Bren Smith is no ordinary waterman. He’s out to revolutionize fishing, fight climate change, create jobs—and get you to eat seaweed.

Bren Smith blends into the New England seascape, a waterman decked out in waders tooling around on his boat in the Long Island Sound. On this hazy July morning, he’s motored out aboard the Mookie III from a Stony Creek, Conn., dock to check on his oyster beds scattered between the Thimble Islands. Another boat putters by, and Smith raises his arm to point, his hands cloaked in rubber gloves to protect against the barnacles. “That guy,” Smith says, “is only catching about five pounds of lobsters a day. He doesn’t even pay for half his fuel with that.” And with this observation, Smith shatters the illusion that he’s just another fisherman chasing his catch.

Smith, in fact, is a genuine revolutionary, a man who sees powerful currents of change in the choppy waters off the Atlantic seaboard. And his neighbor, chugging past with his nearly empty hold, is proof that the end of a way of life is looming—and the beginning of a new one is at hand.

Climate change has affected the fishing beds. Ocean acidification, a product of rising atmospheric CO2 levels, kills off coral reefs, causes toxic algae blooms and dissolves the shells of oysters and other mollusks, researchers say.

And then there’s what Smith calls the “rape and pillage” of the world’s oceans—the overfishing that has dried up once-fertile sources of food, and sent unemployment in once-thriving seaside communities through the roof. Smith assigns himself a share of the blame. He fished for McDonald’s in the Bering Sea some years back, and pushed the cod stocks to the brink. But grousing about it, and hoping government regulation will solve the problem, won’t do the trick. What fishermen catch needs to be rethought. What fishermen should be doing, in Smith’s view, is harvesting kelp.

Yes, you read that right: the slimy brown sea vegetation that has grossed out generations of New England beachgoers. You might think of it as an annoyance of no particular significance to mankind. Smith sees it as a jobs program, an amazing source of nutrition, a strategic adaptation to the havoc being wrought by global warming—and, quite possibly, the next big thing in trendy New York City restaurants.

He calls it his “path of ecological redemption,” and he’s calling on fishermen, businessmen and consumers to follow it with him.

A short, bald man blessed with the ability to sound businesslike and salty at the same time, Smith dropped out of high school at age 14 to become a fisherman, intending to spend his life at sea (even though, as a product of Newfoundland’s icy waters, he never learned to swim). He stuck with it, while finding time to graduate from the University of Vermont and take a law degree from Cornell. In 2002, he leased a plot of shellfish ground, and began growing oysters, mussels, scallops and clams. He started a community-supported fishery program, the first of its kind in the Northeast, supplying subscribers with a package of sustainably grown shellfish once a month during the summer months. Business was rolling along—until back-to-back hurricanes in 2011 and 2012 stuck him with cages full of oysters suffocated by mud. He began looking into species that could both renew their ecosystem and better resist storm surges.

His search was fueled by changes in the waters beneath his boat. The combination of overharvesting and ocean acidification had begun taking a dramatic toll. “There are thousands of boats beached, houses foreclosed, up and down the East Coast, in the gulf, everywhere,” Smith says. “The idea that climate change is an environmental issue has sort of been misbranded. It’s an economic issue.”

Today, he runs what he calls a 3-D sea farm, covering some 20 acres. He harvests seaweed, mussels and scallops near the ocean surface, with oysters and clams in cages further below. He speaks of renewing, rather than depleting, the ecosystem on his watch. But his eyes really light up when he starts talking about kelp. It’s a food source with “more iron than red meat, more calcium than milk and more protein than soybeans,” he intones, on a video accompanying a Kickstarter campaign to raise money in support of his efforts. It’s fuel, for machines—with the potential to one day relieve America’s dependence on oil. And it’s a source of jobs, for a region that desperately needs them. “It’s an industry that doesn’t exist, an industry we can scale up,” Smith tells me.

He’s making headway with his sales pitch. This year alone, he’s been featured in The New Yorker, NPR, The Wall Street Journal, McSweeney’s Lucky Peach, and National Geographic. He’s visited with venture capital investors. He’s teamed up with the Yale Farm, which has helped him spread the word—extending his reach into media and food circles. And lately, he’s been making the 90-mile drive from his patch of ocean to New York City, the bed of his orange pickup packed with kelp in solar-powered coolers, delivering it to a handful of forward-thinking chefs to play around with in their kitchens.

David Santos is a believer. A veteran of the foodie landmark Per Se on Manhattan’s Upper West Side, Santos took to Kickstarter himself to launch his own place, Louro, in the West Village. He’s lined the walls with glass jars of creative combinations of ingredients he steeps for days on end, giving the place the aura of a genial mad scientist’s lab. Sure, seaweed has long been part of a Japanese diet. But Americans need to be led a little. So Santos is sneaking dishes onto VIP and tasting menus—pureeing ribbons of kelp into house-made butter, frying them into tempura, sprinkling them into lemon soup and sautéeing them into a tomato sauce and crab mixture to make an “al diavolo” dish. Not your standard menu, but it’s delicious, at least in Santos’s hands. “Kelp is a better product than kale,” he says. “It’s cheaper, it tastes better, there are more nutrients, and more stuff you can do with it.”

