Fig. 2. Changes in gizzard mass after a diet switch from mussels to trout pellets (A) or after a switch from trout pellets to mussels (B). Lines indicate the results of the continuous biphasic regression model fitted through the data. Parameters of the biphasic regression models are given in Table2. B1 represents the reaction of group B to the first diet switch trial; B2 represents the reaction of group B to the second diet switch trial. Values are means ± S.E.M.; group A (N=10), group B (N=9) and group C (N=11).