EVALUATION OF PRIMARY PRODUCTION AND FISH BIOMASS ALONG CHENNAI COAST USING FIELD AND EMPIRICAL ALGORITHMS

Maritime environment is subjected to extensive variety of anthropogenic effects related with advancement of the beach front zone, contributions of toxins, and excess utilization of marine assets. Marine based photosynthetic life forms comprise of single celled phytoplankton which incorporates under 1 percent of the worldwide biomass anyway it represents 40 percent of the aggregate worldwide carbon fixation. The centralization of chlorophyll-a (principle phytoplankton pigment) is frequently taken as a record of phytoplankton biomass. The available energy flow from primary production during the food chain sustenance will ultimately limit fishery yields in upper trophic-stage. From the inputs of field measured Chlorophyll a an average primary production rates were computed from five distinct algorithms throughout the study area is 433.37 ± 233.58 g C m2 yr1 for estuarine, 395.58 ± 261.59 g C m2 yr1 around nearshore region and for deeper oceans the productivity is averaged as 216.46 ±163.61 g C m2 yr -1 . Further the estimated primary production is used as an input in quantifying the fish production and standing fish biomass .The average fish production estimated from the primary production estimates of different algorithms is 97.73±67.13kg/ha/yr is indicated with changes in number of species and fish life. The total average fish production and fish biomass calculated from the study for 166680 hectares area is 16,289.50tons/yr and 0.17 tons/km2 . It is understood from the collected secondary data for year 2013-2014 (commissioner of Fisheries, Tamilnadu government) the fish catch (34886.35Tons/yr) exceeds the fish production for the study area which indicates either overexploitation of fisheries resources or the caught fish may be migrated origin from the nearby regions.