Once used as a common bait fish across the Murray-Darling Basin, the now threatened Southern Pygmy Perch (SPP) has now disappeared from most historically known locations. In NSW there are only three broad locations remaining located nearby the towns of Dalton, Holbrook and Albury. The upper Lachlan drainage near Dalton is the most far-north population houses some of the few persisting SPP populations in Blakney Creek, Urumwalla Creek and Oolong Creek.
Appropriate habitat locations are an important part of native fish recovery, allowing existing populations to thrive naturally, however the suitability of many wild sites is often compromised due to introduced species, habitat degradation, and human intervention.
We know that protecting existing populations, and their habitat, is much more cost effective and successful than reintroduction, however, both are required to support the long-term sustainability of our native fish populations. The approach taken by many recovery efforts now include the use of ‘surrogate’ sites. These sites, sometimes called refuge sites, mimic ideal habitat for fish and are predator free, acting as natural hatcheries, providing a haven for offspring. Farm dams are ideal surrogate sites as they can offer shelter from predators and livestock, and are easy for scientists and researchers to monitor, improving future recovery efforts.
The fish bred at refuge sites such as these, can be used to supplement wild populations through translocation, bolstering genetic diversity and re-establishing populations in historically known locations. A successful example is the translocation of an SPP population that is now well established in Pudman Creek, a tributary of the Boorowa River.
When considering habitat for SPP, current knowledge suggests that we must maintain/provide:
- Instream habitats with appropriate aquatic vegetation
- Seasonal flow regimes
- Intact riparian zones
- Pool depths
- Minimal sediment inputs (from roads and surrounding land use)
- An absence of Redfin Perch, Carp and Eastern Gambusia
(Lintermans and Pearce, 2017)
Threats
The SPP populations within the upper Lachlan are at risk due to several threats. Localised extinction events are becoming more common, with alien species, drought and fire risking the persistence of isolated populations. The establishment and spread of alien species such as Redfin perch, Carp and Eastern gambusia are directly related to SPP declines. A total of 30.72 km of Blakney Creek was sampled in 2007, 2009 and 2013. In 2007 SPP were located in the upper 25.46 km of stream. 2009 surveying identified a contraction in distribution, restricting them to 15.5 km of stream. By 2013, SPP was only found within the upper 12.5 km of stream. This decline correlates with the increased spread of Redfin throughout the stream, with their presence detected in 5.26 km of stream in 2007 to 21.75 km in 2013. These invasive fish not only prey on the SPP but force the species to compete for habitat and resources.
During the 2019 drought, majority of Urumwalla Creek ran dry, restricting fish movement to refuge pools and leading to false rates of abundance during sampling. During the subsequent 2019-2020 bushfires, ash and other sediment produced washed into the system, damaging habitat and aquatic plants. Furthermore, sediment has the ability to smother fish eggs, harming breeding and lifecycle processes.
Local action and community engagement
The team at Gunning District Landcare (GDL) have been working with locals to protect and restore the iconic SPP within the upper Lachlan catchment. The discovery of SPP in Oolong Creek by some local kids from Dalton in 2015, was the catalyst for GDL to commission the 2017 Local Action Plan. This Plan, conducted by Luke Pearce and Mark Lintermans, acted as a guide for the management of the threatened species with the main recommendations being to:
- Protect known sites,
- Monitor the distribution and abundance,
- Conserve and improve habitat,
- Manage alien fish species,
- Extend the species range in the upper catchment
- And improve community awareness
On the 25th of August 2023, a community workshop at Dalton provided an update on the history and status of SPP in the region. The story of the SPP in the Gunning District is one of community and resilience. Ever since the chance discovery of the small fish in 2002 by Mark Lintermans in the Blakney Creek catchment, the community involvement has been inspiring.
The Southern Pygmy Perch Refuge Dams Project is an ongoing project which seeks to find appropriate sites for housing ‘back-up’ populations of this threatened species. There are currently 10 farm dam sites in this project, most of which are fenced to protect riparian zones (a favourable attribute of habitat for SPP). Currently 2 of the dams are stocked with SPP, leaving 8 sites with great potential for the future. These insurance populations will not only serve the remaining Gunning district populations, but also have potential for national translocation throughout the Murray-Darling Basin.
In the days before the workshop, GDL, Luke Pearce and Mark Lintermans (supported by Ozfish) were able to successfully translocate a few 100 SPP for the Southern Pygmy Perch Refuge Dams Project.
Susan Medway is a local involved in the project who had a number of the SPP collected placed into her farm dam. She is a strong supporter of fencing water sources for habitat and restoration purposes. Her farm dam was fenced with support from GDL as part of the Southern Pygmy Perch Refuge Dams Project, and a few years ago she worked with Rivers of Carbon to fence out her property line along Oolong creek. Now, her restoration work is paying off, allowing her to contribute to the long-term survival of the SPP.
In addition to this already successful recovery project, the community is also contributing to monitoring, habitat restoration and alien species management.
Habitat restoration
GDL have hosted planting days and workshops, improving habitat for SPP and teaching the importance of biodiversity within the community.
Monitoring
In 2021, Sonya Duus, Janet Heffernan, Luke Pearce and Mark Lintermans conducted a survey to observe the distribution of SPP in Oolong Creek. The results of this survey were later published in a report supported by Ozfish.
In addition, a citizen science project has been established for future surveying, engaging locals in bait trapping and sampling methods. The community also hope to establish a Waterwatch group in the area to conduct fish surveys and water quality monitoring across 11 sites within the 3 different catchments.
Alien species management
One of the most successful (and endearing) projects GDL have hosted is the 2019 Redfin Fishing Competition which engaged local families to aid in the removal of Redfin from the system. Another local achievement was the construction of two rock barriers on Urrumwalla Creek to prevent the spread of alien species into upstream SPP habitat.
The plight of the SPP is far from over in the face of a changing climate, however, it is the resourcefulness of small local organisations such as GDL are making such a difference.
Video resource
Dalton locals, Rhian Williams and Kim Morrison were inspired to produce a video called ‘Finding Nanno’ the Champions of Change Film Festival. Check it out below to hear from champion GDL volunteer Janet Heffernan.
I would like to thank Janet Heffernan and Sonya Duus from GDL, Luke Pearce from DPI, Mark Lintermans, and the passionate community groups who are working to secure our native fish for future generations.
Resources
Gunning District Landcare Projects
Featured image: Southern Pygmy Perch.
Photo credit: Luke Pearce
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