Great Darling Anabranch 2017
Posted: 14 May 2020
Golden perch or ‘yellowbelly’ are one of the main large-bodied native fish that support the freshwater recreational fishing industry. Golden perch are also of high cultural importance for many First Nations.
In 2016, natural floods in Queensland and northern NSW, along with water for the environment triggered a large spawning of golden perch. The fish larvae drifted down the Darling River and ended up in the Menindee Lakes. Some larvae kept traveling down into the Lower Darling.
Menindee Lakes are a known nursery for yellowbelly, where baby fish get fattened up in the highly productive water. These lake fish are bigger and fatter than their river counterparts.
Fish scientists, water managers and river operators worked closely with the local community to time flows out of the Menindee Lakes system to support the dispersal of golden perch both into the Lower Darling River and the Great Darling Anabranch.
Juvenile Golden Perch Lake Menindee 2017
Water for the environment was particularly important for the flows from Lake Cawndilla—the lowest lake in Menindee system—into the Great Darling Anabranch. 100 GL (gigalitres) of water for the environment was used to provide a flow down the dry riverbed and allow these fish to reach to the River Murray. Without this flow, hundreds of thousands of yellowbelly fingerlings would have been stranded in Lake Cawndilla and as the lakes dried out, they would have turned into bird food.
A fish survey in 2018 showed that around 36% of the total golden perch population in the Lower Darling were spawned in the 2016 breeding event.
In 2020, scientists have found new populations of golden perch larvae floating down the Darling River as a result of the recent flows. So, there may be an opportunity to do this again in the coming year!
Golden perch that spawn in the Darling are really important to the whole of the southern Basin. Science—measuring fish ear bones—has shown that golden perch which spawn in the Darling often make up a large percentage of the total golden perch population in the River Murray. In fact, golden perch from the Darling also migrate upstream to the Edward-Wakool (NSW) and Goulburn Rivers (Vic).
The story is not so good further downstream. Over the past five years, CEWO’s monitoring program has found very little evidence of golden perch recruitment—fish spawning that results in new individuals in the population—in the South Australian Lower Murray. This highlights the importance of using environmental water to support golden perch spawning events in the Darling River.