Sandip Giri

BLACKSPOTTED CROAKER, Protonibea diacanthus (Lacepède, 1802): A NEW DIMENSION TO THE FISHING PATTERN IN WEST BENGAL, INDIA

Blackspotted Croaker ( Protonibea diacanthus ) is one of the most commer- cially important croakers which migrate along West Bengal coast during winter season. This paper deals with the importance of the species along with its market value and the cause of its popularity in West Bengal. This species is gaining prime importance among the fishermen due to the high market price of its swim bladder. The dried swim bladders are sold in local markets for Rs. 40,000-50,000 per kg. There is a risk factor involved as the fishermen do not get the catch at a time and, moreover, they often lose common pelagic fishes due to the usage of larger mesh nets. In spite of this risk, a shift from pelagic to demersal fishing across the northern Bay of Bengal marks an important emerging trend of winter fishing in this area.

An index for discrimination of mangroves from non-mangroves using LANDSAT 8 OLI imagery

Graphical abstract

Implementing a Spatial Model to Derive Potential Fishing Zones in the Northern Bay of Bengal Lying Adjacent to West Bengal Coast, India

Potential fishing zones (PFZ’s) are those regions where the fishes aggregate due to an abundance of food and they are demarcated by tracing those regions in the ocean, where a sharp sea surface temperature (SST) gradient along with optimal chlorophyll (Chl) concentration co-exists at a given time. In this regard, Indian National Centre for Ocean Information Services (INCOIS) disseminates the daily PFZ forecasts in Bay of Bengal and Arabian Sea to aid the fishermen community. The present study is an endeavor to develop a local spatial model derived Potential Fishing Zone (PFZ) in the northern Bay of Bengal (nBoB) lying adjacent to the West Bengal coast. Satellite derived SST and chlorophyll data obtained for two consecutive winter seasons of 2010–11 and 2011–12 were used to generate line density (LD) raster. Shapefiles of INCOIS predicted PFZs were overlaid on these LD raster to extract the corresponding pixel values. Histogram ranges of the extracted pixels were fixed and same values lying in the LD raster of both SST and chlorophyll other than INCOIS PFZs were detected by a spatial model in ERDAS. The PFZs thus derived were validated against the ground fish catch data and it was observed that good fish catch was seen in the model derived additional PFZs also. The catch per unit effort (CPUE) values was found to be very close to that of the CPUE value of PFZ advisories of INCOIS. However, the CPUE in the non PFZ areas were significantly lower than the former two categories.