Seasonal Variability of Sea Surface Temperature and Chlorophyll Concentration and Its Correlation with Pelagic Fish Catch in Senegalese Exclusive Economic Zone (EEZ)

Abstract

Remote sensing data were used in this study to relate the biophysical characteristics of the ocean and their relationship with the coastal pelagic fish catches in the Senegalese Exclusive Economic Zone (EEZ) from 2003 to 2017. Level 3 (4 km) monthly sea surface temperature (SST), chlorophyll (Chl-a) data from the Moderate Resolution Imaging Spectroradiometer Satellite (MODIS-Aqua) and statistics fishing data were used. These biophysical parameters associated to coastal upwelling index and turbulence water index allowed to characterise availability of fish. The monthly average variation of the biophysical parameters shows a close relation between chlorophyll concentration, sea surface temperature and the pelagic species availability. The results showed that satellite variables are directly related, with high chlorophyll-a concentrations and high upwelling intensities corresponding to low ocean surface temperature. The analysis of intra-annual variations shows the identification of two distinct seasons. A cold season from November to May, marked by an intense upwelling, corresponding to a high concentration of chlorophyll and high upwelling intensity with very high landings of coastal pelagic species. A warm season from June to October corresponding to a low concentration of chlorophyll and a decrease in the intensity of upwelling with low landing values. A hot season extending from June to October, corresponds to a low concentration of chlorophyll-a and a decrease in intensity of upwelling with low landing values.