Spatial and temporal patterns of demersal fish distribution in the northwest coast of India : a study using Geographic Information System (GIS)

摘要

This study illustrates a Geographic Information System (GIS) developed to analyze and visualize spatio-temporal patterns of demersal fish distribution in the northwest coast of India, extending between 17 deg 45 minand 23 deg 00 min N. Main functionsof this GIS are catch and effort estimation and visualisation of their spatio-temporal variation. Catch per unit effort (CPUE) of threadfin breams (Nemipterus spp.), carangids (Decapterus spp.), lizardfish (Saurida spp.), catfish (Tachysurus spp.) and dhoma (Johnius spp. and Otolithes spp.) were mapped seasonally by pooling data from the year 1997 to 2000. Maps displaying CPUE distribution were produced for three seasons; pre-monsoon, monsoon and post-monsoon. Spatial maps indicated occurrence of thesefive species predominantly in deeper waters of the Gujarat coast. GIS is found to be useful in visualizing spatial and temporal distribution and abundance pattern of these key species.