-NHE, which is abolished by propranolol
- A decrease in blood pH by 0.2 units may enhance O2 unloading in cobia by over 60% in cobia
- These data provide further support for the hypothesis that enhanced O2 unloading may be a general trait among teleost