A compendium of ecological knowledge for restoration of freshwater fishes in Australia

Abstract

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.

What is needed to restore native fishes in Australia’s Murray–Darling Basin?

“…The Basin Plan and the new NFRS, together with threatened species recovery plans, already provide policy and stakeholder agreement for such actions. The information provided in the compendium by Koehn et al (2020) provides a contemporary knowledge base to support restoration. Immediate commitment is needed now from policy makers, management agencies, community and, most importantly, governments, because they are the final arbiters of implementation.…”

“…Restoration requires knowledge, policy and funded actions over appropriate time scales, so planning and actions are urgently needed to allow this long-term recovery process to begin. The compendium of knowledge of freshwater fishes provided in Koehn et al (2020) indicates that our scientific knowledge base is robust, and improving. Although the MDB Plan (Basin Plan; Murray-Darling Basin Authority 2011) provides a much-needed framework for water reform, including the recovery of water for the environment to support native fishes, there are many additional non-water-related threats that affect recovery.…”

“…Although Koehn et al (2020) provide a contemporary scientific knowledgebase for restoration, it is a large publication, with knowledge condensed into tables and conceptual models for only nine representative fish species. Here, the authors have distilled the key restoration messages identified to provide a brief, clear perspective to guide restoration actions for all MDB fishes that can expedite the recovery of their populations.…”

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

“…Australian native species can produce thousands of eggs per spawn (Harris & Rowland 1996; McDowall 1996; Koehn et al . 2020). Pelagically spawned, buoyant or semi‐buoyant life stages (i.e.…”

“…2008; Koehn et al . 2020). However, this ecological susceptibility is compounded by the significant number of diversions and large volumes of flow diverted across all rivers.…”