Figure 4:

The mean duration of time each fish spent impinged upon the structure for each modification. The control treatment was not included in this comparison, because fish were unable to become impinged upon the pipe itself (with no modification). Different lowercase letters indicate statistically significant differences among treatments. Black line represents the median, box the interquartile range (IQR), whiskers = 1.5 IQR, filled circles represent outliers, and diamond indicates the mean. Mean proportions of fish diverted for each treatment (±SEM) are reported in the text. n = 6 trials for each treatment, 60 (±3) fish per trial.