Menindee locals sceptical over Lower Darling River fishway

The NSW Government has spent $5.6m on a temporary fishway at Lower Darling River but only a couple of golden perch have passed through.

The Lower Darling temporary tube fishway at the Lake Wetherell Outlet

Menindee locals are frustrated by NSW Government delays in getting a $5.6m temporary fishway operating on the Lower Darling River – which has seen only a couple of golden perch pass through it into Lake Wetherell over the past month.

Lower Darling temporary tube fishway

The fishway was installed to try and prevent yet another fish kill in the Menindee weir pool this summer, following five such events since 2018.

But Menindee local and Australian Floodplain Association vice chair Graeme McCrabb said “we’ve reached the end of summer and it’s pumped a minimal number of native fish”.

He said locals has raised concerns about the efficiency of the tube fishway, which they were told had only passed a couple of golden perch – “at almost $3m a fish”.

The NSW Government has defended the fishway’s operation, with a spokesman saying it was “premature for any party to be claiming knowledge of (its) operational effectiveness”.

“The system is not yet fully operational, and NSW Fisheries are yet to conduct any analysis of fish moving in the system. This will commence when the unit is in operation.”

Lower Darling temporary tube fishway

But the government has admitted “this is novel technology currently untested at this scale in Australia and on native inland freshwater fish”.

The contract to build the temporary fishway was awarded to Finnish company Fishheart in November, partly on the basis that it is able to use sonar technology and artificial intelligence to differentiate and trap carp, separating them from native fish.

But while the technology offers the opportunity to differentiate and remove carp, the NSW Government says “given the novelty of the Fishheart unit in Australia, the primary focus in year one will be on moving fish upstream and adjusting the technology as needed, with the potential to explore carp separation and removal activities in later years”.

The Scandinavian company has successfully used its technology in Europe and the US to separate and shift fish over dams and other river structures.

Fishheart’s hydraulic fishway produces an attraction flow that lures fish inside its tubing, where AI detects the fish and collects real-time data with photos and video.

If it’s the correct species then the fish is transported in a water-filled tube over the weir, dam or hydropower plant to continue up the river.