Severine Fleming inspects her Smithereen Farm seaweed on Cobscook Bay last year. Fleming co-authored a “warning call” about the potential hazards of unchecked seaweed farming growth worldwide. Courtesy of Severine Fleming

When the two-day Seagriculture Conference came to Portland in September, the first time the Europe-based annual gathering has been held in the United States, a collective of 29 seaweed farmers, scientists and environmental activists from around the world took the opportunity to formally present their concerns about seaweed farming.

Calling themselves Seaweed Commons, the group put forth a position paper “collectively issuing a warning call and demand for regulatory updates to mitigate risks to coastal ecosystems, the commons of the sea, the biodiversity of kelp forests, and the well-being of our human communities.”

Seaweed farmer and activist Severine Fleming of Smithereen Farm in Pembroke, one of five principal authors of the paper, said Seaweed Commons fears that major seaweed aquaculture corporations, lured by the promise of big profits in the years to come, will swoop in to commandeer large swaths of Maine’s coastline.

But the state’s aquaculture industry insiders consider that scenario unlikely. While parts of the U.S. coastline and some countries around the globe face different and tougher challenges to making seaweed cultivation truly sustainable, seaweed farming in Maine is already well-regulated, they say.

“The issue of scale has been a little bit misrepresented in Maine,” Maine Aquaculture Association Executive Director Sebastian Belle said. “Often times, the people concerned about scale will show you a picture of farms in China where you can walk from one raft to another across a bay, pointing out that the farms are so big they’re visible from space. That is just legally impossible to happen in Maine, and would never happen.”

Fears about the future of Maine’s seaweed industry have divided the industry’s proponents. While some are concerned that growing too quickly could result in irreversible damage to the coastline, others worry that, by slowing down, the state will miss out on a crucial economic opportunity that could have a significant positive impact on the environment.


Fleming’s group believes the promise of seaweed cultivation and its potential to help feed the world and save the environment may be overblown.

“We want to protect this space from being captured,” Fleming said after the conference, which was held in Portland because Maine has become a “hot spot for the seaweed industry in North America,” according to its organizers.

“And we want to make sure there’s room for small, locally owned businesses and conservation-minded humans to undertake this work and not be crowded out and outgunned,” Fleming added. “There’s potential for real harm. It’s high stakes, actually.”

“Unless there’s protection for small growers, there won’t be small growers after a certain point in time,” said Paul Molyneaux of Trescott Township, a former commercial fisherman who now writes about sustainable fisheries and aquaculture.

“It’s like handing our oceans over to the corporations,” added Molyneaux, who also signed the Seaweed Commons paper, which draws most of its signatories from well beyond Maine, including the world-famous, pioneering farm-to-table California chef Alice Waters.



Seaweed farming is on the rise both in Maine and worldwide, helping make aquaculture in general – including farmed fish and shellfish – the fastest-growing food production method in the world. The global seaweed cultivation market reached $16.7 billion last year – by comparison, the plant-based meat substitute market was valued at just under $10 billion in 2021 – and industry analysts expect that figure to reach $30.2 billion by 2027, with an annual growth rate of more than 12 percent.

By contrast, all aquaculture in Maine is growing at around 2% annually, Belle said. He added that the state Department of Marine Resources’ permitting process is “very comprehensive,” designed to weed out farms that might disrupt the state’s aquaculture, economy or environment.

“This idea that you’d get hundreds and hundreds of farms jammed into a particular area is just a red herring,” Belle said. “It may happen in other places, but it can’t happen here. The oversight and the checks and balances are in place, and being implemented successfully.”

Belle said aquaculture critics would do well to consider perspective. “We have roughly 1,700 acres leased for aquaculture in the state of Maine, and that’s everything – salmon, mussels, oysters and seaweed,” he said. “Seventeen-hundred acres is equivalent to basically two-and-a-half potato farms in Aroostook County.”

Briana Warner, chief executive officer of Atlantic Sea Farms, which partners with about 30 Maine fishermen to grow kelp, at Pine Point Beach in Scarborough in October. Ben McCanna/Staff Photographer

“The Portland jetport takes up more space than all the seaweed farming area in Maine,” said Briana Warner, CEO of Atlantic Sea Farms, a kelp aquaculture company based in Biddeford. Warner estimated that fewer than 100 acres are farmed for seaweed in Maine.

“What we’re seeing in general in aquaculture is this insidious fear of change,” Warner said. “And when people work from a point of fear rather than a point of knowledge, they create problems that don’t exist.”


Some Maine seaweed scientists said a number of the broad concerns voiced by Seaweed Commons in the international collective’s position paper – including threats to the shellfish industry – don’t necessarily apply to Maine aquaculture at all, where many lobstermen supplement their income by seaweed harvesting.

“The shellfish farmers and seaweed farmers are one and the same group in the Northeast,” said Nichole Price, senior research scientist at Bigelow Laboratories in East Boothbay, whose projects include helping write a 2024 report for the U.S. Congress about the state of seaweed farming science. “So to say that seaweed farming is reducing access for shellfish farming is just ill-informed.”

Price said she can empathize with many of the environmental concerns in the Seaweed Commons paper, like the vulnerability monocultures have to disease and the potential introduction of invasive species that compete for nutrients with the native marine life. But like Belle, she believes Maine’s current seaweed farming regulations already address most of the group’s concerns.

“There are processes in place,” Price said. “If people are worried about large-scale seaweed farms, there’s an avenue for them to talk about it and prevent it.”


