Fig. 5. In vitro haemoglobin-oxygen binding curves for cod blood incubated at the fish's acclimation temperature (7°C), or after incubation temperature was increased to 20 or 24°C. Haematocrit was initially set at 20%, and changes in P_O2 were made every 30 min. The lines were fitted to the data for each temperature using a 4-parameter sigmoidal function. Six individuals were used to generate each curve. See Table 2 for statistical analyses of parameters that define Hb-O₂ affinity and binding capacity.