Fig. 1. Changes in the ammonia excretion rate (µmol day^-1 g^-1 fish) of H. signifer during progressive increase in salinity from 0.7 to 20 though an 8-day period. Open bars represent constant 0.7 salinity for 8 days (control). Filled bars represent increasing salinity from 0.7 (day 1) to 5 (day 2) to 10 (day 3) to 15 (day 4) to 20 (day 5), where it remained until day 8. Results represent means + S.E.M. (N=3). ^* Significantly different from 0.7 control condition at P<0.05; ^a,b significantly different from the corresponding day 1 and 2 values, respectively, at P<0.05.