The establishment of the Koondrook Weir, located in the mid-Murray River system, has limited the movement between Gunbower Creek and the Murray River for vulnerable and threatened fish species such as the Murray cod and the Golden perch. This lack of fish movement has also stunted potential developments in recreational fishing tourism for the area. Over the past few months however, fish have been on the move at Koondrook with new fishways providing passage for thousands of small and large bodied native fish.
Before the installation of the Koondrook Weir, several diverse fish species from the small-bodied Southern Purple-spotted gudgeon right through to the iconic Murray cod were able to move about freely between the two waterways. This movement was critical for native migratory fish who breed and dwell in differing areas of the river system. The Koondrook weir wall, however, effectively stopped any migration from occurring, with large numbers of fish accumulating at the base of the wall wanting to move upstream.
In recognition of the need to enable fish to migrate and spawn, in late 2021 two new fishways have been installed at the Koondrook and Cohuna Weirs. The two fishways have reconnected 140 kms of the Gunbower Creek to the Murray River, allowing fish to once again move with freedom for the first time in over a century. The Koondrook site features a dual fishway which is an example of a designed management strategy that facilitates the movement of crucial species between the waterways in both low and high flows.
The fishways have two entrances and recent monitoring by the Arthur Rylah Institute (ARI) suggests that the low flow fishway entrance is working effectively, with thousands of native fish recorded moving between the two waterways. In mid-December of 2021, the ARI recorded large numbers of juvenile Silver perch passing through the low flow entrance, as well as Bony bream and small-bodied species including Murray-Darling Rainbowfish, Australian smelt, Carp gudgeon and Unspecked hardyhead.
In late 2022 more monitoring will be undertaken to observe the effectiveness of the high flow fishway entrances. If the low flow data is anything to go off, it looks promising!
Through the implementation of strategies like fishways, there will be increased recovery of iconic species, opening up more room for human recreational activities such as fishing. The investment into supporting fish movements will not only benefit the biodiversity of the river systems and the fish species themselves, but also the human recreational values they serve.
“Recreational anglers see first-hand the benefits of sustainable fishing and improved fish habitats, and this fishway will open up Gunbower Creek to thousands of fish looking to move upstream there.”
The improvement of fish passage between waterways is a key element of the North Central Catchment Management Authority’s Native Fish Recovery Plan. The construction of both fishways was funded by the Victorian Environmental Water Holder, and the Department of Environment, Land, Water and Planning, in partnership with Goulburn-Murray Water. It is evident that native fish need connectivity between aquatic habitats in order to thrive, with the benefits being multi-faceted.
For more information:
- A webinar on the Mid-Murray Recovery Reach by coordinator Peter Rose
Featured image: Aerial view of Koondrook fishway under construction. Source: Goulburn Murray Water.