Fig. 5. Enzyme activities for glutamine synthetase (GSase), ornithine transcarbamylase (OTCase), arginase and carbamoyl phosphate synthetase III (CPSase III) measured in homogenized whole toadfish. Developmental stages presented are egg II (10–20 days post-fertilization), yolk-sac larvae I (1–7 days post-hatch), yolk-sac larvae II (8–14 days post-hatch) and juveniles (yolk-sac completely absorbed; <16 mm TL). Various developmental stages were collected in Biscayne Bay and flash frozen with liquid N₂. Statistically different groupings (a–d) from one-way ANOVA post-hoc analysis are presented above bars for each ornithine–urea cycle enzyme group. Values are means + S.E.M., =0.05 and N=6 for each developmental stage. Note that CPSase III activity is expressed as nmol min^–1 g^–1 (y₂ axis).