A compendium of ecological knowledge for restoration of freshwater fishes in Australia’s Murray–Darling Basin

Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contemporary ecological knowledge to guide management. This compendium contains knowledge collated from over 600 publications and 27 expert workshops to support the restoration of 9 priority native freshwater fish species, representative of the range of life-history strategies and values in south-eastern Australia’s Murray–Darling Basin. To help prioritise future research investment and restoration actions, ecological knowledge and threats were assessed for each species and life stage. There is considerable new knowledge (80% of publications used were from the past 20 years), but this varied among species and life stages, with most known about adults, then egg, juvenile and larval stages (in that order). The biggest knowledge gaps concerned early life stage requirements, survival, recruitment, growth rates, condition and movements. Key threats include reduced longitudinal and lateral connectivity, altered flows, loss of refugia, reductions in both flowing (lotic) and slackwater riverine habitats, degradation of wetland habitats, alien species interactions and loss of aquatic vegetation. Examples and case studies illustrating the application of this knowledge to underpin effective restoration management are provided. This extensive ecological evidence base for multiple species is presented in a tabular format to assist a range of readers

Natural flow events influence the behaviour and movement patterns of eel-tailed catfish (Tandanus tandanus) in a subtropical Queensland river

Understanding the movement ecology of freshwater fishes, and how these patterns are affected by flow, is important for identifying key threats to populations and predicting their response to management strategies. We used acoustic telemetry to investigate the day-to-day behaviour and movement patterns of eel-tailed catfish (Tandanus tandanus) and examine how their behaviour was affected by natural changes to the flow regime in a subtropical river. Movement patterns varied within the tagged population: 29% were sedentary, 64% undertook interpool movements and 7% undertook reach-scale movements. The mean maximum distance travelled was 0.75 km (±0.33, s.e.) and the maximum distance travelled was 16.9 km downstream. Fish moved upstream and downstream between pools mostly at dawn and dusk, presumably to feed in riffles. Most interpool movements were undertaken during low-flow conditions (<0.2 m s–1 and <6.0 m3 s–1). Generally, the population responded inconsistently to flow events; however, the greatest movement response was detected during the first post-winter flow. Although fish preferred to move on an event fall, several fish continued to move throughout the study reach under baseflow conditions. Management strategies protecting low-flow conditions that maintain connectivity between daytime refuges and riffles may be important for the species' conservation. The effective delivery of post-winter flow events, particularly in perennial systems, is likely to provide critical dispersal opportunities and aid long-term population viability