Approach velocity and impingement duration influences the mortality of juvenile Golden Perch (Macquaria ambigua) at a fish exclusion screen

Abstract

Summary Globally, the extraction and diversion of water from river systems has had substantial impacts on aquatic ecosystem health and ecological processes. One such impact is the entrainment of fish at pump offtakes that can result in vast quantities of fish being permanently removed from rivers. Exclusion screens to prevent fish entrainment at pump offtakes are therefore an important management consideration. In this study, impingement and subsequent injury and mortality of a juvenile freshwater perciform, Golden Perch (Macquaria ambigua), was assessed in the laboratory using a simulated fish exclusion screen under a range of velocities and impingement durations. A 2 mm wedge‐wire screen eliminated the entrainment of 44‐day‐old Golden Perch that were exposed to approach velocities between 0.05 and 0.3 m/s. However, impingement rates of Golden Perch increased significantly with increased approach velocities and rates of injury and mortality increased with impingement duration. Results from this study indicate the primary mechanisms to reduce fish loss at pump offtakes are to design pump offtakes, fitted with fish exclusion screens, which limit approach velocities or impingement duration. Further studies are required to examine a range of species with varying swimming ability at early life‐history stages. Such data will contribute to the growing body of knowledge that supports adaptive management plans to prevent fish loss at water offtake pumps.

Design, construction, and preliminary hydraulic evaluation of a model rock ramp fishway

“…There are other fish passage research flumes in existence, including the large flumes at the U.S. Geological Survey Leetown Science Center's Conte Anadromous Fish Center (Castro‐Santos et al 1996; Haro et al 2004) and those at the U.S. Fish and Wildlife Service Bozeman Fish Technology Center (Dockery et al 2017; Plymesser et al 2022) in the United States, as well as similar facilities in Europe (see Romão et al 2018), Asia, South America, and Australia (Boys et al 2013; Stocks et al 2018). Each research center and the associated flumes have unique capabilities based on the original design purposes and their ability to hold or import fish of different species.…”

Native fish losses due to water extraction in Australian rivers: Evidence, impacts and a solution in modern fish‐ and farm‐friendly screens

“…2013b; Stocks et al . 2018) and further studies on fish eggs and larval fish are nearing completion. They show that internationally accepted approach velocities of 0.1 m/s will successfully reduce losses of Australian native species by over 90%.…”

“…Fortunately, this process of testing and adaptation is already well-advanced in Australia so that screens can be installed with a high degree of confidence. Laboratory and field studies focusing on young-ofyear and older fish have now been completed (Boys et al 2012;Boys et al 2013a;Boys et al 2013b;Stocks et al 2018) and further studies on fish eggs and larval fish are nearing completion. They show that internationally accepted approach velocities of 0.1 m/s will successfully reduce losses of Australian native species by over 90%.…”

Alleviating the loss: A conical fish screen installation reduces native fish entrainment at a gravity‐fed water diversion

“…In recent years, there has been a large effort to tailor the design of fish screens to protect Australian native species and ensure they can be effective in the slow‐flowing water conditions often found in semi‐arid river systems (Baumgartner & Boys, 2012; Boys, 2021). Screen testing, including the entrainment or impingement of Australian fishes, has been conducted on juvenile native species, such as silver perch ( Bidyanus bidyanus ) and golden perch ( M. ambigua ) under controlled laboratory conditions but has yet to be tested in the field (Boys, Baumgartner & Lowry, 2013; Stocks et al, 2019). There is a lack of knowledge about how fish screen technology adapted from the northern hemisphere performs under Australian conditions when evaluating the ecological benefits.…”

“…Screen testing, including the entrainment or impingement of Australian fishes, has been conducted on juvenile native species, such as silver perch (Bidyanus bidyanus) and golden perch (M. ambigua) under controlled laboratory conditions but has yet to be tested in the field (Boys, Baumgartner & Lowry, 2013;Stocks et al, 2019). There is a lack of knowledge about how fish screen technology adapted from the northern hemisphere performs under Australian conditions when evaluating the ecological benefits.…”