The Opihi Shellfish Story

What’s going on underneath those shells? From gastronomy to conservation to evolutionary biology, we pry the secrets out of these little limpets.

Opihi with algae camouflage mix with undisguised shells in the Bishop Museum shell collection.

Photo: david croxford

Of all the gastropods in the sea, Hawaii loves the humble opihi best of all. With shells shaped like miniature Mount Fujis, the tenacious way they cling to rocks and a sharp saltiness that complements the mildness of poi so well, opihi are both cultural treasure and coveted pupu.

Big Island opihi picker Brian Calantoc.

Photo: josh fletcher

You will find them in the wild along remote shorelines from the Big Island all the way to Gardner Pinnacle, the last barren outcrop in the Northwestern Hawaiian Islands. You will find them rattling around in bags tied to the waists of opihi pickers, who risk their necks to get them. You will find them next to the poke in Honolulu fish markets, selling for up to $18 per pound in the shell. But as a rule, you won’t find them along any stretch of coast where you can also find a place to park, because where people go, the opihi disappear—often right down the gullet of whoever sees them first.

When it comes to fresh Hawaiian seafood, nothing spends less time in transit than the opihi plucked off the rocks and slurped right out of the shell, wriggling tentacles and all. They are typically eaten raw, either plain or poke style, with limu and a dash of sea salt. They also go well on the grill, seasoned with shoyu and ginger perhaps, or a splash of Tabasco or, in a pinch, a spare packet of Taco Bell hot sauce.

At the haute end of the spectrum, there’s a New Wave Opihi Shooter on the appetizer menu at Alan Wong’s—a single raw opihi in a narrow cordial glass filled with spicy tomato water, fennel, basil and ume shiso essence, all meant to be downed in one gulp. Chef George Mavrothalassitis, of Chef Mavro restaurant, once substituted opihi for abalone in a ceviche. It turned out great, he says, but he admits that he prefers his opihi live and unadorned. “The best way is to go to the rocks, grab some opihi, a baguette, a bottle of white wine, and it’s enough,” he says. He is, of course, French. Most opihi lovers would take a cold Heineken over a glass of wine.


The Price of Opihi—More Money for Fewer Shellfish: Until recently, the market price of opihi has skyrocketed, while the annual harvest has declined.

infographic: kiki karpus, source: hawaii state dlnr

On the palate, opihi are rubbery yet crunchy. They taste like the ocean, only richer, but are an acquired taste. Tourists don’t come to Waikiki with opihi on their must-try list, and that’s just as well, since opihi are already too popular among locals for their own good.

Low tide, calm seas and yellowfoot aplenty — even under these ideal conditions, opihi picking carries risks.

photo: josh fletcher

While the Neighbor Islands still have some healthy opihi habitat, Oahu’s ‘pihi grounds have been hammered so hard for so long by so many  pickers that you’re more likely to find a pair of opihi-shell hoop earrings in a hotel gift shop than you are to find a legally pickable opihi on a rock in Honolulu County. There are efforts afoot to better manage the fishery, but, in the meantime, opihi on Oahu are essentially a shellfish that’s been loved to death.

Hawaii’s Deadliest Catch

If you have ever seen opihi on their home turf, they probably appeared to be stuck in place, like barnacles. Actually, they creep slowly across the rocks as they graze on algae, like so many tiny cows in a field. It’s when opihi are feeding that opihi pickers get their shot at popping them loose with their butter knives or paint scrapers. If the picker blows the first attempt, though, it’s game over. An alarmed opihi clamps down on its rock so tightly not even the most monstrous surf can knock it off. This attachment is sometimes equated with stubborness. The former state legislator James Wakatsuki, Speaker of the House in the 1970s, was nicknamed “The Opihi” because once he took a position on an issue he would not budge, no matter what.


Blackfoot and yellowfoot opihi on the rocks.

photos: elyse butler and matt mallams

The intense opihi-rock connection is also equated with the bond between mother and child, which sheds light on why opihi are in such demand at baby luau, the celebration of a child’s first birthday. Babies and clingy keiki in Hawaii are sometimes called “little opihi,” as in “Mommy’s little opihi needs to let go now so mommy can have her arms back.” Opihi also tend to cluster together with other opihi, which reminds people of tightly knit families, and enhances opihi’s cuteness a lot.

Researcher Chris Bird is unraveling the secrets of opihi DNA, but first he has to pick them.

This cuteness, however, belies a dark side. Opihi are deadly. The Hawaiian saying, He ia make ka opihi, the opihi is the fish of death, sums it up well. It’s not because of anything opihi do, it’s because of where they live, along dangerous shores. A state Department of Health review of drowning deaths from 1993 through 1997 found nine people drowned while picking opihi. Between 1999 and 2009, on the Big Island alone, at least 13 opihi pickers died in drownings, falls from cliffs or, in one case, after getting stuffed into a blowhole by waves, according to news stories in the Hilo Tribune-Herald. With grim numbers like these, opihi are deadlier than sharks, box jellyfish or any other creature living in Hawaiian waters.