The trick, Santos says, is getting people to try it—maybe even before you fully acquaint them with what it is they’re putting in their mouths. “It’s seaweed. It’s its own worst enemy in a way. We have to get people to understand this is not just stuff that was laying around—this is stuff that was grown with care, treated properly and produced appropriately,” he says.

The toughest sell may be among Smith’s fellow watermen. Persuading them to switch from cod to “sea vegetables” could be tricky, Smith knows. “The kelp is more like farming arugula than chasing things,” he says. “And people think that’s crazy: growing sea vegetables? Fishermen don’t grow veggies! It seems kind of wimpy.”

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The fishermen may take some persuading. But Smith has scientists on his side.

Dr. Charles Yarish, a professor of ecology and evolutionary biology at the University of Connecticut at Stamford, has been researching the ecosystem benefits of kelp for 35 years. In bubbling, white fluorescent-lit tanks in his Stamford lab, two varieties of North Atlantic seaweed—sugar kelp or Saccharina latissima—grow from seed to thread on giant plastic beads. His team uses a system of anchored longlines strung with these beads and planted at three open-water farms—at the mouth of the Bronx River, off the coast of Fairfield, Conn., and on Smith’s Thimble Island farm—to grow plants to maturity and test their potential to clean coastal waters.

Sugar kelp, like oysters, soak up nitrogen, carbon and other excess nutrients through a process called nutrient bioextraction. Using Yarish’s technology and funded by a series of federal grants, Smith and Yarish have been testing a 3-D sea farm model, using the entire water column to produce food for human consumption, rebuild marine ecosystems and clean, nutrient-heavy waters.

A 20-acre oyster farm could compensate for the aquatic nitrogen pollution caused by 350 shoreline residents, and a 20-acre farm of kelp could remove 134 tons of the carbon that causes ocean acidification. Those same 20 acres could also grow 24 tons of kelp in five months. “Mother Nature created these technologies hundreds of millions of years ago, and they actually mitigate the harm we do to the sea,” Smith says. “Our job now is to grow them.”

Jeremy Oldfield, field academic coordinator at the Yale Farm, a sustainable food project affiliated with the New Haven, Conn., university, worked with Smith this summer on developing a kelp-based fertilizer for his tomato crop. Oldfield calls kelp “a preloaded multivitamin for farm soil.” Students at the University of Connecticut School of Business are developing a first-round fuel product, based on a U.S. Department of Energy study that found kelp a rich source of sugar for biofuel.

Smith and Yarish have been working with lawmakers and regulators to suss out how to make the farming process easier. Yarish, his U Conn team, and Maine-based Oceans Approved, LLC, have recently started a training program for new kelp farmers in Maine, Rhode Island, and Connecticut.

In exploring seaweed’s potential, Smith shows an almost missionary zeal. “I’m just thinking about how Bren communicates,” says Oldfield. “He has a great sense of ‘food justice.’…It’s sort of like a manifesto.”

And it’s catching on—in this country and beyond. The Kickstarter campaign Smith launched this summer exceeded expectations. He had hoped to raise enough money to cover the cost of hurricane-resistant anchors, marker buoys, lines, installation and marine licensing fees for seven new longlines wrapped in kelp and mussel seeds. By the time the campaign closed in late July, he’d received donations from 734 people, and raised more than $37,000. By the end of August, all the new longlines had been installed on Smith’s Thimble Island farm.

Cash arrived from all over the world: Myanmar, Ghana, Vietnam and Brazil. Donors wondered if kelp could be used as animal feed, whether his 3-D farm model could work for other species of sea vegetables. “I don’t want to think too big and I’m not the one to do this, but I really think it could be replicated globally if you did an ecosystem analysis based on what could be restorative in each place,” Smith says. In Micronesia, for example, it could be conch, or sponges. “The question is,” he asks, “are we going to be able to model this where we scale it up sustainably, locally, where people own their own farms?”

Closer to home, there are now four new sea farmers awaiting permits in the Long Island Sound. The Bridgeport Regional Vocational Aquaculture School, a high school in Bridgeport, Conn., focusing on marine science, has made progress in procuring a kelp noodle-processing machine. Smith’s fisherman’s co-op has voted to install a kelp seed hatchery, which he hopes will become the first in a series of incubators for investigating value-added products such as fertilizer, cosmetics and biofuel.

In September, on the heels of being named to a list of Social Capital Markets’ global entrepreneurs for 2013, Smith traveled to San Francisco to give a talk on restorative species to a roomful of venture capitalists. At the end of October, he brought down the house at the annual TEDx Bermuda conference, where he discussed how his methods could be exported to Caribbean waters.

And there may be even bigger breakthroughs ahead. Impressed by a sampling of kelp lemon soup, kelp butter and kelp fettuccine with shrimp cooked up by chef Santos, Whole Foods is now exploring ways to get Thimble Island’s products on their shelves by next spring. And sometime next year, if all goes according to plan, attendees at the closing dinner for the International Oceans Conference will dine on kelp—served on White House platters.

Smith clearly enjoys the success, but remains anxious about what comes next—like a parent wary of letting his kid wander too far out of reach.

“My job is to advocate now, and then hopefully there will be hundreds of me, out trying it, perfecting it, innovating, and then I can go back to farming by myself. If I’m the only one talking about this in 10 years I’m going to have failed,” Smith says.