Sea surface temperature (SST) is one of the most important parameters in monitoring ecosystem health in the marine and coastal environment. Coastal ecosystem is largely dependent on ambient temperature and temperature fronts for marine/coastal habitat and its sustainability. Hence, thermal pollution is seen as a severe threat for ecological health of coastal waters across the world. Mumbai is one of the largest metropolises of the world and faces severe domestic and industrial effluent disposal problem, of which thermal pollution is a major issue with policy-makers and environmental stakeholders. This study attempts to understand the long-term SST variation in the coastal waters off Mumbai, on the western coast of India, and to identify thermal pollution zones. Analysis of SST trends in the near-coastal waters for the pre- and post-monsoon seasons from the year 2004 to the year 2010 has been carried out using Moderate Resolution Imaging Spectro-radiometer (MODIS) Thermal Infra-red (TIR) bands. SST is calculated with the help of bands 31 and 32 using split window method. Several statistical operations were then applied to find the seasonal averages in SST and the standard deviation of SST in the study area. Maximum variation in SST was found within a perpendicular distance of 5 km from the shoreline during the study period. Also, a warm water mass was found to form consistently off coast during the winter months. Several anthropogenic sources of thermal pollution could be identified which were found to impact various locations along the coast.

The dense population of the metropolis Mumbai, exerts a lot of stress on the overall ecosystem including coastal zones. Authors have attempted to study the coastal ecosystem health using long term chlorophyll-a and Sea Surface temperature (SST) trends from [2003][2004][2005][2006][2007][2008][2009][2010][2011][2012]. Remotely sensed data has been used for this study because of its proven advantages. MODIS data has been used to estimate the chlorophyll-a and SST trends. Fish catch data is plotted and its correlation using Pearson Correlation technique is used for Chlorophyll and SST data around Mumbai.The study area was divided into zones based on the variations observed during field visits in the ambient water conditions; these zones are 0-15 km, 15-30 km and 0-30 km zones. In the 0-15 km zone, Pearson correlation coefficient for chlorophyll-a with fish catch data was found to be 0.06 whereas for the 15-30 km zone it was found to be comparatively higher at 0.46. But in the 0-30 km zone the correlation coefficient of chlorophyll-a with fish catch was found to be 0.4. SST correlation with fish catch was found to be highest in the 0-15 km range at 0.47.