The tide sets the alarm clock on the Central Coast, not the hour. On the best survey mornings, that means boats leaving the docks at Shearwater before the sky has any real light in it—gear loaded, coffee in hand, the water black and flat. Emma Hancock has gotten used to sending her family photos at 3:00 in the morning.
The destination is a rocky intertidal shoreline exposed only at the lowest tides, the kind of place most people would walk past without a second look. What the team is searching for is Pyropia abbottiae—known to the Heiltsuk as łq'st, and by different names to different nations along the coast—a thin, dark blade that peels off the rocks each spring and has fed communities along this coast for longer than anyone has been keeping written records.
It is also, increasingly, a species at the centre of a coastal mystery.
Pyropia has been a food source around the Pacific Rim for thousands of years. Related species are farmed at industrial scale in Japan and Korea—dried, pressed into sheets, wrapped around rice. On the Central Coast of British Columbia, Heiltsuk harvesters and many other coastal nations have gathered it at traditional sites for generations, drying the blades on rocks and racks in the spring sunshine. The harvest is a family affair. Grandmothers sort the piles. Everyone has a role.
What most people don't know—what scientists are still working out—is that the seaweed harvesters recognize each spring is only half the story.
For much of the year, Pyropia essentially disappears. The visible blades die back and the organism retreats into a microscopic filamentous stage called conchocelis, burrowing into calcium carbonate—barnacle shells, mussel shells, limpet shells—somewhere on the shore. You cannot see it with the naked eye. It bores into the calcium carbonate of shells and barnacles, invisible from the outside.
"The conchocelis is a bit of a needle in a haystack," says Hancock, an MSc student in Patrick Martone's lab at UBC who now leads much of the current field monitoring work. Detecting it requires extracting DNA from shell samples and searching for a genetic signal unique to a single species among the roughly dozen or more that share the same coastline.
This hidden stage is not just a curiosity of biology. It may be the key to understanding what happened in 2016.
That year, harvesters across the Central Coast arrived at traditional sites to find almost nothing. Pyropia—present for centuries, woven into the food traditions of coastal nations—had largely vanished.
"No one was expecting that Pyropia would be gone suddenly," says UBC phycologist Patrick Martone, who had been monitoring intertidal communities on Calvert Island when the decline appeared in the data. "And of course, panic sets in, because you think, is it ever going to come back?"
The culprit appeared to be the marine heatwave researchers called the Blob—an anomalous mass of warm water that sat off the coast for an extended period and disrupted ecosystems up and down the Northeast Pacific. Early thinking pointed to hot summer temperatures, or to nutrient-depleted water failing to support growth.
But the story turned out to be stranger and more specific than that.
The very next year, Pyropia came back in one of the strongest seasons researchers had seen in years. That recovery said something important: the population hadn't been killed. Something had simply prevented the blades from forming.
The leading hypothesis now points not to warm summers, but to warm winters. The conchocelis stage appears to need a cold temperature cue before it will release the spores that grow into blades. Miss that cue—because the water never got cold enough—and spring arrives with bare rock where seaweed should be.
"A lot of us think about those really hot summers when the shoreline gets baking hot," Martone says. "But it's the warm winters in this case that I think might have been the culprit."
For Martone, the episode is a reminder of how climate change delivers its surprises. Kelp forest decline is visible, predictable, the subject of well-funded research and public attention. Pyropia's vulnerability operated through a hidden mechanism that nobody saw coming—a cold cue that never arrived, a bloom that simply didn't happen. "I think we're going to have lots more surprises like this in the future," he says.
9 years on from the Blob, the work has entered what Martone describes as a reinvigoration. Hancock is revisiting earlier datasets while expanding surveys north from Calvert Island into Heiltsuk territory, now based out of Bella Bella. The team travels with Heiltsuk Guardian Watchmen from the Heiltsuk Integrated Resource Management Department, reaching traditional harvest sites by boat in the early hours. The intertidal is one of the harshest environments on earth for life, and one of the most punishing for the people trying to study it. The rocks are boulder-strewn and uneven, and Pyropia can be extraordinarily slippery underfoot. Every step requires attention as researchers work their way across the seaweed-covered shoreline collecting measurements and observations. All of it happens against the clock. The tide doesn’t wait, and every survey is a race to complete the transects before the water rises and the site disappears again. The surveys measure harvestable biomass, patchiness, and shifts in distribution across the intertidal zone. Oyster plates have been placed at sites to try to capture the settlement of the conchocelis stage for the first time in the wild.
The Guardian Watchmen are not simply logistical support. Their knowledge shapes the work at every level—from navigating shore landings on exposed coastline to identifying the correct species in the field. Among the roughly dozen or more Pyropia species found along the coast as a whole, Heiltsuk harvesters want only one. Their ability to distinguish it by eye, developed over lifetimes of harvesting, is something no amount of laboratory training replicates. One of the Watchmen, Walter Campbell, looked at survey sites chosen the previous season and was direct: we wouldn't harvest here. The project shifted accordingly.
That collaboration has also revealed something Hancock didn't fully anticipate—how deeply embedded Pyropia remains in community life. Seaweed laid out to dry after a harvest. Families working through the piles together. A grandmother spotting the wrong species by sight and picking it out immediately.
"It definitely is a community binder," she says.
Martone finds something quietly remarkable in the cultural specificity of what harvesters are looking for. Around 20 species of Pyropia occur along the Northeast Pacific coast. Virtually every Indigenous community that harvests the seaweed has settled on the same one.
"I find it fascinating that there's actually quite a bit of diversity out there, but there's something about the deep traditions of collecting this seaweed that just goes across all boundaries," he says. "Is it because it's more nutritious? Is it because it tastes the best? I just find it fascinating that they've all come to the same conclusion."
Hancock now believes the cultural importance of black seaweed on this coast has been substantially underestimated, overshadowed by the more dramatic story of kelp forest decline. Interest is beginning to shift—at the Pacific Seaweed Summit in early May, she saw more people asking questions about Pyropia than she had expected. Heiltsuk Climate Action is focused on food sovereignty and ensuring the traditional harvest persists. A biobanking project run with North Island College is building a genetic reserve against another catastrophic year. Other nations are beginning to explore commercial cultivation—a thread that researchers are careful to keep separate from the more immediate questions of stewardship and food security.
All of it depends on better understanding a species whose most critical life stage has never been directly observed in the wild.
The surveys continue. Samples come back to the lab. The data builds, season by season, toward something that might eventually let researchers anticipate a poor harvest year before it arrives—or support a population showing signs of stress before harvesters reach bare rock.
"If we're looking at winter temperatures one year and they're really warm, we might be able to say—we're worried about the seaweed," Hancock says. "And preemptively take some mitigation steps."
That future is still being built, one low tide at a time. The most critical stage of this seaweed's life remains out of sight, inside a shell, waiting for a cold winter that may or may not come.
