It's nearly midnight, and Oscar Robinson Sr. has been on his feet for hours, stitching a torn fishing net by the light of a naked bulb. At sundown, two Steller sea lions—one of them a bull, which typically weighs over a ton—punched straight through the mesh and popped up behind the fishing crew's aluminum punt with a bad-tempered gasp.

Now Robinson must mend the net—"the bag," as he calls it—in time to fish the next outflowing tide, which turns at 4:30 a.m.

He works patiently: If it isn't one thing, it's another. Today it was sea lions, tomorrow it might be the current's raw power snapping the net anchor poles or a grizzly bear stalking the camp.

This is the last great eulachon fishery on Earth, near the mouth of the Nass River in British Columbia, just at the tip of the Alaska Panhandle. Eulachon are a species of smelt, each fish a bolt of silver-blue not much longer than a ballpoint pen.

Along the river's banks, you can still hear eulachon spoken of as saak, their name in the language of the Nisga'a, one of the indigenous peoples known in Canada as First Nations and in the U.S. as Native Americans.

But the fish are also known as halimotkw, often translated as "savior fish" or "salvation fish." Eulachon return to the rivers here to spawn at the end of the North Pacific winter, when historically food supplies would be running low. In lean years the eulachon's arrival meant the difference between life and death for people up and down the coast.

Today, the fish that used to safeguard native people from starvation is itself in need of a lifeline.

Eulachon was once such a valuable commodity that trade routes in coastal British Columbia and southeast Alaska came to be known as "grease trails." The eulachon's buttery flesh is so rich in oil that a dried fish will light and burn like a candle. Aboriginal cultures developed a process to extract that fish oil to create a vitamin-rich grease that resembles vegetable shortening—though with a malty, fishy flavor that is, famously, an acquired taste—and that could be transported or stored without spoiling.

NG STAFFSOURCES: INTERNATIONAL UNION FOR CONSERVATION OF NATURE; NOAA; DEPARTMENT OF FISHERIES AND OCEANS CANADA

It was a grease trail that led Alexander Mackenzie down to the sea near Bella Coola in 1793, when he became the first European to reach the Pacific Ocean by land along a northern route, more than a decade ahead of Lewis and Clark. Many of the pathways went on to become pioneer roads and modern highways.

But in the 1990s, the silver runs of eulachon began to collapse. Theories to explain the decline ranged from overfishing to climate change to the industrialization of river corridors. Since eulachon had never been an important species to commercial fisheries, little research was done to determine the cause. Now, more than two decades later, many eulachon runs live on only in memory.

New threats to the species, such as coastal pipelines and port expansions, continue to arise, but there are also signs that a fragile recovery could be under way. If so, the eulachon's saviors will be the same indigenous tribes that the fish once sustained.

A Sudden Vanishing Act

Eulachon were first documented by Meriwether Lewis in 1806, when he noted in his journal that the little fish were "taken in great quantities in the Columbia River." He even described how he liked to prepare them:

I find them best when cooked in Indian style, which is by roasting a number of them together on a wooden spit without any previous preparation whatever. They are so fat they require no additional sauce, and I think them superior to any fish I ever tasted.

In those days, immense eulachon spawning runs took place as far south as the Mad River in northern California and all the way up the coast to southern Alaska. The lower Columbia, which marks the border between Washington and Oregon, was one of the greatest eulachon rivers of all. Some scholars argue that the word "Oregon" is derived from a pronunciation of the word "eulachon" used by aboriginal traders as they told European explorers of the riches to be found in the West.

View Images A Nisga'a woman hangs eulachon on a ganee'e, or air-drying rack. Photograph by Paul Colangelo

The Cowlitz Indian Tribe has fished eulachon on the Cowlitz River, which flows into the Columbia, for centuries. But in 1993, the fish failed to return to the Cowlitz. And in the Columbia River, the yearly catch had dropped by a staggering 98 percent from the historical average.

This vanishing act did not immediately set off alarm bells. Eulachon are mysterious, in some years spawning in incredible numbers and in others—1984, 1964, 1907, 1890—hardly showing up at all. But when the fish known locally as the Columbia river smelt failed to bounce back in the years that followed, the Cowlitz and other coastal indigenous nations were the first to start asking questions.

For the Cowlitz, who take their name from the local Salish word for eulachon, the disappearance threatened their cultural identity. "We were very distressed," says William Iyall, chairman of the tribe. The decline, he says, "wasn't recognized by anybody else."

