When it comes to their neighbors in Norway, the good people of Denmark and Sweden have a limitless fount of jokes, many of which are reductive and in questionable taste; none of which should, under any circumstance, be repeated.

Here’s one of the funniest:

A Dane, a Swede and a Norwegian are shipwrecked on a desert island. The Dane finds a magic shell, which, when rubbed, entitles each of the castaways to a wish. The Dane says: “I wish to go home to my cozy flat in Copenhagen and relax on my soft sofa beside my sexy girlfriend with a six-pack of beer.” He promptly disappears. The Swede says, “I wish to return to my large and comfortable Stockholm bungalow, with its sleek Ikea furniture.” He vanishes, too. After mulling his options, the Norwegian says,

“I’m terribly lonely now. I wish my two friends were here with me.”

For much of the last decade, Roderick Sloan has been viewed as something of a Norwegian joke. By Norwegians, no less. The 44-year-old émigré Scot makes his home 88 miles north of the Arctic Circle—little more than a cod’s toss from Nordskot (pop. 55), one of Norway’s darkest, bleakest, remotest coastal villages.

The farm he shares with his wife (Lindis), young sons (names withheld by request) and dog (Sisko, an aged Labrador with bad joints and a worse aroma) spans 500 scraggly acres. The land is speckled with birch and encircled by mountain—lofty, sharp-edged and shaped like dragon’s teeth. It’s an agreeable enough place in what American travel writer Bill Bryson might call a thank-you-God-for-not-making-me-live-here sort of way. “Summer is special in Nordskot,” cracks Christopher Sjuve, an Oslo-based wine blogger. “It’s everyone’s favorite day of the year.”

Sloan embraces the isolation. “I love the tranquility here, you understand,” he says in a soft Scottish burr, rolling his r’s and stretching out his vowels. “I love the clean air and the changes of the seasons. It’s not perfection, but then if life is too perfect, it can be perfectly dull.”

What makes Sloan perfectly risible in the eyes of many is the precarious career he has carved. In weather that would be considered mild only on Neptune, he dives into the icy fjord to gather sea urchins, those wee beasties that look like squash balls encased in pine thistles. Sloan’s aquatic treasure hunts for krakebolle (“crow’s balls” in Norwegian) are as dangerous as they are daring. Waves are often treacherous; squalls, gusty; and storms can appear in an instant. “Roddie swims alone, down to 50 feet deep,” Sjuve observes. “You’ve either got to be drunk or crazy to do what he does.”

Crazy, say the locals. “When I started to harvest urchins in 2002, everyone thought I was bananas,” Sloan says. “They’re not a traditional catch in north Norway.” He means urchins, not bananas. Though plentiful, urchins are not exactly standard fare in Norway, a nation of largely unadventurous eaters who annually consume 48 million frozen pizzas—about 10 per capita. Sloan is practically a cottage industry unto himself. “We’ve got seals and killer whales,” he says, “but I’m the country’s only full-time urchin diver.”

In the brave new world of fine dining, the roe of the humble urchin—a shellfish once cursed as a pest to lobstermen, mocked as “whore’s eggs” and routinely smashed with hammers or tossed overboard as unsalable “bycatch”—is a prized and slurpily lascivious delicacy. Unlike caviar, which is the eggs of fish, the roe of the urchin is its wobbly gonads. Every year more than 100,000 tons of them slide down discerning throats, mainly in France and Japan, where the chunks of salty, grainy custard are known as uni and believed to be an uplifting tonic, if not an aphrodisiac. The Japanese exchange urchins as gifts during New Year celebrations.

Sloan supplies Strongylocentrotus droebachiensis, or “Norwegian greens,” to dozens of the most revered restaurants in Europe, from London’s meaty, masculine mecca of English food (St. John) to the 12-seat Fäviken in the wilds of northern Sweden, where chef Magnus Nilsson stalks lingonberries in bearskin with his gun dog, Krut.

Master chefs buzz among themselves about Sloan’s urchins like discoverers of a latter-day Beatles—or, in the case of René Redzepi, beetles. The founder of “New Nordic” cuisine, Redzepi runs Noma, a Copenhagen eatery that Restaurant magazine has judged to be the world’s best in four of the last five years.

Redzepi’s 28-course celebration of local and seasonal ingredients foraged from the woodlands and seashore is designed to demonstrate nature on a plate. He fashions culinary bouquets from wild herbs and edible soil, toasted hay and reindeer moss, live ants and fermented grasshoppers. (“Waiter, there’s a fly in my soup!” “Yes, and for the next course...”) In one signature dish, raw North Atlantic shrimp are washed up on a “beachscape” of grasses, frozen pebbles and dried-urchin “sand” that showcases the Norwegian green’s murky orange innards. Sloan provides the urchins, which the Danish have dubbed søpindsvin (sea hedgehogs). Redzepi says they’re as luscious as anything he’s ever eaten.

“It’s like Roddie invented a new product, a new culinary sensation,” echoes fellow chef Esben Holmboe Bang, whose Maaemo is the most shimmering of Oslo’s Michelin-starred chow houses. “His Norwegian greens are sweet and tender and you can taste the wilderness in every bite. It’s like you’re making out with the sea.”

