Fig 1.
Plan view of the experimental set-up for minnow (top) and trout (bottom). The experimental area was isolated from the rest of the flume using tubular flow straighteners (upstream and downstream). Dotted lines display the central zone and small black boxes at the sides of the flume the position of the visual cues (vertical stripes). The positions of flow measurements are indicated by small crosses. Flow was from left to right. The scale bar in the bottom left of each box represents the mean fish fork length for that species.
Table 1.
Summary of mean unidirectional flow velocities (± SD) and sample sizes for low, medium and high velocity treatments for common minnow (Phoxinus phoxinus) and brown trout (Salmo trutta).
Table 2.
Definitions of the behavioural metrics devised to statistically analyse fish behaviour during each trial.
Fig 2.
The percentage of time spent in the central zone of a flume with (dark grey) and without visual cues (light grey–the control) under three flow velocities for (a) common minnow and (b) brown trout.
Fig 3.
The Number of visits to the central zone for the control (light grey) and visual cue treatment (dark grey) at the three flow velocities for (a) common minnow and (b) brown trout. Note the difference in y-axis scale.
Fig 4.
Median Duration of visits to the central zone for the control (light grey) and visual cue treatment (dark grey) at the three flow velocities for (a) common minnow and (b) brown trout. Note the difference in y-axis scale—the scale for minnow has been log transformed.