European Journal of Molecular & Clinical Medicine ISSN 2515-8260 Volume 07, Issue 09, 2020 1651 STUDY OF PHYSICO-CHEMICAL PARAMETERS FROM BURSATELLA LEACHII HABITATED IN PULICAT LAKE, T.N Mahadev Rama Kokane 1 , K. Revathi 2 , K.Sundaravalli 3 , A.Anitha 3 1 Central Institute of Fisheries Nautical and Engineering Training, Royapuram, Chennai, India, Research Scholar of Mohamed Sathak College, Chennai, India 2 Director of Research, Meenakshi Academy of Higher Education and Research, Chennai, India 3 Research Scholars, Central Research Laboratory, Meenakshi Academy of Higher Education and Research, Chennai, India Email: reva63@rediffmail.com ABSTRACT: Pulicat Lake constitutes a unique and interesting fragile ecosystem in Coromandal coastal zone in South East coast of India. Lake serve as a nursery and breeding ground for many species of aquatic flora & fauna and nesting ground for several species of native & migratory birds. Physico-chemical parameters are the important indicators of environmental degradation like Temp. Salinity, pH, Turbidity, DO, BOD, COD, Total Alkalinity, Total Hardness, Ca, Mg, Nitrate, Phosphate, Carbonate and Bicarbonate, which are essential for ecological balancing and supporting growth of many aquatic organisms. The water samples were collected on monthly basis using small outboard engine motor by reaching particular habitat sits/location of Bursatella leachii species were earlier it found, since sudden out break and sudden disappearance of B. leachii has been noticed worldwide. It was made an attempt to co-relate the availability of B. leachii with Physico-chemical parametrs. In the present study it has been observed that the physico-chemical condition requires for the species Bursatella leachii present in the Pulicat lake. Lake is not affected by the sea water as there are sand bars and shoals in the eastern side of the Lake. Keywords: Pulicat Lake, Water Quality Parameters, Bursatella leachii INTRODUCTION The variation in water quality changes were assessed for two sampling sites in Pulicat lake to know the physical and chemical parameters with reference to the fevourability of Bursatella leachii species. Sea hare species Bursatella leachii exhibits boom-and-bust cycles, forming large aggregation and then disappearing. There are hypothesis for the populations of sea hares exhibiting this kind of dynamic. Hypothesis of aggregation is due to hydrological conditions (Clarke 2006). Lowe and Turner (1976) hypothesized that aggregation of juvenile Bursatella leachii is by the hydrological conditions in subtidal habitats. The sea hare Bursatella leachii is a mollusc from Ophisthobranchia order, Sub class Gastropoda Family Aplysiidae. This marine