Farmed Salmon to Cause Wild Salmon Extinction?

Increasing pescetarianism and disposable incomes, and the meat’s well-documented health benefits meant that sales of salmon – once considered more of a luxury fish – rocketed, resulting in wild salmon not being able to supply the feverish demand. The answer seemed obvious; farming these hitherto wild animals. Unfortunately, as this recent article (1) makes clear, there’s no such thing as a literal free lunch.

Wild Atlantic Salmon are born and spend the first part of their lives in rivers, before physiologically adapting to salt water and heading out into the ocean to further mature (2). They undertake lengthy migrations of thousands of miles to feeding grounds, before their honing skills (using the earth's magnetic field, the chemical smell of their river and pheromones) bring them back to the exact same river in which they were spawned to start the whole process again. Impressive stuff. Mortality after spawning is significant, but some do survive to commence the epic journey again (and third journeys have been documented).

Farmed Salmon’s Meteoric Rise and Costs

The number of farmed Atlantic Salmon worldwide has increased 350% since 2000 (3). Norway is by far the largest producer of farmed salmon, with other big players being the UK, Canada, Chile, Australia and New Zealand. At 500,000, Norway’s wild salmon population is at an all-time low (4), and is dwarfed by the 2023 count of an astonishing 388 million farmed salmon – that’s over 750 times more farmed than wild salmon. In 2023, in a new record, 63 million or almost 17%, of Norwegian farmed salmon died prematurely. Surely, something must be wrong with a farming business that fails to get almost one in five of its animals to the plate.

Farmed Salmon have Increased 350%

Before we start finger pointing, this is not an issue specific to Norway. In the ten years up to 2021, the six leading nations mentioned above lost 865,000,000 salmon to premature death (5). In case you’re struggling to do the sums, that’s a lot of wasted dead fish.

The issue, of course, is that these animals haven’t evolved to live one on top of another as they are forced to in farming pens. There are various reasons for the high death rate when they’re all wedged in together including:

Existing and new diseases
Mechanical and thermal methods used to attempt to delice the salmon
Lice
Water quality problems
Overuse of antibiotics and antiparasitics causing bacteria and parasites to develop resistance

Just like flying fishing really

The farms also suffer from what are termed Mass Mortality Events, which as the name suggests, is when an awful lot of fish die in a very short period of time. Warming oceans haven’t helped, but fish all doing their business in a confined area and dead fish decomposing cause algae blooms, which starve the fish of oxygen leading to more deaths.

A New Type of Salmon Run

If they’re not dying, they’re escaping, which is hardly surprising, and escapees pose several threats to wild populations, with interbreeding being of most concern. There are a number of reasons for this being the key worry, but really, in layman’s terms, it boils down to the farmed salmon being a bit crap. Spreading disease and parasites to wild salmon is also a major issue, with increasing lice death in wild salmon reported. In the ten years to 2021, 1.73 million salmon were reported to have escaped from Norwegian salmon farms (6), and although this number is supposedly decreasing, it’s thought that this number was under-reported by 2-4 times (the salmon farmers not over keen to highlight the problem), so we can still safely assume there’s still quite a few making a break for it.

Impacts on the Wild Population

The effects on the wild population are certainly being felt, with this year 33 of Norway’s salmon rivers being closed in the fishing season, basically because the salmon failed to show up back from the Ocean. Torbjørn Forseth, a salmon researcher at the Norwegian Institute for Nature Research, says that this year’s salmon collapse is unlike anything he has ever seen in his 25 years of studying Atlantic salmon.

Much hand wringing is taking place. What to do, what to do? There’s talk of salmon farming being pushed to ‘closed units’ to ensure separation from the wild population, but Henrik Wiedswang Horjen, a spokesperson for the Norwegian Seafood Federation who may or may not have a conflict of interest on this issue, says that closed farm units are “much more energy-intensive” and could have a significant environmental impact. It would seem like we may have one of those already.

A Potential Solution?

What’s not being mentioned, the elephant in the room, is that perhaps we just eat less salmon. When there are hundreds and hundreds more farmed salmon than the wild population, if there was a ban on salmon farming we’d either wipe out the wild salmon in a few weeks, or it would be a delicacy only afforded by oligarchs and tech bros, so that’s not a realistic solution.

The idea of eating far less salmon might not be as crazy as it sounds. Farmed salmon are currently fed a diet including wild fish, many of which are perfectly edible such as mackerel, herring and anchovies. Ironically, as reported in this paper (7), summarised on the University of Cambridge’s website (8), six out of nine nutrients – calcium, iodine, iron, omega-3, vitamin B12 and vitamin A – found in the wild fish were reduced in farmed salmon. In other words, for those nutrients you’d be better off health wise eating the wild source rather than the farmed result, not even accounting for all of the issues raised in this post. Furthermore, all of the nutrients gained from the farmed or wild fish can be found in non-animal sources including various nuts and seeds. There’s even an omega-3 supplement made from algae.

Doing its Wild Thing

Over to You

The University of Cambridge summary also mentions that 24% of UK adults eat salmon weekly, so this is an issue many of us should probably be thinking about. We can pull the wool over our own eyes and wait for the ‘powers that be’ to come up with a solution, but it’s those very organisations, government and the seafood industry, that have led us to where we are today, so unfortunately it’s a problem that the consumer only can fix.

The marketing doesn’t quite tell the whole story

The question is, are you happy with the environmental sacrifice – quite likely the eradication of quite a cool wild species – required to continue eating salmon in the quantities we currently are? A return to the 1970s, when salmon was regarded as a luxury, would make a lot of sense.