Movement of three non‐salmonid fish species through a low‐gradient vertical‐slot fishway

Well-designed fishways have assisted in restoring migrations and rehabilitating riverine fish species in all continents. The performance of fishways varies greatly with their type, design and operating regime, and with the species involved. Vertical-slot fishways are widely used to overcome low-level barriers, especially for non-salmonids. Important issues remain in the design of fishways to meet performance and cost criteria, including the relationship between fishway bed gradient and the fish that ascend, and whether resting pools are needed. Models of species' movement patterns can inform fishway designers about likely fish response to various design options, and can lead to improved efficiency and effectiveness. Models of general movement patterns of three potamodromous non-salmonid fishes in the Murray River, Australia, were developed from empirical data in a low-gradient vertical-slot fishway. The models integrate data on times of entry and exit, ascent rates, and whether fish continued to ascend during the night. These fish species did not favour resting pools. Ascent rates of fish ≥120 mm were more closely related to fish behaviour than to length; for a given fishway height, reducing bed slope by increasing the number of pools may slow the ascent of such fish, whereas enlarging pool volumes increases costs. Copyright © 2010 John Wiley & Sons, Ltd.