Dietary protein intake is the most important factor affecting ammonia excretion, so
fasted fish were used to better evaluate the influence of other variables. In fish fed to
satiation, ammonia production may be 10-fold greater than in starved fish (Wood, 1993).
Once feeding is terminated, ammonia production declines rapidly, and stable levels are
achieved after 5 days (Fromm, 1963). In the present study, the use of fasted fish resulted in
low rates of excretion of nitrogenous wastes, which were similar to those reported in
previous studies of fasted fish (Lauff and Wood, 1996). Future studies should consider the
effects of salinity on nitrogenous wastes of fish after feeding.