Estimated smooth curves obtained by the GAM applied to landings of Sardinella maderensis in the northern area (first column) and the southern area (second column): bottom set gillnet (BSG, a); surface-set gillnet (SSG, b and c); surface-drift gillnet (SDG, d and e); surrounding gillnet (SG, f) and purse seine (PS, g and h). Dashed lines represent two standard error boundaries around the covariate main effects. Significance codes: ^***0.001; ^**0.01; ^*0.05. The x-axis shows the density of points for each covariate and the y-axis reflects the relative importance of each covariate.