Table 4. AIC results for linear mixed-effects models where mean logit-transformed path straightness is a function of ecoregion, sea surface temperature (SST), logarithm of surface chlorophyll a concentration (chla), logarithm of SST gradient (SSTg), logarithm of surface chla gradient (chlag), and logarithm of bathymetry (bathy).
| Model | p1 | AIC | ΔAIC2 | ω3 |
| null | 4 | 7258.06 | 390.51 | 0 |
| ecoregion | 9 | 6927.63 | 60.08 | 0 |
| ecoregion + SSTa | 10 | 6927.26 | 59.71 | 0 |
| ecoregion × SSTb | 11 | 6921.62 | 54.07 | 0 |
| ecoregion + chla1 | 10 | 6908.31 | 40.76 | 0 |
| ecoregion × chlab | 15 | 6908.97 | 41.42 | 0 |
| ecoregion + SSTga | 10 | 6928.73 | 61.18 | 0 |
| ecoregion × SSTgb | 11 | 6929.90 | 62.35 | 0 |
| ecoregion + chlaga | 10 | 6923.94 | 56.39 | 0 |
| ecoregion × chlagb | 15 | 6922.50 | 54.95 | 0 |
| ecoregion + bathymetrya | 10 | 6871.17 | 3.62 | 0.07 |
| ecoregion × bathymetryb | 11 | 6873.15 | 5.60 | 0.03 |
| ecoregion + SSTa + bathymetrya | 11 | 6871.52 | 3.97 | 0.06 |
| ecoregion × SSTb + bathymetrya * | 12 | 6867.55 | 0.00 | 0.42 |
| ecoregion + chlaa + bathymetrya | 11 | 6871.76 | 4.21 | 0.05 |
| ecoregion × chlab + bathymetrya | 16 | 6868.89 | 1.34 | 0.21 |
| ecoregion + SSTga + bathymetrya | 11 | 6873.13 | 5.58 | 0.03 |
| ecoregion × SSTgb + bathymetrya | 12 | 6874.93 | 7.38 | 0.01 |
| ecoregion + chlaga + bathymetrya | 11 | 6871.61 | 4.06 | 0.05 |
| ecoregion × chlagb + bathymetrya | 16 | 6870.84 | 3.29 | 0.08 |
1
p: number of parameters in the model.
2
ΔAIC: difference in AIC value between best fitting model and other model.
3
ω: Akaike weight.
a
Slopes held constant in regions of interest.
b
Slopes and intercepts allowed to vary in regions of interest.
*Best fitting model.