The Atlantic Salmon Myth: Does Farming More Make It More Endangered? | Book Recommendation

Foodthink Says

The Atlantic salmon is a creature of paradox. On the one hand, it has become one of the rarest inhabitants of the ocean: few among us are fortunate enough to encounter it (or even taste it). Yet, aquaculture has simultaneously made it one of the most ubiquitous animals in the world. In just a few decades, fish farming has transformed this once-exclusive delicacy, savoured by only a privileged few, into a global commodity and the most widely traded fish on the planet. Perhaps, ten millennia after humanity domesticated cattle, pigs, and sheep, we have led this fish down the very same path: through intensive farming, the species thrives in captivity (within submerged sea cages) while vanishing in the wild. Nevertheless, the fate of wild Atlantic salmon demands our attention. This fish stands as an unparalleled natural indicator of our planet’s health. It possesses the remarkable ability to transition independently from freshwater to marine environments, and then back again. This means that, throughout its life cycle, it journeys from inland rivers to the ocean, only to return to its natal streams. Through the salmon, we can observe the cumulative impact of a host of human activities (from deforestation and dam construction to pollution, overfishing, and climate change) on the natural world. The sharp decline of this species sounds an alarm bell for the transformations underway on land and sea. If we wish to save the salmon, we must halt our destruction of the planet—it really is that simple.

The salmon is an elusive creature, and its life cycle is nothing short of miraculous. A single female will lay around 8,000 eggs among the river gravels, after which males compete to fertilise them. Eight weeks later, the alevins hatch from the golden eggs, relying on the nutrients stored in their yolk sacs for the following 30 days. Once they develop from alevins into fry, they leave the gravel-bedded shallows to venture into deeper, more perilous waters. In these deeper reaches, a salmon must survive for up to three years, finding sufficient food to grow to 15 centimetres and build enough muscle to finally embark on its epic journey to the sea. The fish must endure thousands of miles of open-ocean swimming to reach the rich feeding grounds of the North Atlantic. Then, if it is fortunate enough to evade predators and storms, it will, two or three years later, swim upstream against the current, surmount every obstacle in its path, and return to the gravel-strewn stream where it first hatched. It will spawn in this very place, which marks both its beginning and its end. Of those initial 8,000 eggs, only two will complete the entire life cycle described above. It is one of nature’s most astonishing feats.

To leave their freshwater river homes and venture into the salty ocean, salmon undergo a physical transformation known as anadromous migration. Millions of years ago, as the oceans cooled and became richer in food, salmon evolved this biological trait. This process allows the fish to ‘silver’; their bodies become more streamlined, their skin turns a reflective silver, helping them camouflage better in the open sea.In rivers, salmon are highly territorial and aggressive; but as they swim into deeper waters and join larger schools, their temperament grows milder. In the lower stretches of the river, closer to the sea, salmon take one final sample of the water’s chemical signature before leaving. Scientists believe it is this ‘imprint’ that guides them home after thousands of miles in the ocean.At the estuary, where fresh and salt water meet, salmon adapt their gills and breathing patterns to cope with the new environment, swimming near the surface. There, they feed on larger prey such as crustaceans, squid, small fish, and krill. Yet, while they hunt, they too become prey. Their predators include cormorants, sharks, sea lions, seals, and, of course, humans.

This remarkable feat of the salmon population unfolds across the North Atlantic, spanning over 2,000 rivers and tributaries in Europe and North America. Atlantic salmon can be found as far north as Norway, south to Spain and Portugal, east to Russia, and west to Canada. Yet, regardless of their origins, Atlantic salmon eventually converge on the waters off the west coast of Greenland and the Faroe Islands to feed. Here, every salmon grows to twice its size and puts on fat reserves to withstand the harsh North Atlantic cold and fuel their migratory journey.

