NSW Department of Primary Industries/Murray Local Land Services, $120,000
Dr Lee Baumgartner, Dr Luiz Silva, Dr Stacey Kopf, Daniel Svozil
Macquarie Perch, a threatened species, was once very prevalent along the Murray. However there has been a big reduction in its population with only one small population remaining in Dartmouth Dam, in the Victorian portion of the Murray catchment, and another [possibly] in Mannus Creek, in the NSW portion of the Murray catchment.
The initial aim of this project was to determine whether or not the populations of Macquarie Perch in Mannus Creek (one fish was found in 2009) had persisted following the failure of Mannus Dam in October 2010, and then a major flood event.
Researchers began their first sampling for Macquarie Perch in June 2017 at 15 sites - five sites upstream of Mannus Dam which has been reinstated; five sites immediately below the dam to Mannus Falls; and five sites from the falls to the Tooma bridge – a distance of about 65kms. Coupled with the fish sampling was a habitat mapping assessment undertaken in November 2017 which collected data about all the different structures (pool size and depth, refuge habitat, woody habitat, riparian vegetation, pest plant species, and refuge areas) along the creek’s 65km length. A second round of sampling was undertaken in February 2018.
The sampling found, not only Maquarie perch, but the presence of another eight fish species along the sampling area, including three natives (Murray cod, Mountain galaxias and River blackfish) and five invasive species (Redfin perch, Common carp, Brown trout, Goldfish and Gambusia). Special attention was given to the distribution of Redfin perch in the area as that species preys on all different life stages of Macquarie Perch.
The researchers have analysed the habitat mapping data, correlating the presence/absence of Macquarie perch with habitat features. This has provided a guide for identifying other areas that may have habitat features suitable for Macquarie Perch.
The main findings of the project were:
Final Report: Silva, L., Pearce, L.,Mabon, S., Horta, A., Duffy, D., Kopf, S., Ning, N., Baumgartner, L. (2018) Macca's in the Manus, Macquarie perch refuge in the Upper Murray. ILWS Report 114
The Final report included a long term management plan for the Mannus Creek Macquarie perch population suggesting seven strategies to be implemented:
Dr Luiz Silva has been invited to join the Macquarie perch Working Group established by NSW LLS. The group will discuss strategies and determine priorities for Macquarie perch conservation and recovery following the development of a National Macquarie perch Recovery Plan. The Plan, published in 2018, suggests a series of actions necessary to improve and recover Macquarie perch populations nationally. Its success will be measured within 10 years (http://www.environment.gov.au/system/files/resources/bdee49ef-45da-4eb7-b548-bcfce460a21b/files/recovery-plan-macquarie-perch-2018.pdf);
Dr Luiz Silva