Western Murray Land Improvement Group, The Koondrook and Barham Bridge Newspaper

Community Koondrook-Perricoota Forest Vision Statement:

“A healthy working forest where native species can flourish, and where local communities can connect and co-manage the forest for future generations.”

Last month, we published an article describing the outstanding vegetation response seen across the KP Forest following successive wet years. But what about the fish, and what is happening as this hot, dry summer progresses, and the forest dries out?

To recap, monitoring fish, bird and vegetation environmental outcomes are vital to show change over time/validate the outcomes of environmental water use at the Living Murray icon sites. The Koondrook- Perricoota-Gunbower Forests is one of the sites, and Forestry Corporation of NSW is the land and icon site manager of Koondrook-Perricoota (KP) Forest.

Over the past few months, various locations within the KP Forest have been sampled for native and exotic fish abundance and biomass, as part of the annual monitoring program. This sampling has involved a combination of fyke netting, and electrofishing either by boat or backpack. Neither the netting nor electrofishing methods result in any harm to native species.

Monitoring was undertaken by Environmental Consultants, Dan Hutton and Dr John Conallin, in conjunction with members of the Moama and Deniliquin Local Aboriginal Land Councils, Barapa Barapa and Yorta Yorta Nations.

Fyke nets are a type of fish trap, shaped like a cylinder, with a series of openings which funnel fish into the net. Electrofishing involves an electric current temporarily stunning fish for capture, whereby they are identified, counted and measured, and in the case of native species, quickly released back into the water. 35 locations within the KP Forest are monitored annually, with sampling completed in over 90 per cent of sites in 2025 at time of print.

All the fyke netting sites have been completed, and the results of these locations indicate an incredible reversal of the ratio of native to exotic fish species since the 2022 floods. In 2022, native species comprised 20 per cent of the catch, and exotics 80 per cent. This year, native species comprised 85 per cent – refer to the graph on the right.

As Dan Hutton explains, analysis of the biomass (weight) of the catch paints a different picture; native species comprise 17 per cent of the catch by weight. However, this is a considerable increase since 2022, when natives comprised 3 per cent of the catch by weight. This year, the high exotic biomass is attributable to burgeoning carp.

The native species netted were small-bodied species. Dan also identified very few small carp were caught, which indicates waterbirds have been successful in keeping their numbers down. Some of the native fish caught include Australian smelt, two types of Gudgeon (Flathead and Western), and Murray-Darling rainbow fish.

These results show a marked improvement in native fish numbers following successive wet years. We reported in our January article that the outstanding vegetation response reinforces the importance of environmental water – while current conditions have been influenced by rain, environmental watering provides opportunity.

For the fish, having the ability to manage water events following natural over bank events would allow native populations to sustain. However, this summer has been very hot and dry, and sites across the KP Forest are rapidly drying out. The risk is the next floods will bring carp back into the sites, which is why complementary carp/exotic fish management strategies are necessary to manage the ongoing risk of recolonisation. These strategies could include carp trapping, or fish screens during managed watering events.

Today’s release fits under the Management key themes and interests identified as part of the KP Group of Forest’s community vision (specifically recognition).

For more information contact: Belinda Wielinga, Environmental Project Officer belinda.wielinga@wmlig.org.

This article appeared in The Koondrook and Barham Bridge Newspaper, 13 February 2025.