Hawaii seaweed seen as likely solution to cattle methane emissions

Limu kohu is most traditionally destined for poke bowls, but the distinctive-tasting seaweed is now increasingly in demand for cattle to reduce the amount of methane they burp into the atmosphere.

Parker Ranch cattle are among the first of Hawaii’s livestock to be fed farmed red algae in a trial, which over the past six months reduced the amount of methane the animals belched by an average of 77 per cent, according to Kona-based business Symbrosia.

The algae’s ability to mitigate cattle’s greenhouse gas emissions has elevated Symbrosia and Blue Ocean Barns, another limu kohu farm based in Kona, in the growing international seaweed farming industry.

Fuelled by its litany of potential applications and climate change-mitigating properties, the World Bank predicts the industry could be worth almost US$12 billion by 2030. And that is attracting immense public and private investment interest across the globe, including in Hawaii.

The federal government awarded Symbrosia more than US$2.2 million in grant funding this year, including a US Department of Agriculture organic market development grant for US$1.2 million late last month.

That catalytic funding will increase the 5-year-old operation’s production by 1,600 per cent, Symbrosia CEO Alexia Akbay said. That means just over 6,000 cattle could be eating Seagraze, the red algae product, as part of their diet. The cap is currently 250 cattle.

With a US$1 million grant from the National Science Foundation, awarded in January, it plans to streamline its currently labour-intensive production process, one that involves three stages of finicky cultivation and drying.

Blue Ocean Barns signed on with two major mainland dairies, as well as ice-cream producers Ben & Jerry’s, raising US$20 million. Symbrosia last year signed on with Organic Valley, the nation’s largest farmers cooperative, and Danone, the country’s largest yoghurt producer.

Expanding commercially

The recent injection is “really the next step for us to start expanding commercially for our products, for both local producers like Parker Ranch and then some larger companies like Organic Valley,” Akbay said.

But the company does not appear to be leaving any time soon, given the growing conditions and Hawaii’s unique climate. Symbrosia is expanding its footprint from one-quarter acre to 15 acres and looking to increase its staff by 70 positions, Akbay said.

That’s partly because of the year-round growing climate for the seaweed farm.

“We probably harvest a little bit more frequently, ship out product more frequently, just because the seaweed grows so quickly,” Akbay said.

But now the race is on to commercialise and scale the product across the world, given how high demand might be in the future, says Jim Wyban, who developed pathogen-free shrimp which underpins the global shrimp industry.

Major dairy and beef producers worldwide have started expressing serious interest in methane-reducing seaweed since researchers in Australia discovered its potential. The country’s first commercial harvest was in 2022.

Meanwhile, the Global Methane Pledge, with 155 signatory nations, specifically targets livestock because they contribute the bulk of agriculture’s emissions. And agriculture accounts for 37 per cent of the world’s total methane discharged by humans.

A single cow produces between 154 to 264 pounds of methane per year. The United States, which commands a 20 per cent share of the international beef industry, has a cattle population of more than 87 million.

“They’re going after a really big problem,” Wyban, a leader in Hawaii’s aquaculture industry, said of the seaweed companies.

The global market for seaweed-based animal feed supplements could be worth US$1.1 billion by 2030, according to the World Bank.

There has been local interest beyond Parker Ranch, Hawaii Cattlemen’s Council managing director Nicole Galase said. But many ranchers want to see results first, Galase said.

Symbrosia’s research with Parker Ranch is slated to last nine more months. The red seaweed has been associated with faster weight gain in cattle, more milk production and even faster wool production in sheep.

“We want this research and ingenuity coming up because we do want options. Ranchers are always looking for a way to improve,” Galase said. “That takes research, that takes people trying things.”

But having a locally-grown and produced product is not going to keep more livestock in Hawaii, where a large proportion of cattle are shipped to the mainland. The number of cattle shipped to the continental US is mainly determined by how much grass Hawaii has at any given time, a factor largely dictated by drought, Galase said.

There are several other algae-based markets, including construction materials, fertilisers and other agricultural inputs, bioplastics, biofuels and fabric.

Each represents an opportunity for greater environmental and economic sustainability, said Todd Low of the state Department of Agriculture.

“There’s three kinds of value to seaweed: There’s the ecosystem services, the filtering of water and benefits to the environment. There’s carbon sequestration … then there’s this value-added processing,” Low said.

Algae already sits just behind cattle as Hawaii’s fifth most valuable agricultural crop. It was worth US$45 million in 2022. Hawaii’s entire aquaculture sector is anticipated to reach US$600 million by 2034, according to the Department of Agriculture.

“There’s a whole world of different value-added things,” Low said. “For us, the focus on macro-algae or seaweed is the vehicle into that world.”

This story was originally published by Honolulu Civil Beat and distributed through a partnership with The Associated Press.