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<br />Treatment <br /> <br />Exercise Tanks <br />Four rectangular (1.2 m wide, by 7 m long, by 1 m deep) fiberglass tanks were modified and <br />used as experimental rearing tanks. All contained a center divider and a screened enclosure at one end <br />(fig. I) that allowed water to flow around the tank. Two tanks were equipped with electric trolling <br />motors (23 kg thrust), battery banks, and a charger (fig. 2), which provided the elements to create a <br />flowing environment within the tank. The tanks were set up as pairs; water circulated in the treatment <br />tank, whereas the control tank had no flow. This approach provided two complete systems for treatment <br />and control groups and allowed us to work with two species at the same time. <br />Each tank had a net cover, a thermometer, and aeration stone. Generally, a small volume of fresh <br />water was allowed to flow through to an overflow drain. <br />In February 2006, approximately 600 razorback suckers were transported from Willow BNFH <br />and divided among the four test tanks. Their length averaged 198-mm TL (totallength) (range 127 to <br />245 mm, n = 44). In February 2007, 600 razorback suckers were divided between two tanks (flow and <br />control) and 600 bony tail were divided between the other set of tanks. Razorback suckers averaged 222- <br />mm TL (range 190 to 260 mm, n = 88) and bony tail averaged 196-mm TL (range 150 to 260 mm, n = <br />87). <br /> <br /> <br />Figure 1. A pair of experimental rearing tanks modified with center dividers and caged ends. The right <br />tank had a trolling motor (far end) that produced velocities up to 30 cm/s. Fish were held in the left tank <br />without flow (control). <br /> <br />3 <br />