Fig. 2. Mean food intake (mg food g^-1 body mass) of rainbow trout before and after exposure to 0 (N=10), 500 (N=10), 750 (N=10) or 1000 (N=10-12) µmol l^-1 NH₄Cl for either 24 (A) or 96 (B) h periods. Values are means + 1 S.E.M. Treatments that do not share a common letter for a given feeding time and exposure period are significantly different from each other. ^*Significant differences between the pre- and post-NH₄Cl exposure values for a given treatment; significant differences between the 24 and 96 h post-NH₄Cl exposure values for a given treatment (P<0.05).