Back where they belong, Murray Cod bring new life to SA's Lake Bonney

In short:

Hundreds of Murray Cod are now inhabiting Lake Bonney at Barmera after a special release of the fish coordinated by RecFish SA.

Many of the fish are ready to breed, so numbers can grow quickly in the coming months.

What's next?

The release is hoped to rejuvenate the local ecosystem and boost tourism in the region.

A freshwater lake is hoped to become a thriving ecosystem after hundreds of mature native Murray Cod were reintroduced to its waters for the first time in years.

Around 600 cod were returned to Lake Bonney, which is connected to the River Murray, in South Australia's Riverland last week.

It was a project driven by Recfish SA and backed by the state government and its newly established Recreational Fishing Authority.

RecFish SA chief executive Asher Dezsery said it was a significant moment to see cod enter the water, as populations had died out from the lake many years prior.

"Throughout various water quality issues, the lake got segregated from the river, and unfortunately there were a few fish kills here that removed all of the cod," he said.

"These are big fish, they're not fingerlings, these are up to a metre.

"They're going to be instant broodstock [mature individuals specifically used for breeding], creating an instant fishery to push recreational fishing tourism in this area."

New natives to improve ecosystem

Charles Sturt University's Paul Humphries said cod defined the Murray-Darling Basin and its connected systems.

"They will improve generally the water, the structure and the water quality, because they actually are, to a degree, habitat engineers," the ecology associate professor said.

Dr Humphries also said cod played a major role in the natural food chain, but was not certain they would make a dent in the large carp population.

"If there's small fish around, like carp, they'll certainly have a go at them. [But] cod tend to be main channel specialists," he said.

"Carp are such prolific breeders. It's not something that can be solved very easily by just throwing a few hundred cod in, but it certainly can't hurt."

For Ngintait elder Norman Wilson, the lake and the Murray Cod are culturally significant.

He said he hoped some of the fish would migrate into the river system but believed they would return to breed.

"That's their cycle; they'll always come back to the same place [so] there's going to be cod here at all times," he said.

Council hopeful for tourism boost

Berri Barmera Council mayor Ella Winnall was among the locals who helped return the native cod to Lake Bonney at a special event in early October.

She said it was a "once in a lifetime opportunity" to be up close with so many mature cod, giving locals and visitors another reason to spend time at the lake.

"There aren't many people in the community that don't have a rod and reel in the shed or a boat licence," Ms Winnall said.

"This just adds another element of people wanting to come to Lake Bonney and Barmera to catch the cod."

Fishing for Murray Cod is not allowed during the breeding season, but South Australia's catch-and-release season resumes from January 1, 2027.