Beyond scale, Seaweed Commons activists also fear a massive bait-and-switch underway in seaweed farming worldwide, in which the drive to farm seaweed for food sources for both humans and livestock morphs into biofuel production. The extent to which biofuels, alternative renewable energy sources derived from animal waste or plant material, can benefit the environment and society is yet unclear and unproven, though they’re widely considered to have massive potential.


Still, skepticism remains. “What concerns me is that (seaweed farm proponents) are selling this as food: Kelp is the new kale. But actually, kelp is the new corn ethanol. So it seems disingenuous,” Molyneaux said.

Again, the concern is misplaced with regard to Maine, aquaculture proponents say. “There’s no reality to the idea of producing biofuels in Maine waters,” Warner stated.

Belle said the massive volume of harvest required to produce biofuels would itself disqualify Maine, where farms lack the capacity to meet biofuel manufacturing needs. Moreover, he said the state’s excellent water quality, as measured by the Environmental Protection Agency, ensures that its seaweed harvest can be used for human consumption, unlike other U.S. coastal areas with less clean waters where growing seaweed for biofuels might be given serious consideration.

Fleming said the trajectory of seaweed aquaculture reminds her of short-sighted 20th-century approaches to mining and industrial agriculture, undertaken, as it turned out, to the detriment of the planet’s health. Warner agrees that industrial agriculture is problematic. But to slow seaweed farming growth and await more studies – that Price and others say remain unduly difficult to fund in the U.S. – means Maine would miss a golden opportunity to position itself for the future, both in terms of money and the environment.

“You know who’s not waiting? Fishermen,” Warner said, noting that Atlantic Sea Farms fields five to 10 queries a week from Maine fishermen interested in kelp farming.

“Maine needs to be more resilient, and able to find income sources on the water besides just lobster,” Warner said. “Or in 20 years, we’re all going to look at the coast, and be like, ‘Man, we should have done something.’ In some ways, aquaculture allows us to be who we’ve always been in this state: people who work on water, and rely on natural resources.”



To Warner’s point, more and more of the state’s commercial fishermen, faced with a volatile industry, are exploring ways to diversify their income with seaweed farming.

Robert Baines, 66, has fished for lobster and scallops for more than 40 years. He hasn’t done any spring lobstering for seven years because financially “it wasn’t worthwhile.”

Looking for additional income to cover the loss, he took out an experimental lease three years ago for a nearly four-acre kelp farm off Spruce Head in outer Penobscot Bay. Now, as one of about 30 seaweed farmers partnered with Atlantic Sea Farms, Baines spends four days in the late fall seeding his farm, then harvests the seaweed in the spring before lobster season opens.

“It fits with what I do very well,” said Baines, whose 42-foot boat lets him harvest 10,000 pounds of kelp a day. His boat had already been rigged for scalloping, including with a boom and winch that he now uses to harvest seaweed, so gear like moorings, rope and buoys have been the majority of his investment.

“Every year I’ve improved, and I see room for growth,” Baines said, explaining that he harvested 20,000 pounds his first year, 40,000 the next and 60,000 last year.


“We’re not making a lot of money from this, by any stretch of the imagination,” Baines added quickly. Still, the additional revenue stream has made his business more viable and better positioned for the years to come.

Baines said that while good spots for kelp farms remain, the natural parameters of seaweed farming prevent massive growth. “You can’t put a kelp farm just anywhere,” he said, explaining that the farms need to be protected from winter storms, and can’t interfere with navigation or existing fisheries. “There are limited places up and down the coast you can put a kelp farm in.”

Baines aims to receive a standard lease next year for an eight-acre farm overlapping his current footprint off Spruce Head, which he plans to run with his nephew, Cole Baines. The larger space will allow the Baines team to harvest as much as 120,000 pounds of kelp a year.


As the number of Maine seaweed farmers and the volume of kelp they harvest make steady gains, Bigelow Laboratories continues to partner with Atlantic Sea Farms to study how much atmospheric carbon the sea plants can effectively sequester, and the feasibility of using seaweed in livestock feed to reduce methane output from cows, which contributes to climate change. Early trials have shown that a tropical species of red seaweed used in feed can reduce methane emissions from cattle by more than 80 percent.

“This could have a really meaningful impact on the carbon input to the atmosphere, especially given the number of cows that are farmed not only in Maine but across the globe,” Price said. Still, she cautioned that the approach has its limitations: The tropical rockweed can’t be grown here, and transporting the species around the globe would create a carbon footprint big enough to wipe out any potential gains.


Fleming has strong doubts, asserting that the species of rockweed being studied “can’t be domesticated and scaled at the scale that’s being projected.”

Emily Oakley, an Oklahoma farmer, past member of the National Organic Standards Board and longtime ally of Fleming’s, said she worries about the potential long-term effects of using kelp in fertilizers and livestock feed.

“I think a lot of times organic farmers think – I know I did, at least – ‘I’m doing this really great thing, using kelp, this natural material’ without thinking, ‘Where does this kelp grow, and what role is it performing in this ecosystem where it grows and what happens when we remove it from that ecosystem. What’s the domino effect?’ ”

Warner and others said they understand realistic concerns. But they see more reason for optimism and prudent action. Baines and his fellow kelp farmers say their seaweed sidelines benefit not just their own bottom lines, but the health of the ocean as well. “The seed we put in and the kelp we grow is good for the environment. There’s no harm to the environment at all.”

“This isn’t gloom and doom out there,” Warner said. “The ocean isn’t a place of death, it’s a place of hope and opportunity. We’re not the whole answer, but it really shows that there can be a lot of hope on the water.”

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