Eulachon crashed first in the southern reaches of their range, but over the past 20 years, every run south of the Nass River has suffered severe declines or—as in rivers ranging from the Klamath in California to the Kemano, just 100 miles (160 kilometers) south of the Nass—almost disappeared.

View Images Nisga'a fishing camps line Fishery Bay on the Nass River, home of the world's last great eulachon run. Photograph by Paul Colangelo

Megan Moody, who'd grown up catching eulachon in the Bella Coola River on British Columbia's central coast as a member of Nuxalk First Nation, began investigating the problem as a graduate student in fisheries science. Her first discovery: how little was known about a fish that some Pacific coast indigenous people value even more than salmon.

"It all comes down to economics," says Moody, who's now the stewardship director for the Nuxalk. "In the mainstream world, if it's not a commercial commodity—a highly valued species in the fishery management world—nobody pays attention to it."

But among First Nations on the British Columbian coast, eulachon grease has long been a beloved delicacy.

Creamy as lard when cool and light as olive oil when warmed, the grease is rich in vitamin A and a significant source of vitamins E and K, along with healthful fatty acids. It's potent fuel for the body: A single tablespoon provides more than 125 calories, and just five ounces (150 milliliters)—an amount still commonly eaten by Nisga'a elders today—supply half an adult's recommended daily energy intake.

Talk to men and women raised in grease-making families, and you'll soon hear too of fevers broken or earaches cured with a dose of eulachon oil. The grease is also a notorious laxative and a topical treatment for skin conditions—no surprise, given that eulachon are high in squalene, a chemical found in human skin and used in the production of moisturizers.

View Images Eulachon runs feed hungry wildlife, from eagles to whales. Here Nisga'a fishermen hunt sea lions on the Nass River. Photograph by Paul Colangelo

Theories on the Fish's Decline

Moody's research merged biological science and traditional local knowledge to help develop what is now the leading theory on the eulachon's decline. Such a widespread, closely timed collapse, she says, had to involve changes taking place in the ocean, where eulachon spend more than 95 percent of their lives.

Exactly what those oceanic changes might have been is still debated. Federal fisheries experts in the U.S. and Canada rank climate change among the most likely drivers of the eulachon crisis, but warming oceans can affect species in different ways, leading to, among other things, shifts in food supplies, predators, and currents.

Moody thinks that climate change effects pushed eulachon into a slow decline. And that the ocean shrimp fishery—which was killing large numbers of eulachon as bycatch, fish unintentionally caught while targeting other species—then tipped the stocks into collapse.

This could account for why the coast's biggest rivers, such as the Columbia, Fraser, and Nass, still have eulachon runs—albeit smaller ones than in the past—while lesser rivers have witnessed near total local extinctions. The large eulachon runs in big rivers, the theory goes, could withstand heavy losses to bycatch and still endure; smaller runs could not.

Moody's research proved to be perfectly timed.

In 2007, the Cowlitz Indian Tribe petitioned the U.S. government to protect eulachon in Washington, Oregon, and California under the Endangered Species Act. Her work helped inform the resulting scientific review that led, in 2010, to eulachon being listed as a threatened species in the U.S. south of Alaska.

In Canada, eulachon are now classified as endangered in every river system except the Nass and nearby Skeena River.

View Images By timing their fishing to the outgoing tides, Nisga'a fishermen catch only eulachon that have already spawned. Photograph by Paul Colangelo

Signs of a Comeback

Eulachon are unique among at risk federally listed species in that there may be more eulachon at any given time than the total number of individuals from all other U.S. endangered species combined.

But eulachon are "forage fish," meaning they play a bedrock ecological role as food for almost every predatory creature in the sea. Along Pacific Northwest rivers, people know the eulachon are coming when whales, seals, sea lions, eagles, and tremendous flocks of gulls show up to meet them. Sheer abundance is the eulachons' survival strategy, and no one knows how large the population needs to be to remain viable.

The list of potential hazards to the fish continues to grow.

Shifts in global cargo shipping have sparked major port expansions and dredging projects across the Pacific Northwest, often at or near the mouths of rivers. Plans are also afoot to move far more oil and gas through these terminals, including along such corridors as the Fraser River—British Columbia's largest, which historically had eulachon runs comparable to those of the Columbia—and Kitimat River, where the number of spawning fish has collapsed to fewer than a thousand and where a spill of bitumen (a heavy, molasses-like oil) from the proposed Northern Gateway pipeline could potentially wipe out the eulachon.

Yet there are also indications that the fish's stocks could be on the rebound.

