Variance component analysis from linear mixed-model analysis for G. cuvier δ13C and δ15N for two tissue (muscle and liver) and three tissue (muscle, liver and skin) models.

The between-individual component (BIC) represents the total intercept variance and the within-individual component (WIC) represents the residual variance. Total niche width (TNW) is the sum of the intercept and residual variances for δ13C and δ15N. Total BIC and total WIC are calculated by combining the intercept variances for δ13C and δ15N and then dividing by TNW. Proportion of WIC and BIC that explained TNW is in parentheses.