***

The night before the greens first appeared on Noma’s menu, a waiter asked, “Where do sea urchins come from?”

“They grow on trees,” said another waiter, helpfully. Which even by Scandinavian standards wasn’t much of a comeback. It so happens that urchins can be found in almost every major marine habitat from the poles to the Equator, and from shallow inlets to depths of more than 17,000 feet. Sloan mostly targets exposed reefs with rich forests of kelp, which urchins eat ravenously.

At dawn on this brutal spring morning, Sloan and his one-man crew—a Frenchman who answers to J.C.—clamber onto a red polar work boat he’s christened Big Betty. Out to sea, a white-tailed eagle is wheeling and, beyond that, to the northwest, you can see the lumpy peninsula jutting toward the Lofoten Islands. Under an immense sky (sea clear, light swell) Big Betty putters along until reaching a craggy cove, where Sloan spies the familiar dark shadows. He zips up his dry suit, yanks on rubber gloves and straps on 65 pounds of scuba gear. Plopping backward into the water, Sloan shimmies through dense clusters of seaweed, propelled by the surge of each wave.

Urchins have hundreds of adhesive tube feet and move over the sandy seafloor at a fairly leisurely pace. Sloan collects them with diligence and a certain tenderness, placing the prickly krakebolle one by one into the mesh sacks that flutter in his wake. After 30 minutes he surfaces through the surf, and is quickly hauled onto the deck by J.C., who then sorts the urchins according to color, size and condition. A typical daily haul is between 200 and 300 pounds.

Sloan’s frozen lips are the same pale blue as the water; his breathing is so labored he can barely speak. “Welcome to my office,” he says at last. “This is a magic place to be. Every day I feel like I’m parachuting into the Amazon jungle, without the piranhas. I have no idea what’s going to happen. It’s quite exciting, but it can be terrifying as well.”

He smiles gently. Sloan is an engagingly modest, gruff and diffident fellow with an untamed beard and a sharp sense of humor—in three languages. “I’m quite a sane guy,” he says, “but I’m a bit mad, too.” He’s never bothered to pry out the urchin spike his right thumb has harbored since 2004. “The first year it’s interesting. After that, it becomes part of you.”

The English writer P. G. Wodehouse wrote that it’s never difficult to distinguish between a Scotsman with a grievance and a ray of sunshine. Though Sloan has a copious supply of inner sunshine, he holds strong opinions—about politicians, whaling, the sustainable and ethical consumption of fish, the 1970s TV spy show “The Man From Atlantis” (which he loves), Nordic mosquitoes (hates), the medicinal value of periwinkles—and he doesn’t hesitate to express them. If he invites you to spend a day aboard Big Betty, then you’ve passed some very stringent, very idiosyncratic test of character.

At this moment he’s standing astride Betty’s stern, holding forth on the perils of his profession. He recalls a five-hour battle through 20-foot waves to get his first tiny boat the final kilometer home. (“If you steer the wrong way, you die. It’s as simple as that.”) He compares disentangling himself from a clump of underwater kelp to squeezing through a hawthorn hedge. He describes being flung into a churning washing machine of surf and currents. “I’m upside-down, swirling above jagged rocks, unable to see my oxygen bubbles. During a whiteout, I can float for five minutes with no idea where I am.”

Sloan is awed by the milky nothingness he confronts during urchin spawning season, when the sea teems with delicate, transparent creatures of great beauty. The currents and low visibility make diving too risky. “Imagine if you could see all the pollen spores in the air. It’s like snorkeling in a tub of bathwater after you dropped a bar of soap in it. This is the soup of life, you understand.”

He first dipped a toe into that soup at age 5, during a fishing holiday to the Scottish Highlands. (The family motto: Sleep long and prosper.) When the lure of his older brother, Robbie, got snagged on some slimy seaweed, Roddie volunteered to fetch it. “I must have walked only a few yards, but it seemed like a few miles,” he says. “I remember thinking that the sea is this wonderful place.”

Which, growing up in the land-locked hamlet of Dunscore he never much got to experience. “At 19, I kind of struggled off into life,” he says. “I was bitterly disappointed with it.” He drifted through Europe, finding work in restaurants as a porter, a cook and a manager. At 27, he landed in Oslo and got a job in a sports lounge. While tending bar he met his future wife, Lindis, a college student who had come to watch a British soccer match on the wide­screen TV. She asked him to change the channel. He complied. They’ve been a couple pretty much ever since.

It was Lindis’ brother who suggested that Roddie move to Arctic Norway and hunt the feral urchin. “The big problem was not fishing them,” Roddie says. “The big problem was selling them.” Business was never easy, though Sloan began to source some of the continent’s top restaurants, like Alain Ducasse’s Le Louis XV in Monaco. But when his Paris wholesaler went bust in 2008, he decided to return to school and pursue a degree in engineering. A phone call from René Redzepi changed all that. The Noma chef asked Sloan to ship his greens to Denmark. Sloan was reluctant, but at Lindis’ urging—and after tripling the price as a disincentive—he gave in. “I was ready to throw in the beach towel,” he says. “René saved my career.” Noma now has a standing order for 100 pounds a week.

