Statistical analyses
To analyze the variation in TDF between weight classes, we conducted
four different ANCOVAs with subsequent Bonferroni posthoc comparisons
using Δ13C and
Δ15N, for the two tissue types muscle and
liver. We used final weight as a covariate with the attempt to adjust
for the variation explained solely by growth (Fry and Arnold 1982).
Additionally, we conducted four linear regressions with the
Δ13C and Δ15N, for muscle
and liver tissue respectively as dependent variables and SMR as the
predictor in order to analyze the relationship between TDF and SMR. We
compared SMR between the different weight classes using an ANCOVA with
subsequent Bonferroni posthoc comparisons, including final weight as a
covariate. The assumptions of normal distribution and homogeneities of
variances were met for all parametric analyses. We used IBM SPSS
(version 25) for statistical analyses.