Remote sensing techniques applied in longline tuna fishery in western Equatorial Atlantic

Abstract

This study aims to investigate the relationship between one tuna specie caught by the longline fleet along the Northeast Brazil (Thunnus alalunga) and some environmental variables obtained from remote sensors such as the sea surface temperature, chlorophyll-a concentration, sea surface height, and wind intensity and velocity. Data from longline catch between 15/spl deg/S and 15/spl deg/N and 010/spl deg/W and 055/spl deg/W, and Additive Generalized Models showed evidence for nonlinear relation. The catch per unit effort (CPUE) was used as an abundance index. This is defined as the number of fish caught by every 100 hooks in a 1/spl deg/ latitude for 1/spl deg/ longitude square grid and integrated in a month of fishing activity for the period of 1995-2000. The relation between albacore (T. alalunga) CPUE and the sea surface temperature indicates that the largest concentration occurred near Brazilian northeast coast in December.