Pig manure feeding fish

South Australian biotechnologist Andrew Ward is breaking down the waste to create methane, irrigation water and nutrients to feed water fleas, which can become fish meal.

Dr Ward says there is big potential for other animal waste too.

He says it is based on methods already used in many Asian countries.

"Basically reproducing what happens in nature. First you grow the algae, then you feed it to the zooplankton and then to the fish - very much like what happens out [in the] natural environment," he said.

"We just pick the things that are most productive and maximise the productivity of them to make it commercially viable."

Dr Ward says fish food created from the waste of land animals could help reduce the environmental impact of aquaculture.

"A lot of the fish meal currently is coming from wild-caught fish stocks so with an ever-increasing demand in seafood and less wild fish out there, aquaculture has to fill this role," he said.

"Now if we're actually catching wild fish to produce this fish feed then we're not really getting there."