VIIRS boat detection (VBD) product-based night time fishing vessels observation in the Arabian Sea and Bay of Bengal Sub-regions

NASA's Suomi National Polar-orbiting Partnership (NPP), Visible Infra-red Imaging Radiometer Suite (VIIRS) data utilized to detect night time lights (NTL) radiances and fishing boat pixels using VIIRS boat detection (VBD) approach. Study attempted for first time in Indian waters to detect night time fishing boats during 2017 along with chlorophyll and sea surface temperature (SST). Night-time fishing observed higher in Arabian Sea (AS) compared to Bay of Bengal (BoB). The reason likely the shallower bathymetry (50-200meters) of AS, broader continental shelf and more biological productivity, compared to BoB's narrow and steep continental slope and less productive water. AS night time fishery observed season-dependent (December-May) with VBD pixels ranging 100-300, wherein BoB distribution is sparse, <30 VBD pixels. In AS, moderate/high chlorophyll (0.2-1.2 mgm(-3)), moderate SST (27-30.5 degrees C) and non-cloudy months observed suitable for night time fishing. In BoB, moderate chlorophyll (0.2-0.45 mgm(-3)) and moderate SST (27-30.5 degrees C) played positive role for night light fishing.