In order to study the role of the kidney in fish osmoregulation, freshwater acclimatized juvenile spotted
scat (Scatophagus argus L.) were subjected to four different salinities and observed for histomorphometric
changes of the kidney at 1, 2, 10 and 15 days post transfer time points. The overall morphological changes
displayed by fish kidney included significant decrease in the density of collecting tubules and glomeruli
when subjected to higher salinity levels (10, 20 or 30 g/l) in comparison to proliferated, extensive, dense and muscular ones retained in the kidney of residents in freshwater and also of 5 g/l adapted animals. In
conclusion, the observed histomorphological changes in the current study agree well with previously
established physiological differences in the function of teleost kidney in freshwater and in the seawater.