The Last Wild Atlantic Salmon: The Salmon of Knowledge and an Ancestral Food in Crisis

Salmon is one of the oldest foods of the North Atlantic. For thousands of years, it fed the peoples living along the great arc that runs from Scandinavia through Scotland, Ireland, and Britain, across to Iceland, the Canadian Maritimes, and New England. It came back to the same rivers every year, at the same time, in numbers our ancestors could count on, and it was rich enough to carry a family through a winter.

That fish is nearly gone. Right now, in the long light of July, the summer runs should be at their peak, the rivers full of silver fish climbing home to spawn. For most of our rivers, that no longer happens. Across the North Atlantic, wild salmon have fallen from around seven million returning fish in the early 1970s to roughly two million today. No country now permits a commercial catch, and almost every salmon sold in a shop was raised in a pen. The great summer return, one of the surest rhythms of life on these coasts for ten thousand years, is the thing now missing from the water every year. This is the story of what that fish has been to us, why its loss matters more to the peoples of these coasts than to anyone else, and what we can do about it.

The Salmon of Knowledge

To our Celtic ancestors, the salmon was the keeper of wisdom.

The old Irish story tells of a salmon in a pool of the River Boyne. Around the nearby Well of Wisdom stood nine sacred hazel trees, and their nuts fell into the water. The salmon ate them, and took in all the knowledge in the world. This was An Bradán Feasa (on BRAH-dawn FASS-ah), the Salmon of Knowledge.

A poet named Finegas spent seven years trying to catch it, because whoever ate the fish would receive its wisdom. When he finally landed it, he gave it to his young apprentice, Fionn mac Cumhaill (FIN mac COOL), to cook, with strict instructions not to taste it. As Fionn turned the fish, hot oil splashed his thumb. He put the burn in his mouth without thinking, and the wisdom passed into him instead. For the rest of his life, Fionn had only to bite his thumb to know what he needed to know.

This is folklore, not history, and I hold it as folklore. But folklore records what a people valued. Of all the foods our ancestors had, they chose the salmon to carry the wisdom of the world, rather than the deer or the cattle or the grain. They chose the fish that vanished into the ocean, came back to the same river at the same time each year, and fed everyone when it arrived. The salmon was one of the things that made life on these coasts possible, and they honored it accordingly.

Older Than Ireland: Salmon in the Ice Age

Our relationship with this fish is far older than Ireland or Scotland, and to see how old, we have to go back to the last ice age.

Around twenty-six thousand years ago, the world entered the coldest stretch of the ice age. Ice more than a mile thick in places covered Scandinavia, Scotland, Ireland, and the northern half of Britain. Plants, animals, and people moved south into the warmer country of southwest France and Spain and stayed there for thousands of years. Britain was semi-settled before the cold came, but emptied during the ice age.

The salmon moved south as well, into two refuges. Genetic research has traced both. One was in the rivers of northern Spain, where DNA taken from salmon bones between sixteen and forty thousand years old shows the fish lived there continuously through the worst of the cold. The second went south where the English Channel is today. With so much water locked up as ice, the sea was roughly four hundred feet lower, and the Channel was not a sea but dry land with a great river running across it. That river, fed by the Thames, the Rhine, and the Seine, carried southwest into the Atlantic past Brittany. A deep trench off the Brittany coast, the Hurd Deep, is what remains of it now. Salmon of these two refuges had already separated from one another long before the ice reached its greatest extent.

So through the ice age, the salmon and our ancestors lived in the same corner of Europe, in the same river valleys, at the same time. And our ancestors left proof that they knew this fish well. In a rock shelter at Les Eyzies in the Dordogne, on the bank of the River Vézère, there is a life-size Atlantic salmon carved into the stone ceiling. It is just over a metre long; it was made roughly twenty-five thousand years ago while the ice still stood at its greatest reach, and it is one of the oldest images of a fish found anywhere in the world. The salmon is carved as a male, with the hooked jaw and worn look of a fish at the end of spawning. That is not a fish from the sea. That is a salmon upriver in autumn, after the climb home. Whoever carved it had stood on that bank and watched the run.

Then the ice melted, the rivers opened, and both moved north together. Salmon from the Channel refuge spread first into southern England. Salmon from the Spanish refuge travelled further, into southwest England and across to Ireland, and it is the Spanish line that came to dominate in the north. The people followed the fish: to Gough's Cave in southwest England around fourteen thousand seven hundred years ago, to Howburn Farm in Scotland around fourteen thousand, to Ireland's first firm settlement at Mount Sandel on the River Bann around ten thousand years ago. What the people at Mount Sandel ate is recorded in what they left behind: salmon caught in the summer runs, hazelnuts gathered in autumn, wild boar hunted through winter.

