There are high hopes for the future of a little fish once common in the Murray, Murrumbidgee and Lachlan river systems.
The endangered Southern Pygmy Perch is the focus of a recovery project spearheaded by the Office of Environment and Heritage.
The Wetland Ecology Recovery Program is targeting specific sites across the Murray and Lower Darling river systems to improve water delivery infrastructure, restore habitat and monitor outcomes.
Senior Environmental Water Manager Paul Childs said the initial aim of the program was to develop a recovery plan for the Southern Pygmy Perch, but had since evolved to a whole-of-ecosystem approach focused on threatened fish species.
“Our work to date has focused on several wetlands within the Murray Valley National Park, including Horseshoe Lagoon in the Gulpa Island Precinct,” Mr Childs said. “The OEH has replaced an old structure that deterred the movement of native fish between Horseshoe Lagoon and the Gulpa Creek and replaced it with a box culvert that improves access for native fish and increases the capacity for water flow four-fold.”
“We have also dropped the sill to allow water to enter the lagoon when flows in the creek reach 400 mega litres per day.”
“A monitoring program has been established and while no Southern Pygmy Perch have been detected in the area at this stage we are hopeful that improving their habitat will encourage any remaining Southern Pygmy Perch to return over time.”
Despite improved watering regimes, monitoring of the site has revealed the absence of several key plant species that provide essential habitat for threatened species such as the Southern Pygmy Perch.
“The drought is the likely reason that a number of plant species that we would have expected to find in this wetland environment have not responded to flooding over the past three years,” Mr Childs said. “As a result, we are looking at a seed bank survey to determine the presence and viability of plant species in the soil surrounding the site.”
“The results of that survey may lead to the reintroduction of appropriate plants from other sites in order to restore a more suitable habitat.”
The OEH, together with the NSW Department of Primary Industries and Murray Local Lands Service, are looking at a number of sites across the region as part of the recovery program. These include:
- Norman’s Lagoon near Albury – one of the last sites where Southern Pygmy Perch and Flat-headed galaxias have been recorded in the NSW regulated Murray. The site has historically contained a large diversity of water plants which provide habitat for many wetland species; however like many wetlands along the river most of these plants are now absent. It is the only site within inland NSW where Watershield Brasenia schreberi has been recorded, but is unfortunately now absent. It is also a Sloane’s froglet site. The site, like most, suffered badly during the drought, during which it also suffered a black-water event.
- Sites between Howlong and Corowa where water delivery infrastructure has been installed to help manage flows and implement partial drying, which is essential for allowing soils to stabilise, and optimising water quality outcomes and vegetation recovery. These are also sites where there have been the only recent records in NSW of the critically endangered Flat-headed galaxias.
- Murray Valley National Park – OEH funded a Southern Pygmy Perch ‘presence-absence’ survey that was undertaken in 2013 by Dr Clayton Sharpe in several wetlands and waterways within MVNP.
- Thegoa Lagoon at Wentworth – identified as a suitable habitat for Southern Pygmy Perch and the nationally threatened Southern Bell Frog. It is well known that carp are a major factor in the degradation of wetlands and a key threat to several threatened species. In 2013 OEH funded a carp screen that was installed at the inlet structure to the lagoon from Lock 10. OEH also funded the removal of five tonnes of large carp from a residual pool within Thegoa Lagoon. Unfortunately all carp could not be removed, so the Murray Lower Darling Environmental Water Advisory Group recommended complete drying of the site before the next delivery of environmental water.
The DPI’s Regional Assessment Officer Luke Pearce said work to improve Southern Pygmy Perch habitat was the first step toward restoring the population.
“If the numbers are there, these works should help to bring them back,” he said. “If the numbers aren’t there, we may decide to re-populate or re-introduce the fish from another area.”
“But getting the habitat right is the first step. Southern Pygmy Perch require a habitat where aquatic plants are abundant. The plants provide shelter and a food source for the fish – both plant and other macro-invertebrates.”
The Wetland Ecology Recovery Program has the potential to create flow-on effects for other threatened species in the area including Sloane’s froglet, Southern Bell Frog and Flat-headed galaxias.
The OEH has invested about $80,000 in works and monitoring for the project.
Southern Pygmy Perch profile:
The Southern Pygmy Perch is a small, carnivorous, native fish that was once abundant in the Lachlan, Murrumbidgee and Murray river systems.
It measures between 60 and 70 mm in length with a rounded tail.
The body is generally cream in colour with irregular markings great variation in colour between individuals depending on their local habitat and conditions.
The Southern Pygmy Perch prefers slow moving or still waters.