Monthly variations of physico-chemical characteristics were carried out in Poompuhar marine water samples, South east coast of Tamil Nadu, India, for a period of twelve months (January 2015 to December 2015). Eight various physico-chemical parameters were analyzed by using standard methods (APHA, 1998). Water temperature varied from 22.75 to 35.25°C, turbidity was from 43.75 to 71.12 cm, pH ranged from 7.2 to 8.67, salinity (21.27 to 34.5 ppt), dissolved oxygen content varied between 3.49 to 5.33 mg/L, calcium (123.25 to 252.5 mg/L), nitrate (0.52 to 0.86 mg/L) and ammonia (0.12 to 0.33 mg/L) also varied independently. The maximum and minimum were noted during the study period January 2015 to December 2015.
