Critical regions: A GIS-based model of marine productivity hotspots

Marine productivity hotspots can be defined as areas of high chlorophyll concentration and low temperature distribution. Here we demonstrate how Geographic Information Systems (GIS) can be used to define areas of high productivity and we use fishery data to verify model results and reveal areas of potential fishery locations. We develop a GIS model based on spatial data integration between monthly satellite imagery of Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll concentration (Chl-a) for Eastern Mediterranean waters. Data are analyzed for the production of climatology and mapping of anomaly distribution in these environmental parameters. The geographic distributions of anomalies are spatially integrated to map areas of combined persistent environmental anomaly of below average SST and above average Chl-a (lowSST/highChl-a) indicating marine productivity hotspots and potential fish feeding aggregation regions. A preliminary comparison of surveyed fisheries production data for small pelagic fish and pelagic cephalopods to lowSST/highChl-a areas is performed for the period from December 1997 to November 2001, revealing potential spatial associations among fishery resources and productivity hotspots in terms of unexploited regions as well as overexploited fishing grounds that could be characterized as candidate marine protected areas.