Southern Seagreens, Flinders, prepare to harvest macrocystis crop

Three friends Cam Hines, Brent "Bert" Cross and Rob Brimblecombe took the plunge to build Australia's first commercial macrocystis farm, named Southern Seagreens.

Macrocystis is a large brown algae, also known as giant kelp, and will be ready for harvest in the coming weeks at an aquaculture site near Flinders.

Alongside their sown seaweed farm, they have just finished the wakame harvesting season, which is an introduced and classified invasive species in Australia.

The removal of wakame, undaria pinnatifida, helps promote the growth of golden kelp, or ecklonia radiata, a native species which grows on beds in reefs, and can form dense sea forests.

Mr Hines said the species was "opportunistic" and grew quickly, and they had to apply for a licence to commercially harvest wild wakame.

Mr Cross said he initially felt inspired to be part of the seaweed farming industry after watching a documentary, 2040.

The documentary mentioned kelp farming and its benefits including carbon removal, improving nearby ecosystems and aiding in re-establishing native kelp populations

"I just left the cinema going 'I could totally do that'," he said.

He said they planned a small site with Victorian Fisheries Authority in an aquaculture zone at Flinders, to test the application of seaweed farming.

"We threw some rope in the water to see what would naturally grow, and also what sort of species we might be competing with," he said.

Mr Cross said they were fortunate with their expertise between the three.

He owned a diver's licence and managed a commercial diving business, Mr Hines had business management expertise and grew up on a Shoreham farm, and Mr Brimblecombe studied a degree in plant genetics and a doctorate in bio-inspired solar.

"We've got the capability and the know-how to do the on-water things, Cam had the time to do the back end, so it just meshed beautifully," Mr Cross said.

He said a key challenge included finding the seed source to use for their farm, and understanding the end use for the kelp.

Mr Hines initially discovered Mr Cross's plan and aspirations after hearing a radio interview when he was researching seaweed farming.

He said he had sold his brewery business earlier, had come across a similar documentary on seaweed and felt inspired to research the practice.

Mr Hines said they focused on how to execute the seaweed farm affordably, resourcefully and sustainably.

"We get PVC pipe from Bunnings and chop it into sections, wrap twine around it and sterilise it, and before we know it we've got kelp baby sporophytes growing on the twine," he said.

"If you give it dream conditions, the right temperature, the right way, the right amount of nutrients in sterile water, it'll grow.

"And we've learnt how to do that."

Sporophyte is the diploid phase in the life cycle of a plant or algae, meaning it produces spores for growth.

Mr Cross said he would describe the farm as three-dimensional, with horizontal ropes to hang seaweed, secured by anchors.

It also meant the farm had the ability to change the depth of the ropes for sunlight access and ideal water temperature to avoid bleaching.

They manage five farms with an array of about 750 metres of lines overall, at a three-hectare site.

Mr Hines said they currently had a 12-month permit to farm macrocystis, but hoped they could eventually secure a permanent permit for their farm.

Currently, native seaweed harvesting in Victorian marine waters is prohibited without a permit under the Victorian Fisheries Authority.

Mr Hines said native kelp helped de-acidify seawater and maintain a healthier pH balance.

He said its nutritional values included higher calcium than milk and more iron than red meat.

"Chefs are showing us they can use it in all these amazing, different ways," Mr Hines said.

"We're working out how to breed it, how to farm it, how to dry it commercially and then how to get it to market and introduce in a way where Australians start embracing it in a more day-to-day sense."

Mr Hines said they classified themselves as a form of regenerative agriculture through improving the marine ecosystem, taking carbon out of the atmosphere and water, and having a lack of inputs.

"This requires no fertilisers, no pesticides, no arable land or fresh water," he said.

"We're giving native kelp, golden kelp, a chance to regain a foothold."

He said their longer-term goals included investing in an electric boat and electric truck to avoid using diesel, power their drying facilities with solar energy, and more.

Mr Cross said they would now prepare to harvest their first crop of macrocystis, which seemed "fairly straightforward", it had the potential to regrow after harvest.

"The first few lots of our plantings didn't succeed, and we were scratching our heads and started to get a bit worried," he said.

"We had a really healthy set of seed lines, and we put them out on the water and they sat there and sat there.

"Then they just went 'pop', and started growing, and they all went gangbusters.

"We went from an utter dismal feeling, to elation."