Lukina Lukin with the first harvest of seaweed from her aquaculture lease site.(ABC Eyre Peninsula: Jodie Hamilton)

AUS - Seaweed farmed by Port Lincoln tuna company to become fertiliser, chicken feed and food pigment

Australia's southern coast has 1,500 species of seaweed — the second highest number in the world after Japan — and one Port Lincoln fishing company is harvesting them to make organic products while helping the environment.

In an Australian first, native seaweed is being farmed for liquid fertiliser under a joint SA government and industry research program at Dinko Tuna Farmers finfish aquaculture site in Spencer Gulf.

The seaweed will be made into fertiliser, as well as a pigment worth $US250,000 ($359,000) per kilogram.

The zero-waste process will see the remainder of the solids turned into chicken feed.

The project is also expected to have benefits for nearby tuna, being fattened up in pens for the Japanese sashimi market, as well as other finfish aquaculture such as yellowtail kingfish, by creating cleaner water.

South Australian Research and Development Institute and Dinko Tuna Farmers harvested their first licensed crop of native seaweed in the waters off Port Lincoln in December.

The project stemmed from a desire to tap into the vast seaweed resource and as a way for Dinko Tuna Farmers to utilise the tuna aquaculture site year-round, filling the void after the fish were harvested each winter.

Research that showed there were about 50 to 100 seaweed types naturally growing on mooring anchor ropes for the company's tuna cages, so it was as simple as putting out ropes to encourage wild seaweed growth.

It will be a case of pot luck as to which of the 50 to 100 species will take hold and grow.

In demand

South Australian Primary Industries Minister Clare Scriven said the project had benefits on several levels.

"We know there's a huge demand for seaweed and fish-based fertiliser around the world, in fact it's expected to double by 2031, so this is a big economic opportunity," Ms Scriven said.

"It's also a good environmental opportunity because what this process is doing is actually improving the water quality around aquaculture licences, so this is certainly a win-win."

SARDI Aquaculture leader Sasi Nayar said the seaweed took up nutrients created by tuna farming.

Unlocking the power of marine molecules

They're in salad dressing, toothpaste and household paint. But did you know seaweed extracts can help wounds to heal faster?

Dr Pia Winberg and Professor Gordon Wallace crouch down by the ocean.
They're in salad dressing, toothpaste and household paint. But did you know seaweed extracts can help wounds to heal faster?

"When you co-cultivate this next to tuna farms or finfish farms there is a significant environmental benefit because it is assimilating all the nitrogen and carbon and phosphorous that is potentially discharged from these farms," Dr Nayar said.

"And it goes towards biomass which can be used for a variety of applications, whether it's for food, whether it's for feed, fertiliser or a whole other raft of opportunities that comes with utilisation of the seaweed biomass."

Dinko Tuna Farmers director Lukina Lukin said employment was also a motivating factor.

Creating jobs

The venture aims to secure permanent staff to overcome the seasonal loss of employees each year after the farmed tuna is harvested.

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