The aim of the present study was to investigate the effects of low salinities on ammonia
and urea excretion in experiments allowing comparison of six phylogenetically diverse
species. These experiments differ from previous studies by considering excretion of fasted
fish acclimated to a salinity range from hypo-osmotic and approximately isosmotic (9x
salinity). Most of the previous studies of the effect of salinity on excretion of nitrogenous
wastes investigated changes during the first few days after transfer to a new salinity or
compared hypo-osmotic and hyperosmotic salinities. Differences in methods also hinder
comparison of species used in previous studies.