SA Water is running a study to better understand the abundance and health of fish populations, helping inform future stocking programs for the benefit of recreational anglers.

The three-year monitoring program will evaluate fish populations at Happy Valley, Myponga and South Para reservoirs, with the South Australian Research and Development Institute (SARDI) leading the initiative together with RecFish SA and SA Water.

Knowledge about the breeding, condition, diet, growth and estimated numbers of stocked native fish species - such as Golden Perch and Murray Cod - will be evaluated across each reservoir, including those of established pest species, including Carp and Redfin.

SA Water’s Senior Manager of Environment and Energy James Crocker said the study provides an insight into the success of the current stocking program, while identifying opportunities to enhance fish stocking at each reservoir.

“An important part of transforming our reservoir reserves into recreational destinations involved establishing a healthy population of native fish species to provide an excellent fishing experience for anglers,” Crocker said.

“This has seen more than 770,000 catch-ready fish and fingerlings released into our reservoirs since 2016 and we now want to invest the time to take stock of how they’re faring in their new homes.

“Together with SARDI and RecFish SA, we’re adopting a similar approach to the fish study recently undertaken at our Warren Reservoir, which enabled the water storage’s gradual emptying as part of a valve upgrade.

“SARDI will be catching both native and noxious fish using a combination of techniques such as rod and reel fishing, netting and electrofishing technology to identify species and record several parameters such as abundance, length and weight.

“A sub-sample of up to 50 fish from each species will also be inspected for any disease and parasites, with all noxious species to be removed from the reservoir, while native fish are returned to the water.

“Early insights from the first stage of monitoring showed Rainbow Trout - recently released into Myponga - had dispersed throughout the entire reservoir, while an abundance of prey species were found at South Para.

“Importantly, they have also identified our stocked native fish are in excellent health, and approximately 25 to 30 per cent heavier than fish of the same length found in the River Murray.

“With a diversity of thriving fish already being reeled in, we’re hoping the findings from this work will refine our stocking program to help sustain healthy native populations and get even more bites for our anglers.”

Monitoring will begin at Happy Valley Reservoir during the winter months next year, after it was stocked for the first time in 2021.