Impact of environment variables on pelagic fish landings: Special emphasis on Indian oil sardine off Tiruchendur coast, Gulf of Mannar

Results of the present study reported the correlation of various environmental variables such as dissolved oxygen (DO), chlorophyll ‘a’, primary productivity (PP), salinity, sea surface temperature (SST) and meteorological parameters such as air temperature (AT), air pressure (AP), relative humidity (RH), wind pattern, sunshine hours (SSH) and rainfall (RF) during January, 2008 to December, 2010 with that of the sardine fish landing along the Tiruchendur coast in Gulf of Mannar. The landings of the pelagic fishes like sardine, anchovy and Indian mackerel were high during south-west monsoon months extending from July to September in Tiruchendur coast. Sardines, which contribute 18.24% of the total fish catch, were recorded throughout the study period with a minimum occurrence during January and maximum in August. Large sized fishes were caught during October. It was found that, moderate temperature, high chlorophyll ‘a’ concentration and phytoplankton abundance are primary factors that enhance sardine fishery. Weather changes, influences fisheries through the modification of habitat characteristics, affecting the organisms to the extent that the physical, chemical and biological conditions that influence their productivity, development, nourishment and reproduction distribution are altered. Subtle changes in key environmental variables can drastically modify the abundance, distribution, and availability of fish populations