Salmon

If Aquaculture were a job applicant, her résumé would list salmon as a key career achievement. If she’d had today’s economic heft 150 years ago, she might have been represented allegorically on the façade of civic buildings, cradling a salmon in her arms. Judging by sheer quantity if nothing else, Salmo salar – Atlantic salmon – is the crowning success of fish farming. It is its vindication, its bounty. We see farmed salmon at every turn: in a fish pie or sandwich or bagel; on delivery pizza; shredded through pasta; as tartare, or as sashimi, or in a California roll.

Faced with this omnipresence, we may want to rewind a little and remind ourselves where this fish, so attractively pink-fleshed as to have a colour named after it, comes from. Its distribution in the wild mirrors almost exactly that of cod – before cod thinned out. From Arctic Russia, salmon grounds swoop along western Europe’s Atlantic seaboard and into the Baltic, fan out to Iceland and Greenland, embrace the Grand Banks and Maritime Canada, and come to hug the coast of New England. To which we must add – totally unlike cod, this – the river system of Europe and North America. Salmon are anadromous (from the Latinized Greek for “upward-running”): they hatch in freshwater, migrate to the ocean, and return upriver to spawn. As they change habitat, their livery veers between a sea-compatible silver and a more riverine camouflage tinge. After spawning, they die, though not always.

Atlantic salmon has relatives, some “true” salmon, some not. They include Pacific species such as the sockeye (Oncorhynchus nerka), whose body (but not head) turns a deep cyclamen during spawning. Some varieties are lakelocked. Some shade off into trout, a close cousin: within the broad Salmonidae family, biological boundaries can be fluid. But of Salmo, there’s only one. This is the one we know, in common parlance, as “salmon,” with no qualifier needed. This is the one we enjoy caught in the wild, with its deep pink, quasi-orange shade from feeding on red krill; and more often farmed, with its lighter, more marbled flesh.

The extent to which salmon has been democratized, and the speed of it, has few parallels in history. Global consumption has tripled in one generation, and most of it is farmed fish. In 2019, the BBC reported that UK residents consumed one million salmon meals every day. This, in a country where wild salmon is no longer fished commercially. Salmon aquaculture, in fact, has been described as the world’s fastest-growing food-production system. It’s as if we saw something in nature, something luxurious and desirable, and 3D-printed it to our heart’s content. In the process, salmon has been put to entirely new uses. Thirty years ago, the notion of salmon sashimi was still incongruous to most Japanese. The species was thought too fatty, prone to spoilage and parasites – until Norwegian salmon farmers, looking to mop up overproduction, conjured it as a marketing strategy. This wasn’t happenstance: Norway is credited with having the highest-quality strains of wild salmon, and hence the best fingerlings for hatcheries. The country is by a long stretch the world’s largest producer. Next up is Chile. Between them, the two nations cover two-thirds of the market.

Salmon farming has had its share of bad rap, largely to do with the low mobility of the fish in pens and cages; with the occasional escape of farmed animals, which can theoretically weaken wild populations; or with contamination of the sea, where insufficient water flows cause concentrations of salmon excrement.

As in other cases involving aquaculture, the criticism is part valid, part not, and part dated. Excessive crowding does happen. But the idea of having the fish still or barely hovering, like straphangers in the commuter crush, runs counter to market logic. Salmon is a capital-intensive, mass premium product: farmers have every interest to grow the fish to the ideal market size in the most efficient way. This entails keeping them healthy. Conversely, packing cages too tightly is counterproductive: it means shelling out more for costly fingerlings and reaping lower profits from smaller, weaker animals.

Still, farmed salmon are by definition more static than wild counterparts. In Norse lore, salmon was a symbol of sprightly elusiveness: the prankster god Loki, a master shapeshifter, is said to have turned himself into one to escape other gods’ wrath. Today’s farmed salmon are fatter and dowdier. Then again, they tend to be more nutritious: thanks to their optimized diets, unavailable in Viking times, they can be richer in omega-3 acids. (Farmed salmon are fed something called kibble, a combination of vegetable meals and fish-based meal and oil.)

Yes, it’s not unheard of for farmed animals to escape. That said, salmon pens and cages tend to be placed in bays, fjords or lochs, where outer islands protect them from oceanic storms and winter gales. Submergible cages, more resilient to disruption from waves, have been developed. The very severity of escape incidents is meanwhile being questioned. In 2022, Chile’s Constitutional Tribunal threw out heavy fines levied against one island farm which had seen more than 600 000 salmon break out of their pens during a violent storm. The judges ruled there was no scientific proof of environmental damage in escape cases, and that presuming detrimental impacts was unconstitutional.

As for sea contamination from large quantities of excrement, farming sites can be rotated – much like in agriculture, where fields are left fallow to allow soils to regenerate. One newer, more pristine option is to sever the marine link entirely. Research money has poured into land-based salmon farming, a closed-loop technology based on recirculation aquaculture systems (RAS). This allows for almost completely controlled environments. In 2020/21, RAS salmon firms were a sensation on the Oslo stock exchange. But with kinks still to be ironed out – the process depends on constant, finely calibrated oxygen and electricity supplies: an accident at one farm in Denmark, in the summer of 2021, wiped out almost a fifth of its biomass – investors have grown warier and shares have fallen back.