Morphology
Morphological variation was low among the four dietary groups within the
piscivorous ecotype. The first canonical axis for body shape CVA was
significant (P > 0.05), but head shape CVA revealed no
significant canonical axes (P > 0.05) in groupings (Fig. 5
a, b, c). MANOVAs for body and head shape were not significant (P
> 0.05). Linear measurements CVA revealed one significant
canonical axis (P > 0.05). MANOVA permutation tests
confirmed differences in linear measurements among groups (P = 0.047).
Most distinctions were related to linear measurements of heads, with
upper and lower jaws, head depth, and snout-eye lengths differing
between Group 3 and Group 4 (P ≤ 0.05), and head length differing
between Group 1 and 4 (P = 0.03; Fig. 6). Caudal peduncle length and
anal fin length differed marginally between Groups 2 vs 3 (P = 0.068)
and Groups 1 vs 3 (P = 0.075), respectively. The first two PCA axes
explained 44.3% and 12.3 % of variation for body shape, 35.1% and
30.7 % of variation for head shape, and 39.6 % and 20.9 % for linear
measurements (Fig. 5 d, e, f).