Seagrass Diversity and Associated Flora and Fauna in the Coral Reef Ecosystem of the Gulf of Mannar, Southeast Coast of India

摘要

The Seagrass diversity and associated flora and fauna in the coral reef ecosystem of the Gulf of Mannar was assisted with Line Intercept Transects (LIT) with help of SCUBA diving during December - March 2010. There were 13 species of seagrass found, among this Cymodocea serrulata was dominant species and the least was Halophila stipulacea. Percentage of seagrass was 68% among this 51% distributed towards the shoreward side and 17% towards the seaward side. Shoot density was 345.9 shoot/m2 at shoreward side and 230.3 shoot/m2 at in seaward side. Among the species, Cymodocea serrulata has high shoot density at both shoreward side and seaward side. Seagrass biomass was 255.6 gdwt/m2 at shoreward side and 129.1 gdwt/m2 at in seaward side. Among the species, Enhalus acoroides has high biomass with 83.5 gdwt/m2 and H. wrightii and H. becarii has lowest biomass with 3.2 gdwt/m2 at shoreward side. Whereas, in seaward side Enhalus acoroides with 54.1 gdwt/m2 followed by Cymodocea serrulata with 35.1 gdwt/m2 and H. decipiens, H. ovata, H. ovalis and H. decipiens has lowest biomass with 2.4 shoot/m2. Seagrass biomass 384.7 gdwt/m2 among this seagrass biomass was 330.9 gdwt/m2 and epiphytic biomass was 53.8 gdwt/m2. Total epiphytic biomass was 53.8 gdwt/m2 among this 35.4 gdwt/m2 at shoreward side and 18.4 gdwt/m2 at in seaward side. Distribution of seagrass along the islands of Gulf of Mannar varies in a very less proportion. But the spatial variation between the shoreward side and seaward side was very high. The present studies reveal that seagrass distribution, diversity, shoot density and associated flora and fauna were significantly higher in shoreward relative to seaward side. This study of seagrass in the coral reef ecosystem of the Gulf of Mannar would be the base line data to know the changes in seagrass population and associated flora and fauna in future.