The oldest known home in Ireland stood beside a salmon river and lived on the run.

One detail closes the circle. When researchers built a family tree of these rivers from their salmon's DNA, the River Boyne did not group with its neighbours. It grouped with the rivers of northern Spain. The salmon of the Boyne, the river of the Salmon of Knowledge, descend largely from the fish that waited out the ice age in the south, near where our ancestors carved salmon into stone.

Wild Atlantic Salmon Loss Falls Harder on Us

There is a reason the emptying of these rivers costs the peoples of these coasts more than it would cost someone whose ancestors farmed grain in the south. It is not mystical. It is ordinary biology.

The long-chain fats in salmon, EPA and DHA, are the ones the brain and nervous system are built from. The body can also make them itself, from a simpler fat found in plants, but only by converting it, and some people inherit a far better ability to do that conversion than others.

Researchers have traced how that ability shifted across European history, using DNA from ancient remains alongside DNA from people alive today. Before farming, northern hunter-gatherers ate their fats ready-made from fish and had little need to build them from plants. After farming arrived in the south, people living on grain came under strong pressure to convert plant fats well, and evolved the inherited ability to do so. That adaptation is strongest in the south of Europe and grows weaker moving north. It is weakest of all in the far north, because those peoples went on eating fish and never had to develop the workaround.

The likely reason is the simplest one. Our ancestors on these coasts were fed marine fat, ready-made, for ten thousand years, so their bodies never came to rely on making it from plants. This is a pattern across whole populations rather than a diagnosis for any one person, and no study has yet shown that people of Celtic descent are short of these fats because of it. But it means the loss of this fish is not only a conservation story. On average, our lineage is more reliant on taking these fats straight from the water, and less equipped to make them up from a plant-based plate, than people whose ancestors ate from the field. The food shaped the people, and one of the things it shaped was a certain dependence on the food itself.

What Wild Atlantic Salmon Gives the Body

The nourishment in wild salmon is why it mattered so much, and it is worth being specific.

• Omega-3 fatty acids. Wild salmon is among the best food sources of EPA and DHA, the long-chain fats that form part of the physical structure of the brain. Research links them to memory, to the making of the chemical messengers between nerve cells, and to clear thinking into older age.

• Vitamin D. A serving gives more than half a day's requirement, which mattered enormously on coasts where winter light is too weak for the skin to make its own.

• Vitamin B12 and selenium. A four-ounce serving gives well over a full day's B12 and around three-quarters of a day's selenium, supporting the nerves, the blood, and the body's own antioxidant defences.

• Complete protein. About twenty grams per hundred grams, carrying all the amino acids the body cannot make for itself.

• Astaxanthin. The natural pigment that colours wild flesh deep coral, and an antioxidant able to reach the brain. Wild salmon carries far more of it than farmed salmon, which is dyed with a synthetic version added to the feed.

The fish our ancestors called wisdom does, in a plain and literal way, help build and feed the organ we think with.

From Full Rivers to Empty Ones

The wild runs that fed our ancestors for ten thousand years have failed within a single human lifetime.

River or country	Then	Now
Ireland	1.76 million returning (1975)	171,700 (2022)
Maine's Penobscot	75,000 to 100,000 a year	around 1,000 to 1,500
Scotland's River Tay	40,000 by nets alone (late 1980s)	a few thousand to rod, almost all released
Norway	over a million returning	lowest return ever recorded (2024)

Ireland has closed most of its salmon rivers to fishing. Norway shut thirty-three rivers mid-season in 2024. Maine allows no catch at all. The causes are layered: warming seas, damaged rivers, dams, pollution, and salmon farming.

Farming is the part I find hardest to set aside. Farmed Atlantic salmon is a different fish from the one that shaped us. Its feed has shifted toward plant oils, roughly halving its omega-3 content over a decade, and its colour is dyed in. But the deeper harm is to the wild. There are now around 420 million farmed salmon in the North Atlantic against roughly two million wild ones. Farmed fish escape and breed with wild salmon, passing on genes bred for the cage rather than the river, and this genetic contamination has been found in well over half the rivers surveyed across the North Atlantic. The body that oversees wild Atlantic salmon now regards it as the single most serious threat the species faces, because unlike a polluted river it cannot be undone. Sea lice bred in the crowded pens add further deaths among young wild salmon heading out to sea.

What to Eat Now

Wild Atlantic salmon is no longer on the table, so the honest question is what carries what the salmon carried.

The first answer is wild Pacific salmon: sockeye, coho, king. A different but closely related fish, and the only wild salmon left on the market. Alaska protects it well, managing its fisheries for the long term and banning fish farming outright, so Alaskan salmon is spared the escapees and lice that emptied the Atlantic. The honest catch is that it is expensive and not always easy to find, which is why the rest of this list matters.