Many aspects of the salmon’s life cycle belong in what Rachel Carson called the ‘ultimate mystery’. We do not truly understand how salmon navigate their migration (perhaps a combination of memory, scent, celestial cues, and the Earth’s magnetic field), nor do we know how they determine when to return. All we know is that they will return at any cost. Near Clooneen in County Donegal, Northern Ireland, along the 40-mile-long River Finn, salmon face what appears to be an insurmountable obstacle. Water cascades down a 10-foot waterfall, crashing violently against hard rock.Salmon swim up from the plunge pool below and attempt leap after leap. Some flick their tails to vault off the water or rock face in a series of bounds, while others launch themselves completely airborne. At this stage, migrating salmon are still burning through their energy reserves. Once back in the river, they cease feeding entirely, no matter whether it takes days, weeks, or months to reach their birthplace. Yet, having spent years hunting in the ocean, they are in peak physical condition. For the predators waiting along the riverbanks—both human and animal—the migrating salmon are therefore at their prime.

The poet Seamus Heaney has loved fly-fishing since childhood, angling for salmon east of Cloonagh Falls in County Donegal. He recalls seeing their silver-scaled bodies, blue-green fins, and torpedo-shaped heads as they burst through the water, straining to reach their natal waters. Heaney’s poem “To a Salmon” was published in 1969.At that time, the wild Atlantic salmon population stood at around ten million. Today, that number has fallen to fewer than two million. By contrast, another species—the Pacific pink salmon (which shares an evolutionary lineage dating back 20 million years)—still returns to its birth rivers in tens of millions.This is precisely why the dramatic decline of the Atlantic salmon is so alarming. Fifty years ago, half of every million salmon leaving rivers for the Atlantic would successfully complete their migration, spawn in their home waters, and fulfil their life cycle. Today, that figure stands at just 30,000. Despite global efforts to understand what lies behind this crisis, we still lack a clear answer as to why Atlantic salmon have suffered such a steep decline. For any species, when numbers drop this low, the future becomes precarious. Some marine scientists believe that the wild Atlantic salmon could genuinely face extinction.

The primary feeding grounds for Atlantic salmon lie off the west coast of Greenland, where thousands of fish from various rivers congregate. Today, these waters have become a target for industrial fishing. In the 1970s, Norway’s large-scale fleets could catch between two and three million salmon annually—more than the current global salmon population. It was not until the 1980s that an international agreement was finally reached to halt the unchecked plunder. Today, most commercial salmon fishing has been banned. In Ireland, only a handful of traditionally licensed fishers are permitted to fish in the estuaries. In Scotland, the wider UK, and Norway, driftnet fishing has also been drastically reduced. Yet, salmon numbers continue to decline. Our rivers and seas are facing serious problems.

Ken Whelan, Ireland’s foremost salmon scientist, points to shifting ocean temperatures as a major contributing factor. He says, “In parts of the salmon’s feeding grounds, the plankton has already disappeared.” Meanwhile, new species are appearing along Ireland’s south coast. “Warming waters have drawn in the Caribbean triggerfish and the Mediterranean sea bream, which now compete with salmon for food. The ocean is changing, and salmon are among the victims.”

And so the paradox emerges. Although wild salmon stocks are falling, the total Atlantic salmon population is actually rising rapidly. It is estimated that at any given time, around 400 million salmon are held within fish pens along the Norwegian coast alone. The number of salmon in just ten of these massive pens now exceeds the total wild salmon population across every river, stream, and the Atlantic Ocean combined. As wild numbers dwindle, farmed salmon thrive. Some believe the two trends are linked.

Most farmed salmon worldwide comes from a handful of Norwegian fish farming companies, including Lerøy and Salmar, with Mowi being the largest. Mowi operates farms across Norwegian waters, as well as in the Faroe Islands, Scotland, Canada, and Ireland, producing a volume that accounts for nearly a quarter of global consumption. The company’s global operations have even extended Atlantic salmon farming to the coasts of Chile, south of the equator. I was fortunate enough to tour Mowi’s farming operations from start to finish along Scotland’s west coast. At the hatchery, I saw newly hatched fry, their eyes still tightly encased in their egg sacs. Mowi runs 25 fish farms in Scotland. At one of them, I watched hundreds of thousands of salmon circling endlessly within the sea cages, with one occasionally breaking the surface to leap into the air. “I entered this industry as an environmentalist,” said Ian Roberts, a manager at Mowi, as he showed me around the farm, “I wanted to stop fishermen from harvesting the few wild salmon remaining in the sea, so I offered them an alternative.” This perspective took shape as, over recent decades, aquaculture has increasingly met the world’s growing demand for fish. More than half of the seafood humans consume now comes from aquaculture.