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Potterwalkagee Creek, Murray River, VIC

Mulcra Island floodplain covers an area of 3,199 ha and is located between the Murray River and the Potterwalkagee creek anabranch.

Potterwalkagee creek flows intermittently and passes through shallow wetlands that provide diverse aquatic habitats, including deep and shallow sections with varied flow velocities and both steep and sloping banks. Mulcra Island is located on the Victorian side of the Murray River and the creek has been described as a vital Victorian waterway for Golden Perch.

Over 350 hours were donated by the OzFish Sunraysia Chapter volunteers to complete the project.

How important is the instream woody habitat?

Instream woody habitat, commonly known as ‘snags’, play an important role for many aquatic species and are essential in any healthy waterway, supporting recreational fisheries and other social and cultural values.

Wetlands and creek systems are one of the most productive environments within the Murray Darling Basin, as they provide essential breeding and foraging habitats for a variety of aquatic species. Knowledge of the extent of instream woody habitats is necessary for effective fish habitat management activities.

Woody habitat is an important element for native fish as they use the fallen trees for a place to stop and rest and as a place to breed, feed and shelter.

Recreational anglers and research managers broadly know the types of habitat that can be found in various areas, but such information is usually patchy and can be inconsistent.

High-resolution habitat maps are needed to make informed decisions about future restoration projects and identify sensitive areas that may need protection. This information is best achieved through extensive on-ground surveys.

In 2020 Sunraysia OzFish volunteers set out to do the heavy lifting and extensively mapped each woody habitat located within Potterwalkagee creek.

The mapping was undertaken both from canoes fitted with Humminbird® Side Imaging® Sonars and physically walking along the dry creek bed.

The Results

The information will be used to identify and prioritise sections of Potterwalkagee Creek that need further restoration.

The results indicated that there is a significantly greater abundance and biomass of woody habitats in the upper sections of Potterwalkagee Creek compared to the mid and lower sections. Sunraysia OzFish recommends that a large-scale habitat restoration project be undertaken within the lower and midsections.

The habitat installed should be native vegetation that is found on Mulcra island (River Red Gum or Black Box) and both physically and hydraulically complex to ensure the project is suitable and achieves outcomes specifically for Golden Perch.