The pHvalue,water salinity and temperaturewere determined from the average of three readings at each station using the multiparameter instrument (Hanna Instruments,HI 9829).Dissolved
oxygen was determined by Winkler’s method (Strickland and Parsons, 1972) and the nutrient salts (NO3, NO2, NH4, PO4 and SiO4)were determined spectrophotometrically in lMaccording to the methods described by APHA (2005).