I still remember the first time I ate fresh kelp. I was visiting a small regenerative ocean farm off the coast of Devon, standing on a gently bobbing boat with rain spitting in my face (classic British coastal weather), when the farmer casually tore off a piece of glistening, just-harvested sugar kelp and handed it to me. “Try it raw,” he suggested, looking amused at my obvious hesitation. I’d eaten seaweed before, of course – those little crispy nori snack packets that got me through countless deadline nights, and various seaweed salads at Japanese restaurants. But never something pulled straight from the ocean minutes earlier.
It was nothing like I expected – tender but crunchy, with a briny sweetness that tasted like the essence of the sea but without the fishiness I’d anticipated. My surprised delight must have shown on my face because the farmer, James, laughed and said, “That’s how everyone reacts. They think it’ll be slimy or fishy, but it’s just… fresh.” Four hours later, I was still on his boat, soaked to the skin but completely captivated by what he was growing beneath the waves – not just kelp, but mussels, oysters, and scallops, all in a system that required no fertilizer, no freshwater, no pesticides, and actually improved the surrounding ocean environment rather than depleting it.
That day changed how I think about food production. I’d spent years researching and writing about sustainable agriculture, focusing almost exclusively on land-based systems – regenerative farming, permaculture, urban gardens, vertical farms. But standing on that boat, watching James tend to his underwater crops with the care and knowledge of any skilled farmer, I realized I’d been missing perhaps the most promising frontier of sustainable food production: the 71% of our planet covered in water.
The concept of ocean farming (or regenerative aquaculture, to use the fancier term) is actually ancient. Indigenous coastal communities worldwide have practiced various forms of shellfish and seaweed cultivation for thousands of years. But the modern iteration, designed specifically to address our current environmental and food security challenges, is relatively new and evolving rapidly.
Unlike conventional aquaculture (think salmon farms with their concentrated waste, antibiotics, and feed requirements), regenerative ocean farming mimics natural ecosystems while producing food. The basic model uses the entire water column – anchored lines grow kelp and other seaweeds near the surface where they can access sunlight, while shellfish like mussels, oysters, and scallops grow at different depths below. It’s essentially three-dimensional farming, producing more food per acre than any land-based system could dream of.
But the real magic is in what these farms don’t need. No fertilizer – seaweeds absorb dissolved nutrients directly from seawater. No irrigation – obviously. No pesticides or herbicides – proper spacing and species selection naturally minimize pests and diseases. No weeding, no tilling, no tractors burning diesel fuel. The input-output ratio makes traditional agriculture look absurdly inefficient by comparison.
And the benefits go far beyond just growing food efficiently. Kelp forests – whether natural or farmed – are incredible carbon sinks, absorbing up to 20 times more carbon per acre than forests on land. They also reduce ocean acidification by absorbing CO₂ from the surrounding seawater, creating protective pockets of less acidic water that help shellfish form their calcium carbonate shells (increasingly difficult as our oceans acidify due to climate change).
Shellfish, meanwhile, are nature’s water filters. A single oyster can filter up to 50 gallons of seawater daily, removing nitrogen and other pollutants while improving water clarity and quality. Mussel beds create habitat complexity that supports marine biodiversity. The whole system functions as a sort of underwater permaculture, with each species playing multiple roles in creating a resilient ecosystem that happens to produce nutritious human food.
After my rain-soaked epiphany in Devon, I became slightly obsessed with ocean farming. I started visiting other operations around the UK coast, then ventured further to interview pioneers in the field. This culminated in a somewhat impulsive journey to Connecticut to meet Bren Smith, the former commercial fisherman who developed the regenerative ocean farming model now known as 3D ocean farming through his organization GreenWave.
Bren’s story is fascinating – he spent years as a conventional fisherman, participating in what he now calls “the robbery of the commons” as industrial fishing depleted one species after another. His transition to ocean farmer came partly from necessity as fisheries collapsed, and partly from a growing ecological awareness. When he showed me his farm in the Long Island Sound, I was struck by how unimpressive it looked on the surface – just a few buoys marking the boundaries, with most of the action happening invisibly beneath the waves.
“That’s part of the point,” he explained as we hauled up a line heavy with blue mussels. “Low aesthetic impact, low capital investment, high yield.” The startup costs for a small ocean farm run about £20,000-30,000 – accessible to far more people than the millions required to buy farmland in most parts of the UK. And these farms can become profitable within two to three years, producing several tons of seafood annually on just a few acres.
What strikes me most about ocean farming is how it inverts many of our assumptions about food production. On land, monocultures are problematic but common, while polycultures (growing multiple species together) remain relatively niche. In the ocean, polyculture isn’t just preferable – it’s almost necessary for farm success. Different species perform different ecological functions, creating a balanced system that’s more resistant to disease and environmental stressors.