The greens are at their prime from November to the end of February. When the season winds up, Sloan switches to mahogany clams, which Norwegian fishermen once used as cod bait. The clams stop reproducing after 25 years, and some that Sloan harvests are hundreds of years old. “They’ve spent centuries just lying in their beds,” he says. Bored, not happy as, well...clams. “If a mahogany clam had a brain, it might think, ‘I’ve just turned 350. Why wasn’t I born a dog? Twelve years of this crap and it would all be over.’”

Urchins lack brains, too. The test—its spiny outer shell—protects what is basically an eating and breeding machine. The skeleton is divided into sections running from top to bottom, like the segments of an orange. Inside the body are five corals of roe, sometimes called tongues. On the underside of the test are a muscular system and five self-honing calcium carbonate teeth that allow the urchin to chomp through stone. This chewing apparatus is known as Aristotle’s lantern, from a description in the fourth century B.C. philosopher and naturalist’s Historia Animalium. (Scholars recently proposed that he was actually referring to the test, which resembles the bronze lamps of ancient Greece.)

Urchins are among the earliest forms of life known to have existed. Their fossils date back some 450 million years. “The little buggers are believed to share a distant common ancestor with humans,” says Sloan. Which sounds like the setup for another Norwegian joke.

Around 800 species of urchins are still extant. All have roe that’s edible, though not necessarily palatable. In the kitchen of his farmhouse, Sloan demonstrates how to cut around the Norwegian green’s mouth and scoop out the tongues. In theory, urchins should be opened with a coupe oursin—a tool specially designed for the job. Sloan doesn’t own one, so he uses his wife’s nail scissors. Inserting the tip into the mouthparts, he snips off an itty-bitty piece and trims the top third of the shell to reveal the roe. He spoons out a fillet and places it on your tongue: The sensation is soft and pillowy. “I love the taste of urchin when it’s really good,” Sloan says. “You start with sea salt, then you get a big iodine hit, and, at the end, a distinctive sweetness that sits in your mouth for hours.”

***

Oyster farmers in the United States have lately twisted the term terroir to create “merroir,” which refers to the flavors imparted by different areas of the sea. In the urchin’s case, flavor depends on the species and the seaweed it eats, says John Lawrence, who wrote the book on the subject (it’s for sale: Sea Urchins: Biology and Ecology, $200, Academic Press).

The merroir of oysters varies widely—generally, smaller varieties tend to have a slightly metallic taste. We ask: In the urchins’ briny universe, does size matter? “The urchin gonad is both a nutritive reserve organ and a gametogenic organ,” says Lawrence, a professor at the University of South Florida. “It is a nutrient reserve organ because it produces nutritive phagocytes that store protein and glycogen. These are produced in the gonads during the first part of the reproductive cycle and are transferred to the gametes. The gonads are most flavorful when they consist primarily of nutritive phagocytes and not gametes. It is possible the gonads of small urchins consist primarily of nutritive phagocytes.”

Simply said, Sloan’s finest urchins are much like a juicy cut of Wagyu steak: lots of energy stored. The nutritive phagocytes of the roe and the fat of well-marbled beef account for their robustness. Sloan has an even simpler explanation for why his greens are so exquisite. “By June, when the midnight sun arrives, there’s lots of algae for them to eat,” he says. “Everything grows slowly up here, so the urchins taste better.”

***

Both fragile and destructive, the urchin is a tempest in an environmental seapot. In every corner of the planet, there seem to be either too few or too many. The French and Irish exhausted their resident stocks years ago. In Maine, Nova Scotia and Japan, urchin populations have been drastically reduced by overfishing and disease.

Meanwhile, off the coasts of California and Tasmania, overfishing the animal’s natural predators and large-scale change in ocean circulation—believed to be an effect of climate change—have turned vast stretches of seafloor into “urchin barrens” that remind you of moonscapes. The urchins multiply, chew down the kelp and devastate marine ecosystems. “Management of the sea is the only way,” says Sloan.

He culls his wild urchin beds on a five-year rotation, and wants Norway to adopt a hands-on approach—instituting quotas and establishing fishing zones. In return, a hunter of urchins might produce an underwater map or feed them kelp washed ashore when natural supplies are scarce.

***

From a jetty in Nordskot Harbor, Sloan gazes over the sea, but a gray mist obscures the cliffs and slopes. “I’d like to plant maple trees on my land,” he says, a bit wistfully. A neighbor told him the trees wouldn’t produce sap for at least 25 years: “You’ll be very, very old.” Sloan told the neighbor, “That’s not the point. I’m looking to the future.”

Sloan would be happy if the future looked a lot like the present. “I’ve got a smart woman as a wife and an old, fat Labrador,” he says, laughing at the Norwegian jokiness of it all. “I don’t need a Ferrari. I can’t watch more than one TV. I can’t sleep in more than one bed. If you have enough in life, that’s all that matters. I’m just clearing sand off the bottom of the ocean.”