Southern pygmy perch (Nannoperca australis) is a threatened small-bodied (up to 85 mm length) fish endemic to South-eastern Australia. After the Millennium drought, only four naturally occurring populations remained in Victoria. The fish is short-lived (three to five years) and inhabits still or slow-flowing waters in streams, lakes and wetlands. Spawning occurs from September to January, with rising water temperatures and flow pulses acting as cues.
Unfortunately, this little fish faces many threats:
- a lack of seasonal flooding and modification of natural flows that reduce their ability to recolonise new habitats.
- habitat degradation and loss from farming, urbanisation and wetland drainage.
- livestock access to waterways reducing water quality.
- being preyed upon by introduced fish species including Redfin, trout and Eastern gambusia.
‘Fish in Supplementary Habitats’ (FISH) Program + Landholders to the rescue
The ‘Fish in Supplementary Habitats (FISH) program, funded by the Victorian government, was established in 2018 to conserve threatened Southern pygmy perch and reduce it’s risk from extinction. The program is primarily establishing refuge populations to reduce the potential and immediate threat from catastrophic state-wide loss, and provide source populations for further translocations in the future. It is focusing on:
- identifying private dams with suitable habitats in north-eastern Victoria.
- collecting some fish from existing populations and translocating them to these sites.
- using these refuge populations for future translocations into areas of suitable habitat within their former range.
In early 2018 staff from the Arthur Rylah Institute team undertook site surveys of proposed new homes for the Southern pygmy perch in creeks, dams and wetlands.
486 adult Southern pygmy perch were collected from remnant ‘wild’ populations across Castle, Hughes and Seven Creeks, and from a private property at Edi in northern Victoria.
Four farm dams were chosen as translocation sites and in each of these pre-translocation fish surveys were undertaken to see what was in them before we moved the fish in. In one of these surveys a threatened Galaxias rostratus was found.
In May 2018, 60 adult southern pygmy perch were translocated into two wetlands at Tahbilk, and one wetland at Mitchellstown.
There are still a few more years of this project to run and the researchers involved are hopeful about getting more funding to continue to find new homes for the Southern pygmy perch. If you would like to know more about this project and get in touch with the people involved, please download the fact sheet.
All photos are courtesy of the author Scott Raymond