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).