Mean (± S.E.) Cath per unit effort (number of fish/Megalitre) across different mesh and velocity treatments.

<p>Mean (± S.E.) Cath per unit effort (number of fish/Megalitre) across different mesh and velocity treatments.</p

Number of fish entrained within the experimental pump system.

<p>Catches are pooled within each velocity and mesh combination. The electrofishing/seine column demonstrates the composition and relative abundance of fish captured at all the experimental site using electrofishing and seine netting.</p

Length frequency plot for fish sampled a) by electrofishing and seine netting at pumping sites, and b) those collected after being entrained by the pump (all treatments pooled).

<p>Length frequency plot for fish sampled a) by electrofishing and seine netting at pumping sites, and b) those collected after being entrained by the pump (all treatments pooled).</p

Length frequency plot showing the size range of fish observed by sonar to make a) contact or b) avoid contact with the experimental screen.

<p>Length frequency plot showing the size range of fish observed by sonar to make a) contact or b) avoid contact with the experimental screen.</p

Screenshot showing acoustic echogram obtained from sonar (a) alongside post-processing modules created in Echoview, including a background reduction and target identification module (b) and fish tracking module (c).

<p>Screen panels can be seen as light coloured bands at the image bottom.</p

Schematic representation of the experimental pumping station showing major components.

<p>The experimental screen was cylindrical and comprised a series of removable panels to adjust approach velocity and mesh size. Fish that were entrained into the system travelled through the intake pipe, through the pump, along the lay-flat discharge pipe and were collected in fyke nets fitted to a settling tank. Fish behaviour in front of the screen face was quantified using DIDSON.</p

Predicted relationship of probability of screen contact with length and rheotaxis of fish (see methods for description of rheotactic behaviour).

<p>Solid lines are at 0.1 m.sec⁻¹ and broken lines are at 0.5 m.sec^−1.</p

Tabular representation of the two Latin square experimental designs showing the order of allocation of mesh treatments within replicate runs for each of two approach velocities.

<p>Tabular representation of the two Latin square experimental designs showing the order of allocation of mesh treatments within replicate runs for each of two approach velocities.</p

Odds Ratios of rheotactic categories compared to random orientation.

*<p>The odds ratio is the increase in the probability of contact when compared to random orientation. For example, fish showing positive rheotaxis at the 0.1 m/s velocity are 14×less likely to make contact (1÷0.07 = 14).</p>†<p>Significant (sig) or non-significant (ns) at the p = 0.05 level.</p

Location of the four study sites on the Namoi River showing the Murray-Darling Basin (grey thatched).

<p>Location of the four study sites on the Namoi River showing the Murray-Darling Basin (grey thatched).</p