One principle governs the rest: no land food replaces a sea fish. The long-chain fats are made by ocean algae and travel up the sea's food chain. Grass-fed beef, liver, and pastured eggs are good foods, and they cannot do this job. The answer to a fish is other fish, and the shellfish of the shore. The best of them, on both sides of the arc:

• Herring. The direct heir, carrying even more omega-3 than salmon, along with plenty of vitamin B12 and selenium. Cheap, traditional, and the fish that fed these coasts for centuries. Choose North Sea or Irish Sea herring, which have healthy stocks and are well managed.

• Sardines and pilchards. The cheapest answer of all, rich in omega-3, high in B12, and, because they are eaten whole with the bones, a source of calcium salmon does not have.

• Mussels. High in omega-3, B12, and iron. Rope-grown mussels are among the lowest-impact animal foods on earth, and as native to these shores as food gets.

• Oysters. Less omega-3, but the richest food there is in B12 and zinc.

• Cod liver oil. The traditional winter answer of the North Atlantic, and the one everyday source that properly replaces salmon's vitamin D as well as its omega-3.

The same foods sit on both shores. In New England, the herring is the same species, the sea scallops are well managed, and the flats hold oysters, quahogs, and clams, the same shore food our ancestors gathered in Galway and on Islay, arrived at on a colder coast.

Bringing the Wild Atlantic Salmon Home

Every food above is a patch. A good patch, and I am glad the arc left us so many other foods, but I would rather have the fish back, and that is possible.

In July 2026, the Sustainable Water Network, an umbrella of twenty-five of Ireland's environmental organizations, launched a campaign calling on the Irish government to phase out open-net salmon farming, because it cannot be conducted sustainably and puts Ireland at risk of breaching European water and marine law. Evidence given to an Oireachtas committee this year put the toll starkly: peer-reviewed work shows an average of nearly one returning adult salmon in five lost to the effects of aquaculture in the affected bays, at the very last stretch of a journey across the ocean and home.

I have signed their petition, and it takes a minute. It asks for one thing: an end to open-net salmon farming in Irish waters. If any of this has landed, that is the most useful minute available. The petition is here: https://swanireland.ie/take-action/ban-open-net-fish-farms/.

The Rivers Can Run Silver Again

The druids put all the world's knowledge inside a salmon. Research finds a fish that helped build the brain and body of the people who ate it for ten thousand years, and that those people came to depend on. Two different observations, arrived at in completely different ways, pointing the same direction. Our ancestors knew what this fish did for them. They told it as a story rather than a study, and the story kept the knowledge safe for a very long time.

The rivers of the Wild Atlantic can run silver again. Not quickly, and not without decisions made far above the level of a shopping basket. But salmon is a patient, returning creature, and it has come back from less than this. Meanwhile the choice in front of me is small and ordinary, made at the freezer case, and I make it the same way every time. Wild over farmed.

This is not wellness as a trend. It is wellness as remembrance.

Julie Wardwell, Clinical Ayurvedic Practitioner

References

The Salmon of Knowledge: Macgnímartha Finn (The Boyhood Deeds of Fionn), 12th c., trans. Kuno Meyer, Ériu 1 (1904). The well and nine hazels come from the Dindshenchas of the Boyne.

Ice age refuges and the carving: Consuegra et al., Molecular Ecology (2002); Finnegan et al., Heredity (2013), on the two refuges, the Channel River, and the Boyne's Iberian signature; Musée national de Préhistoire, Les Eyzies, on the Abri du Poisson.

Post-glacial settlement: Gough's Cave, Quaternary Science Reviews (2009); Dowd and Carden, Quaternary Science Reviews (2016); Bayliss and Woodman on Mount Sandel (2009).

Inherited fat conversion (FADS genes): Ye et al., Nature Ecology & Evolution (2017); Buckley et al., Molecular Biology and Evolution (2017); Mathieson and Mathieson, Molecular Biology and Evolution (2018).

Nutrition: USDA Food Data Central; Sprague et al., Scientific Reports (2016), on farmed salmon omega-3.

Decline and farming: Inland Fisheries Ireland; NASCO, State of North Atlantic Salmon and aquaculture policy brief (2025); Norwegian Scientific Advisory Committee (2025); NOAA Fisheries.

Sustainable choices: Marine Stewardship Council and Marine Conservation Society Good Fish Guide (2026); Alaska Dept. of Fish and Game; Gulf of Maine Research Institute and Maine Sea Grant seafood guides.

Taking action: Sustainable Water Network (SWAN), aquaculture campaign and petition, July 2026, swanireland.ie/take-action/ban-open-net-fish-farms; Salmon Watch Ireland, evidence to the Oireachtas Committee on Fisheries, 2026.