Implementing a Spatial Model to Derive Potential Fishing Zones in the Northern Bay of Bengal Lying Adjacent to West Beng
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RESEARCH ARTICLE
Implementing a Spatial Model to Derive Potential Fishing Zones in the Northern Bay of Bengal Lying Adjacent to West Bengal Coast, India Sandip Giri 1 & Sudip Manna 1 & Abhra Chanda 1 & Avirup Chowdhury 1 & Anirban Mukhopadhyay 1 & Sarbari Chakraborty 1 & Sugata Hazra 1
Received: 18 October 2014 / Accepted: 19 June 2015 # Indian Society of Remote Sensing 2015
Abstract 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.
* Sandip Giri [email protected] 1
School of Oceanographic Studies, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
Keywords PFZ . Chlorophyll . SST . Spatial modeling . CPUE
Introduction Oceans are one of the richest natural resources globally and have been fished through history, both for economic reasons as well as human sustenance (Chandran et al. 2004). The marine ecosystems are not static by nature and are affected by many factors, which in turn affect the distribution of fish in ocean waters. It is a known fact that food web dynamics plays a crucial role in influencing fish population in the marine ecosystem. Phytoplankton is at the base of the marine food chain and is known to play a very important role as a marine primary producer. High chlorophyll concentration in the marine water indicates the high primary productivity that in turn regulates the growth and sustenance of the successive higher trophic level organisms like zooplankton and small fishes. The phytoplankton community also supports benthic organisms in aquatic systems. Often a strong phytoplankton community is found necessary for the survival and gro
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