The economic model is different too. Most ocean farmers I’ve interviewed don’t specialize in a single crop like land farmers often do. Instead, they grow a portfolio of species that provide income throughout the year – kelp harvested in spring, oysters and mussels available year-round but with peak seasons, specialized seaweeds with different growing calendars. This diversity provides financial resilience alongside ecological benefits.
The nutritional profile of ocean-farmed foods is another revelation. Seaweeds contain more minerals than just about any terrestrial vegetable, along with omega-3 fatty acids typically found only in fish (who get them by eating… seaweed and algae). Shellfish provide protein comparable to meat but with significantly less environmental impact. We’re talking about some of the most nutrient-dense foods on the planet, grown with minimal resources.
Of course, ocean farming isn’t without challenges. Site selection is critical – water quality, temperature, nutrient levels, current patterns, and existing marine activity all influence farm success. Regulatory frameworks haven’t kept pace with the industry’s development, creating bureaucratic hurdles for many aspiring ocean farmers. Processing and distribution infrastructure is still limited in many regions. And there’s the simple fact that many consumers don’t yet know what to do with a bag of fresh kelp or how to prepare different shellfish.
That last challenge – the culinary learning curve – is actually where I’ve found myself getting most involved. After visiting various ocean farms, I started experimenting with their products in my kitchen, developing recipes and techniques that make these ingredients approachable for everyday cooking. I’ve hosted seaweed dinner parties for skeptical friends, collaborated with local chefs on kelp-focused menus, and even taught community workshops on incorporating ocean-farmed foods into familiar dishes.
My favorite conversion story involves my dad, who views most of my environmental interests with amused tolerance but draws the line at changing his meat-and-potatoes eating habits. I added shredded kelp to his beef stew without telling him, letting the umami-rich seaweed amplify the savory flavors he loves. He had seconds and then thirds before I revealed my sneaky ingredient addition. Now he actually requests “that seaweed stuff” when I make stew, which feels like a small but significant victory.
The scaling potential of ocean farming is where things get really interesting. Current estimates suggest that farming just 5% of U.S. waters could produce the protein equivalent of 2.3 trillion cheeseburgers – enough to feed the American population several times over. If we applied similar approaches globally, we could theoretically meet a significant portion of human food needs while simultaneously improving ocean health, sequestering carbon, and reducing pressure on terrestrial ecosystems.
But the future of ocean farming isn’t just about massive scaling – it’s also about integration with other systems. I recently visited an operation in Scotland that’s developing an innovative circular model: waste from their salmon aquaculture (a more conventional approach) provides nutrients for their kelp and shellfish farms, which in turn help clean the water around the salmon pens. The kelp is partially harvested for human food, with the remainder used to make fish feed for the salmon – replacing the wild-caught fish typically used in aquaculture feed and closing the loop.
Another project in the Netherlands is combining offshore wind energy with seaweed farming, using the same ocean space for both renewable energy and food production. The turbine structures provide attachment points for seaweed cultivation, while the farm maintenance can be coordinated with turbine maintenance to reduce operational costs. This kind of integrated thinking – finding synergies between seemingly separate systems – represents the most promising pathway for ocean farming’s future.
For those interested in supporting ocean farming without becoming farmers themselves, the simplest approach is to start incorporating these foods into your diet. Ask at farmers markets whether any local producers offer ocean-farmed products. Look for restaurants highlighting these ingredients on their menus. Try cooking with dried seaweeds if fresh isn’t available in your area – even products from conventional seaweed harvesting (not necessarily regenerative farming) generally have lower environmental footprints than land-based alternatives.
I’ve also watched with interest as non-food applications for farmed kelp develop – from compostable packaging materials to organic fertilizers for land-based agriculture. These additional market streams help make ocean farming more economically viable while extending its environmental benefits beyond the food system.
What began for me as a rain-soaked revelation on a small boat has evolved into a fundamental reconsideration of our food system’s future. When we think about feeding a growing population in a changing climate, our gaze typically turns to land – how to farm more efficiently, how to reduce waste, how to make better choices between the options visible on our supermarket shelves. But perhaps we should be looking instead to the horizon, to the 71% of our planet that could produce food while restoring rather than depleting natural systems.
Last month, I returned to James’s farm in Devon – this time on a surprisingly sunny day that turned the water a brilliant blue. We harvested sugar kelp together, the slick fronds piling up in the bottom of his small boat. “You know what the best thing about this work is?” he asked, pausing to look out across the water. “I’m not just taking from the ocean anymore. I’m giving something back.” As we navigate the complex challenges of creating truly sustainable food systems, that reciprocal relationship with our planet’s ecosystems might be the most important crop of all.
