Contribution of remote sensing to the characterization of oceanic variables and their influences on the distribution of tunas in Ivorian waters from 2013 to 2018

Abstract

In view of the threat posed by overfishing of tuna in Gulf of Guinea, the present study was initiated in order to contribute to the sustainable management of this endangered fish species. This study is based on the analysis of oceanic parameters and their influences on the availability of tunas in Côte d'Ivoire. For this purpose, remote sensing data from MODIS, SMOS and ERA Interim sensors were used to estimate Chlorophyll-a concentration, temperature, sea surface salinity, Upwelling Index and turbulence. In addition, the tuna stock data from the Aquaculture and Fisheries Direction of Côte d'Ivoire. An analysis of the oceanic parameters as a function of the tuna stocks allowed to understand the relationships between these parameters and the availability of tunas in Ivorian waters and offshore. The results show that sea surface temperature and Chlorophyll-a concentration are the most preponderant parameters in the distribution of tunas. Preferred spawning periods for tuna cover from December to June with areas of low turbulence, salinity between (34 and 35 psu) and temperatures above 26°C between latitudes 0° and 3°N.