A new fish ladder/fishway has opened recently at the Tauwitcherie Barrage near Goolwa.
It has been developed in order to improve migration between the Coorong and Lower Lakes. It has been predicted that hundreds of thousands of fish will begin to swim through the passage.
The fishway will allow native fish to swim through the structures throughout the River Murray as well as its tributaries. This will allow them to breed after accessing a new habitat.
SA Water undertook the project in the name of the Murray-Darling Basin Authority. Costing $250,000, the project is a part of a program that works to develop fishways before allowing free migration.
This begins from the Southern Ocean in South Australia, upstream to Hume Dam near Albury-Wodonga.
Senior manager of River Murray Operations Garry Fyfe of SA Water said the early fishways were constructed in areas of France during the 17th century in order to create steps in steep channels, bypassing obstructions within local rivers.
“The idea around modern fishways is still pretty much the same, but these days we use mostly precast concrete,” Mr Fyfe said.
The various designs will be based on aspects regarding the local river conditions. The physical characteristics and swimming abilities of the fish that will migrate throughout the area will also be taken into account.
“At Tauwitcherie, we’ve installed a trapezoidal fishway that can operate over a wide range of water levels to target the movement of both small and large fish,” Mr Fyfe said.
The trapezoidal fishway has been divided into a number of interconnected pools on a straight channel, slowing down the flow of water. This makes the fish travel through it with ease.
The pools have areas that are of high and low velocity water, suiting the movement of fish that are different sizes.
“This is the fourth fishway to be constructed at Tauwitchere Barrage and at only 4m wide and 15m long, is relatively small in comparison to the 3.6km long barrage,” he said.
A total of six fishways have been constructed through the Commenwealth-funded construction of Fishways Management Action under the Coorong.
The Tauwitcherie fishway is the last of the six as a part of the Lower Lakes and Murray Mouth recovery project.
Freshwater species including the Australian Smelt, Bony Herring and Golden Perch will swim through the fishways. The diadromous species like Congoli will also swim through the fishways after moving between the ocean and river, completing their life cycle.