Brian Calantoc of Hilo is one of a handful of people on the Big Island, where most of the opihi sold in Honolulu come from, who pick opihi for a living. He spends several days a week working opihi spots around the island. He pays $50 a year for a commercial fishing license so he can sell his catch to markets, and he takes orders through word-of-mouth contacts and via Craigslist, where he currently charges $200 for a one-gallon mayo jar of opihi, cleaned and shelled.


Guy Tamashiro of Tamashiro Market sees demand for the pricey shellfish fall in tough economic times, while supply increases as more pickers pound the rocks for cash.

photos: elyse butler and matt mallams

Calantoc is well aware of the dangers of his trade. He knows pickers who have drowned, and he’s been in some scary situations himself. “I’ve had waves knock me off into the water before,” he says. “It’s spooky getting swept into the ocean.” The key to survival is not to panic if you get washed off the rocks, he says, and to try to minimize the risk of that happening in the first place. “I don’t go when there’s stupid crazy lightning and thunder and 10- to 15-foot waves,” he says. “You gotta know your limits.”

The Opihi  as Snail

Opihi are limpets, part of a broad category of marine snail characterized by conical shells. Limpets like opihi have gills, a powerful suction-cup-like “foot,” something resembling a heart, and a mouth at the end of a protractible mouth tube. They don’t have actual eyes, but they do have eyespots, which are sensitive to sunlight and shadows. Their little worlds are dominated by darkness and light. If the shadow of an opihi picker falls on one, it clamps down with all its might and the picker may as well move on to the next rock.

Limpets are found around the planet, but the three species of Hawaiian limpet are endemic, meaning they’re found nowhere but Hawaii, unless a Hawaiian food lover arranges for their travel. The most common opihi is the blackfoot, or opihi makaiauli, which lives on the wet rocks above the brunt of the surf. The kneecap opihi, also known as the koele, lives underwater from the low-tide line down to 10 feet. The yellowfoot, or opihi alinalina, lives in between, where the rocks get pounded hardest by waves. The yellowfoot is preferred by opihi aficionados. The blackfoot, which are the easiest to pick, are called “the lazy man’s opihi.” The kneecap grows the largest, getting up to four inches across, which is actually more like a knee pad.

It is widely believed that a fourth species of opihi can be found mainly in the Northwestern Hawaiian Islands, with a thicker and pointier shell than the others, but opihi science has learned otherwise. “There is no fourth species,” says Chris Bird, a biologist who has been unraveling the mysteries of the opihi genome in his Coconut Island laboratory at the Hawaii Institute of Marine Biology. In a soon-to-be-published paper, Bird reports that, while this so-called fourth species looks different from the other species, it is genetically identical to the opihi makaiauli and the opihi alinalina. In other words, it’s the blackfoot and the yellowfoot in disguise. “What we’ve thought was a fourth species doesn’t really exist,” says Bird. “We need to take it off the books.”


Guy Tamashiro of Tamashiro Market.

photos: elyse butler and matt mallams

Loved to Death

In the state Legislature, opihi have a friend in Sen. Clayton Hee, an advocate for Native Hawaiian cultural issues, including making sure there’s enough opihi in the ocean for families who want to pick them for their baby luau. Hee enjoys eating opihi himself, but not so much that he would strip every last limpet from the rocks. “The mentality now is, ‘Take ’em all, cuz if I don’t take ’em the next guy going take ‘em,’” Hee says. “We need to shift our thinking back to conservation for future generations.”

Every year for the past six years, Hee has introduced legislation that would toughen restrictions on opihi picking. Currently there are just two rules: a size limit (1.25 inches with shell, or .5 inches without shell), and the requirement that commercial opihi pickers have commercial fishing licenses. Hee’s latest measure would set bag limits, establish seasonal closures on the Neighbor Islands, and place a five-year moratorium on opihi harvesting on Oahu to give the island’s opihi stocks time to recharge.

Hee is amused when someone suggests that he has shown opihi-like determination in keeping the issue on the legislative agenda, but he does not wish to be compared to James “The Opihi” Wakatsuki. “Maybe I’m already an opihi,” he says, “but I hope I can be a little more flexible than that.”

The closest Hee has gotten to easing pressure on opihi through the law came in 2006, when his first opihi bill, which imposed an outright ban on the commercial sale of opihi, made it all the way to Gov. Linda Lingle’s desk. She stamped it with a veto, declaring it would create an opihi black market and that no analysis had been done to show that a ban was needed. The following year, the Nature Conservancy of Hawaii launched an initiative called The Opihi Partnership, which has brought together Hawaiian cultural practitioners, scientists, government agencies and other stakeholders to share information and gather baseline data on opihi populations at sites around the Hawaiian Islands. It’s an ongoing effort that’s basically counting opihi to monitor how they’re doing over time.

Meanwhile, although nobody denies that Oahu is an opihi wasteland, the health of Neighbor Island populations remains subject to debate. Tamashiro Market’s seafood manager, Guy Tamashiro, points to the opihi in his own fish freezer as evidence that opihi stocks on the Big Island, where his three suppliers reside, are doing just fine. “I pretty much have opihi 98 percent of the year,” he says. “The only time I don’t is when I screw up and don’t order enough. It’s not in short supply.”


