This newsletter started with a biweekly overview of news in seaweeds. Over time, I realised once a year is really enough, though. This week: what happened in 2025? Next week: what does it mean?
1. Applications
Packaging and plastic alternatives
In 2024, at least $43 million went into 7 different seaweed companies in the broad biopolymer and natural polymer space, Notpla being the biggest beneficiary at $26.8 million. In 2025, the funding kept coming: $10.5 million for Uluu, $2.3 million for Zerocircle and an undisclosed round for pioneers Loliware.
Sway and Loliware both announced partnerships with major North American distributors: Loliware with plastics resin distributor and compounder Entec, Sway with Atlantic Packaging. Notpla revealed it produced around 15 million single-use plastics alternatives in 2025, up from 11.4 million in 2024 and 4.4 million in 2023.
Notable: An industry first, Zerocircle claimed it has achieved price parity with petro-derived chemicals for its food tray coatings.
Biostimulants
Last year I wrote there were too many seaweed-based biostimulant brands, many suffering from a lack of market segmentation in an industry facing commoditization pressures. The seaweed industry largely disagreed with me in 2025 as yet more brands launched general-purpose plant food instead of targeted technical solutions, including Aquabloom (ID) and Ocean Rainforest (US). Big Ag also launched ‘new’ products in close partnership with industry stalwarts: UPL’s Hycoxa (with Goemar) and BASF’s Elite Sea (with Acadian).
Notable: more slept-on approaches did arrive, including Blue Pond’s Agri Fix (roses) and Acadian’s ASM (seed treatment). Also notable: Algas Organics (Saint Lucia / US) became the first startup to pivot away from biostimulants, and the first to go after the pulp market (demand for non-wood pulp is growing at 1 million tons per year), mixing Sargassum with agricultural sidestreams.
Carrageenan and agar
The cycle has finally bottomed out for Kappaphycus and prices started trending upwards again in 2025 after a long post-Covid slump. Recent bad weather in Indonesia is predicted to keep prices elevated in 2026.
Notable: In Tanzania, C-Weed Mwani began construction of a new multi-use processing plant for spinosum (E. denticulatum), while Nutri-San started work on an Ulva processing plant on Pemba (Zanzibar).
South Korea and Japan
Korean seaweed exports surpassed the $1 billion mark for the first time, up 13% year-over-year. To safeguard production in the face of rising sea water temperatures, the government has allocated $25 million to commercialise land-based gim farming by 2029, alongside approving 1,000 hectares of sea space for deep-water trials.
Notable: in Japan too, land-based is seen as part of the solution to offset the loss of traditional resources due to quickly warming waters. Leading land-based companies include Sea Vegetable, growing 30 different seaweed species, and KaisouLab, whose double-crop system combines two species that require different water temperatures for growth.
Food
Consumer packaged goods companies Atlantic Sea Farms, Dutch Seaweed Group, House of Seaweed and Foraged & Found all threw in the towel in 2025, while North Coast Seafood’s Seaweedish Meatballs bucked the trend by securing nationwide distribution and hitting 1 million portions served.
Notable: Seaweed Concept raised 2 million euro, becoming the third European startup (after Moreshrooms and Poseidona) aiming to bring fermented seaweed ingredients to the food market.
Brown seaweeds extracts
Marinova was pleased to close 2025 with record fucoidan production, doubling manufacture in 3 years, and Origin by Ocean announced 11 million euros signed offtake. Many of the startups in the ingredient space, however, continued to struggle with slow sales. Some of the more successful ones announced production expansion (Macro Oceans, Origin by Ocean, Inclita Seaweed Solutions), but those factories remain (unfunded?) and unbuilt as of now.
Alginor’s new alginate plant is nearly finished. In October, the company received another $43 million in loan commitments to deal with major cost overruns.
Notable: One factory did get built. In New Zealand, AgriSea opened the world’s first commercial seaweed nanocellulose biorefinery.
Bioremediation
Pacific Bio opened the world’s first household wastewater treatment plant using seaweeds in Queensland, Australia, filtering 3 million liters per day, with another similar-sized facility planned in New South Wales.
Notable: While research on carrageenan to filter heavy metals and antibiotics from wastewater has been advancing steadily in the past 2 years, broader real-world tests are still lacking.
