Geometric morphometrics
As revealed from DFA, differences in body morphology between minnow
caught in the lake versus streams were significant (Mahalonobis distanceD = 5.3026, P < 0.001). Further, DFA classified
90.0 % of all lake individuals and 92.3 % of all stream individuals
correctly into the respective group. In general, lake minnows were
characterized by an upward facing snout and body shape was more
streamlined, whereas stream minnows showed a snout that was pointed
down-ward and the body was bulkier (Figure 3a). The first axis of CVA
(CV 1) explained 59.8 % of the variation in the morphospace and along
this axis, separation between minnows caught in lake and stream habitats
occurred (Figure 3b). CV 2, which explained 18.3 % of the variation,
indicated variability in body shape between the minnows caught in the
different streams (Figure 3b). Pairwise comparisons of minnow body shape
between the locations showed significant differences between lake versus
streams, but further also between L1 and L3 in the lake habitat (Table
1). As seen from the ordination of CVA, minnow morphology of individuals
caught in L3 were most similar to stream minnows (Figure 3b).