They gave their lives for science—dried opihi in the UH lab of Harry Ako, who says commercially viable opihi farming is five years away.

photos: elyse butler and matt mallams

If there’s an opihi problem, Tamashiro says, it’s with people who try to sell opihi without a license. Every year, he says, he gets dozens of phone calls that go like this:

“Eh, you like buy opihi?” the callers ask.

“You get commercial fishing license?” Tamashiro says.

“Nope,” they say.

“I cannot buy if you don’t have commercial fishing license,” he says.

 “Oh,” they say. “So you like buy opihi?"

Down on the Opihi Farm

Because of their ability to transform algae directly into protein, and because of a growth rate that takes them from free floating larvae to full-grown limpet in just a few months, opihi have great aquaculture potential, which could someday relieve pressure on the wild population. Researchers have worked on the issue since the 1970s, but the closest supermarkets have gotten to carrying farm-raised opihi came in the 1990s, when Dale Sarver, a Ph.D. marine ecologist and aquacultural entrepreneur, spawned and raised opihi in Kona. Although he demonstrated that it’s technically possible, he couldn’t make it profitable. “It was so labor intensive we were making only about eight cents apiece off the opihi,” he says.

The advancement of opihi aquaculture is currently centered in the biochemistry lab of Harry Ako at the University of Hawaii at Manoa. One of the big questions Ako has looked at is what to feed opihi. Their favorite food is the brown scuzz that grows naturally inside of a seawater tank left in the sun, Ako says. But commercial opihi farmers will want a more reliable feed source than brown scuzz that just appears all by itself. Ako tested a variety of marine protein meals and soy meals on the opihi in his lab, and the opihi weren’t crazy about any of them. Then Ako put double-stick tape on some nori, the dried sheets of seaweed used for sushi, stuck it on the opihi tank wall, and—Eureka!


Harry Ako from UH Manoa.

photos: elyse butler and matt mallams

“Opihi love nori,” Ako says. “That was a breakthrough.”

Ako’s next step is to get his test subjects to spawn. Overall, he thinks commercially viable opihi farming is about five years away.

Farming is not the only potential way of relieving pressure on wild stocks while still meeting consumer demand. There’s also the Irish alternative.

In 2003, a Kauai surfer named Patrick Murphy was in Ireland on a combination journey-of-discovery-to-the-family-homeland and surf safari. He paddled out at high tide to surf a point break in County Kerry, surfed for several hours as the extreme tide dropped several feet, then walked back in over the bare reef, where he discovered the biggest opihi he had ever seen.

OK, strictly speaking, they weren’t opihi. They were North Atlantic limpets, opihi’s Celtic cousins. You might think of them as the Irish Opihi. In any case, Murphy swears they taste just like primo Hawaiian yellowfoot. Fast forward to the present, and Murphy now lives in a beach town in Scotland, where he runs a Web-based limpet export business, the Emerald Island Opihi Co. He hasn’t exactly been swamped with orders from Hawaii, though. “Almost all of my sales have been to Hawaiians who’ve moved to the Mainland,” he says.

Murphy has no competition among other pickers, since the Scottish do not care for limpets, and the Irish, who were forced to eat them during the Great Famine, flat out hate them. “I’ve gotten some strange looks,” he says.

Origin of a Species

According to recently published research by Chris Bird, the biologist who’s been decoding opihi DNA, opihi’s closest relatives are actually Asian.

Imagine a Japanese rock covered with limpets and entangled in the roots of a fallen tree adrift at sea. Imagine that tree washing up on a black sand beach on Kauai, 5 million years ago, when Kauai was young and had black sand beaches. Nobody knows how the first limpets came to Hawaii, but that’s one possible scenario. Bird has shown that all three species of Hawaiian opihi descended from Japanese limpets that colonized the archipelago between 3.4 million and 7.2 million years ago.

This finding has made a splash in the world of evolutionary biology because it’s the first time that “adaptive radiation,” where multiple species evolve from a single ancestral species, has been seen in Hawaiian waters. The conventional thinking has been that Hawaii was an end-of-the-evolutionary-line for marine organisms. Each ancestral fish, mollusk, algae or whatnot that somehow found its way to Hawaii and evolved into a new species stopped there. Bird’s opihi research has shown this isn’t so, that one aquatic species can become many, and Hawaiian waters are not an evolutionary dead end.

What does this mean for the average, everyday opihi lover?

 “The average, everyday opihi lover already knew opihi were special,” Bird says. “This is not going to change the way they taste or how much people want to eat them. It’s just adding new information that makes them a little bit more of a Hawaiian treasure than they already are.”

Fast Facts:

Opihi spend their larval youths floating freely in the ocean. They can survive as larvae for as long as 18 days, but after two days or so they start looking for a rock to settle on. Researchers at the Hawaii Institute of Marine Biology have determined that the larvae do travel interisland. Each island has its own opihi population.

David Thompson is a freelance journalist who has written for HONOLULU on subjects ranging from donkeys to vog to dining tours.