Long term exposure to brackish water (171 m NaCl) affected the capacity of common carp
Cyprinus carpio to deal with hypoxic conditions and the critical oxygen concentrations for
oxygen consumption increased. In addition, regulation of ammonia excretion was lost. The
cytosolic phosphorylation potential (the index of the energy status of a cell in terms of potential
transferable phosphate groups) in the lateral muscle on the other hand remained relatively
unaffected, indicating that oxygen transport to the tissues was not severely compromised. It
appears that exposure to brackish water reduces the capacity of common carp to cope with
hypoxic conditions mainly because of the high energetic cost of hyperventilation under
conditions where energy stores are depleted, and not because of any impeded oxygen transport
mechanisms