The results of monthly observations on the hydrographic parameters in the Gulf of Mannar and Palk Bay during the period 2002-03 are reported. The meteorological parameters for the period have also been compiled. The area received 1120mm rainfall during the period as against a normal of 760mm. Maximum wind velocity of 16.2km/hr was in June and humidity of 78% in December. A comparison of the parameters of temperature, salinity, pH, dissolved oxygen, primary productivity and biomass of both the ecosystems is presented.