Mangroves are keystone ecosystems which provide numerous environmental services. Mangroves assume significance as standing stores of sequestered atmospheric carbon and are therefore, important in the light of climate change mitigation. In this study, we attempted to assess the biomass of mangroves in the Kadalundi wetland, south-west coast of India and evaluated the potential of these mangroves to sequester and store carbon. The C-stocks of above-ground and root biomass were 83.32±11.06 t C ha-1 and 34.96±4.30 t C ha-1 respectively, while the C-stock in sediment was estimated to be 63.87±8.67 t C ha-1. The estimates of mean combined C-stocks in the mangrove biomass and sediment of Kadalundi shows that this estuarine mangrove wetland stored 182.15 t C ha-1, which was equivalent to 668.48 t CO2 ha-1. The mangroves which cover an area of 13.23 ha in the Kadalundi wetland is assumed to have a potential to sequester and store a substantial quantity of 2,409.84 t C which is equivalent to 8,844.11 t CO2. The study underscores the importance of these intertidal forests for climate change mitigation and stresses the importance of protecting the mangroves which provide many other important ecosystem services that benefit communities.

Gulf of Mannar Ecosystem (GOME) covers an area spread over Rameswaram and Kanyakumari for about 19000 km 2 and lies between 78°11'E and 79°15' E longitude and 8°49'N and 9°15'N latitude. The 21 coral islands form a network of habitats for different kinds of fishes and marine organisms.

The diversity of finfishes caught in traps at Keelakarai, Gulf of Mannar was assessed quantitatively and qualitatively for a period of six years from July 2006 to June 2012. Average landing during the period was 109 t per year with maximum of 137 t during 2008-09. Among the 98 species of reef fishes landed, Siganus canaliculatus dominated (28%), followed by Scarus ghobban (21%). During the first two years of the study, S. ghobban dominated over S. canaliculatus and later the trend reversed. Family-wise, maximum contribution was by Siganidae (36%) followed by Scaridae (21%). Seasonally, the major peak was recorded during post-monsoon of 2009. The Shannon index of diversity was maximum during 2007-08. Cluster analysis indicated the highest similarity in species composition between 2010-11 and 2011-12. SIMPER analysis identified 26 species as most significant in creating the observed pattern of similarity for 90% cut off contributions. Ellipse plot showed statistically significant deviation in fish diversity between years. Reef fish landings showed an increasing trend from 2006-07 to 2008-09, a decline afterwards and then almost steady condition prevailed during the last two years of the study which implies that there is no scope for further increase in landings by trap fishery at Keelakarai.

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