Restoration
The Kelp Forest Challenge received pledges for 55,000 hectares of restoration and 7,000 hectares of protection to date. South Korea remains the leader in kelp restoration efforts with 29,000 hectares under restoration and a 50% success rate.
SeaForester merged with Seaweed Solutions and received a $1.9 million investment to expand its restoration efforts and develop its kelp nursery platform and suite of monitoring tools, in collaboration with Kongsberg Satellites. Seagrown meanwhile, received a loan.
In regulatory news, the IPCC cleared the path for seaweeds to be formally recognised as a CDR solution. Mexico took a step forward when federal authorities recognized kelp forests as a priority ecosystem for fishing and convened stakeholders to develop a coordinated action plan for kelp forests on the Baja California peninsula.
Fujitsu developed ocean digital twin technology to efficiently quantify blue carbon in seaweed beds, and eDNA could inform blue carbon accounting efforts by helping quantify deposition rates of kelp-derived carbon into marine sediments.
Notable: Norway started a breeding program to restock grey wolf fish to control sea urchin populations, while invasive red king crabs there have emerged as new urchin predators. The stand-out conference presentation I witnessed in 2025 was Jon Dickson talking about tree reefs.
Methane-reducing feed additives
Two Series A rounds were raised by Provectus Algae (photobioreactor production: $10 million) and Symbrosia (PBR + ponds: $5.8 million). Fremantle Seaweed (at-sea) closed a $1.5m seed round. CH4Global (pond-based) received investment from Chipotle.
Notable: Sea Forest listed on the Australian stock market which allowed for a rare peek behind the curtain. What did we learn? The company has pivoted away from seaweed and is transitioning to synthetics. While the company says it will be supplying 118,000 head of livestock by March 2026, income from sales of SeaFeedTM remains very small at around US$325,000 per year.
2. Supply
Wild harvest
Acadian Seaplants closed its Maine operations, representing about 40% of the state’s Ascophyllum industry. Solar dryers started reducing post-harvest losses in Chile. The first autonomous seaweed harvester was launched in Namibia.
Notable: Governments of both Portugal and Spain have for the first time adopted action plans to manage Rugulopteryx okamurae invasions. New research documented the regime shift in Madeira.
Cultivation: temperate seaweeds
Chinese researchers developed a novel triploid breeding method for heat-resistant kelp, and heat tolerance in sugar kelp was found to be predictable at the gametophyte stage, enabling accelerated selective breeding. Genetics work advanced for giant kelp and new gene banks were announced in Maine, US and Chile. Average yields in excess of 15 kg/m were reported at kelp farms both in Europe and the US for the first time.
And a new cultivation technology was presented, growing at sea in clear plastic tubes.
Notable: Canadian Pacifico Seaweeds and partners received CAD$15 million, in part to commercialise its KelpSpat seeding technology.
Cultivation: tropical seaweeds
Genetics work advanced for Kappahycus, and new gene banks were established in the Philippines.
Notable: Among a spate of new vertically integrated companies bringing biostimulants to the market, MarinElixirs (India), SEADLING (Malaysia), Birufinery, BANYU and Zentide (all in Indonesia) received investment.
Phyconomy website news
I have added a seaweed conference calendar. Also new is a directory of seaweed consultants: some of the world’s greatest experts on seaweeds are on it - do check them out if you need help with any of your projects.
Thank you for writing about this! My blog is actually about the latest technology, news and stories of sustainability and climate action, and seaweed has been my latest obsession. I don’t think I ever knew how powerful it really is For our health as well as the planet and how it has the answer to every problem of ours. I tried to understand it’s true role in our fight against the climate crisis, and awareness is step one! Here’s my piece! would love your thoughts on it. https://arshiyaarora.substack.com/p/sus101-seaweed-and-why-it-should?r=3pcwen&utm_medium=ios
Thanks for the summary. As a Commercial Sea Urchin dive harvester here in Santa Barbara, Southern California we are always interested in pro active alternative streams that can supplement our income and can synergise with restoration activities i.e. Outplanting seafloor based seeded lines and spore baskets of Macrocystus Pyreferia to restore and maintain nearshore ecosystem resilience.