Fig. 6. Body mass of individually marked fish at weekly intervals over 71 days in the three experimental treatment groups of Series 2: nominal [T_Amm]=0 µmol l^–1 (control, N=64), 70 µmol l^–1 (low ammonia, N=64), and 225 µmol l^–1 (high ammonia, N=48). Values are means ±1 S.E.M. (A) Satiation-fed fish, (B) rationed fish. Within A, asterisks indicate mean body mass significantly higher than the corresponding control mean, and crosses indicate mean body mass significantly lower than the corresponding control mean. ANCOVA indicated significantly higher overall growth over 71 days in the high ammonia treatment, and no significant difference in overall growth over 71 days in the low ammonia treatment relative to controls. Within B, there were no significant differences.