The eulachon are better protected than ever before. Ocean shrimp boats on the Pacific coast have been equipped with mandatory bycatch-reduction devices since 2003, and last fall an experiment with LED lights strung on trawl fishing lines reduced eulachon bycatch by 90 percent, prompting officials to recommend that fishers start using the new technique immediately.

Meanwhile, 335 miles (540 kilometers) of creeks, rivers, and estuaries in the U.S. have been identified as critical eulachon habitat by the National Marine Fisheries Service, and a complete recovery plan is expected in 2016.

In some locations, the fish could be returning as mysteriously as they disappeared. In 2013, Nuxalk people along the Bella Coola River witnessed schools of eulachon arriving—a shock in a place where no one under the age of 20 could remember such a scene. Over the following months, the community prepared to revive the tradition of the eulachon welcoming ceremony, which hadn't been performed in decades.

Last year, hundreds of people sang and danced as a totem pole—representing the myth being Raven in human form, holding a male eulachon in one hand and a female in the other—was raised to face the sea. Alongside the celebration, in the quiet waters, eulachon were once again returning to a river where only a few years before almost none could be found.

Last year's Columbia River run may have been the largest in a quarter century: As many as 330 million fish may have returned to the river.

Two-ton batches of euchalon are cooked for hours, stirred constantly, to release the oil. Eulachon "grease" remains an important food, medicine, and trade item.



Inside the Stink Box

That same season was a hard one on the Nass River. But the Nisga'a fishermen didn't want to imagine that their own run might have taken a turn for the worse.

The river was blocked by ice when the eulachon arrived, they said, and many fish were forced to spawn downriver from Fishery Bay, where the grease-making camps—rustic shacks known by names like Dirty Dozen and Millionaires'—dot the shoreline.

Fisheries biologists agree that there's no need to be concerned about a single year's lower catch. No one, however, can say for sure.

View Images Eulachon ferment in wooden pens before being cooked at this Fishery Bay camp. Phootgraph by Paul Colangelo

Each crew member would be able to take home enough fish to eat fresh, smoked, or air-dried, but none of the camps would completely fill the wooden-walled pen, about the size of a modest living room and lined with hemlock boughs, where the tons of eulachon "ripen" before being made into grease.

Each camp leader had his own idea of how long to let the fish ferment.

Mitch's Camp, led by Nisga'a Nation President Mitch Stevens, made a light, fresh-tasting grease after only five days. The Dirty Dozen camp, headed by Johnny Robinson, an elder with eight decades' experience in Fishery Bay, aged their fish for so long that some of the younger men actually threw up at the smell of them. The Nisga'a call the fermentation pen the "bin," but it's better described by the Nuxalk term: the "stink box."

The aged eulachon are ultimately loaded into what the Nisga'a call pots—huge vats, watertight as wooden boats, that can cook more than two tons of fish at a time. In the past, people used smaller wooden boxes heated with hot rocks; today's pots have a thick steel base that sits above a fire pit or propane burners.

During the cooking, the eulachon oil separates to form a transparent surface layer. Strained into buckets, the grease ranges in color from palest gold to nearly black, depending on how long it's been fermented.

A single round of cooking can be what one grease camper calls "an all-dayer, all-nighter." After so many hours in the reeking steam, many men simply throw their clothes in the garbage.

Still, each spring, as they have for centuries, people from neighboring First Nations such as the Haida, Haisla, Gitxsan, and Tsimshian travel to the Nass, often bringing their own traditional foods—cockles, herring roe, seaweed—to barter for eulachon grease.

Some visitors fly in from faraway places, and deals might be made via Facebook. Trade products include everything from Chinese takeaway to energy drinks to diesel-powered generators; there are whispers of grease being swapped for marijuana. The ancient trade continues, changing with the times.

Step inside a traditional Nisga'a smokehouse.



Back Onto the River

But first comes the hard work of bringing in the catch. At dawn, Oscar Robinson and the Dirty Dozen crew head back out onto the Nass. Spring has arrived, but it's still cold enough that anything wet is quickly glazed with ice, which on an open fishing boat means everything is slick.

The gulls wake up and begin to fill the air, thousands upon thousands of them. "Put your hood up!" shouts Robinson. Too late—the most junior member of the crew gets bombed with a white streak from above, and everyone has a laugh.

"I wonder if a storm's coming?" says Robinson, studying the birds.

"Something's coming," says Colten Wilson, a young man whose leg is still healing from a fall through the winter ice. Then, staring up at the gulls as they soar higher and higher, Wilson's face grows round with awe. "They look like eulachons flying around," he says.

Robinson likes this dreamy image, and smiles. "A big bag of eulachons in the sky."