🐟 Why Most Supermarket Salmon in the UK Is Unsustainable- and which one should I buy?

It's Christmas!🎄 That means it's time for your festive foods to come front-of-stage- such as smoked salmon! But what if i told you the shocking truth about how the salmon you're eating is produced... and more importantly the impact it's having on the environment. There is a really important swap you can make in your food shop this Christmas (and beyond) that genuinely makes a positive difference to our oceans...

The ocean is our planet’s most powerful defence against climate change and biodiversity collapse- and it’s continuously under threat. One of the major drivers of this threat is the fishing industry, of which salmon plays a significant role within the UK.

Most of the salmon sold in UK supermarkets, particularly Scottish (also Norwegian/Irish/Faroese) salmon, comes from farms that pollute coastal waters, amplify parasites, and put wild fish and marine life at risk. The reassuring sustainability labels you see on supermarket salmon packs sadly largely don't reflect the true impact of its production and the conditions these fish are grown in.

Scottish farmed salmon with severe sea lice damage. ©CorinSmith

Many consumers are unaware that what they’re buying is farmed rather than wild. A survey found only ~6% of UK consumers knew Scottish salmon is farmed. Source: Best fishes

🎉 There is a sustainable option though!

Wild Alaska salmon however is protected by some of the strongest fisheries laws on Earth. No farms, no chemicals, no shortcuts. This Christmas, the choice is simple- avoid farmed Scottish salmon and choose genuinely sustainable wild alternatives, like LEAP Wild Alaska Salmon available at the likes of Tesco, Waitrose, Sainsburys and Asda.

https://www.leapwildfish.co.uk

🌊 Why Scottish Farmed Salmon Isn’t Truly Sustainable

Aerial view of Scottish salmon farm pens source:wildfish.org

🐛 1. Open-Net Pens = Pollution & Parasites

The majority of Scottish salmon is raised in open-net pens in sea lochs. These systems allow waste, uneaten feed, chemicals, and parasites to circulate freely into the surrounding marine environment- impacting wild ecosystems.

One of the most persistent challenges is sea lice (often called “mites” by fishers and consumers). They thrive in crowded pens, leading farmers to use chemical treatments or mechanical delousing systems that can harm the fish, leave residues, and further stress the entire local marine environment. 

This isn’t just an ecological problem- it affects the quality of the salmon we eat. Farmed salmon tends to have higher fat content and can accumulate more contaminants than wild salmon, partly because of feed additives and drug use to control disease. 

credit: intrafish

Sea Lice: A Growing Threat to Wild Salmon

Sea lice occur naturally in the ocean, but intensive salmon farming can dramatically increase their numbers. A recent modelling study commissioned by WildFish Conservation found that sea lice originating from salmon farms in Scotland’s Northern Isles could disperse across vast areas of coastal water, overlapping with migration routes used by wild salmon from rivers along Scotland’s east and north coasts.

The study suggests that young wild salmon passing through these waters may be exposed to elevated lice levels linked to nearby farms, increasing stress and reducing survival during a critical stage of their lifecycle. While direct cause-and-effect links are complex, the research adds to growing evidence that open-net salmon farming can significantly amplify sea lice pressure on wild fish- a risk that wild populations cannot escape.

Not just wild salmon are contracting lice from these farms... sea trout swimming close to salmon farms in Ireland and in Scotland have been found to be carrying significantly higher levels of sea lice infestation than those swimming further away from such farms. Read the article here!

🐟 2. Waste & Habitat Damage

Each farm releases tonnes of waste and uneaten food into the water. Because open-net farms lie directly in tidal flows, there’s no filtration or waste management- meaning benthic habitats beneath pens can become suffocated and unable to support life. 

This creates local dead zones and disrupts the ecological balance of sea lochs that once supported diverse communities of shellfish, sea stars, and wild fish.

Harvested fish for salmon farm feed. ©Fish Information Services (FIS) (2024).

There's also the aspect of the food used to feed these salmon- it seems such a waste... other fish are caught to use as feed. Fish that could be used to feed humans, or left in the ocean!

🦭 3. Wildlife Conflict: Seals and Salmon Farms

A seal found shot at Basta Voe. Photo: Lizzie Daly

Scottish salmon farms have long struggled with seal predation — sea lions, grey seals, and other marine mammals are attracted to the fish in pens. Rather than changing farming systems, the industry has historically resorted to lethal control of “problem seals.”

Although legal and regulatory pressures have tightened, this conflict highlights a deeper ethical issue: systems that require killing native predators to operate are inherently unsustainable.

🌍 The Best Salmon Comes from Healthy Wild Fisheries

In contrast, wild-caught salmon from Alaska represents one of the few genuinely sustainable salmon sources available to UK consumers:

✔ Wild & Naturally Regulated

Alaskan salmon fisheries are governed by strict laws that require sustainable harvest based on annual stock assessments. If a stock drops below conservative thresholds, harvest limits are reduced to safeguard future seasons. This isn’t voluntary — it’s written into state policy. 

✔ No Farms, No Nets in the Ocean

Wild salmon swim freely throughout their lifecycle, feeding naturally and avoiding the health issues common in crowded aquaculture. They aren’t exposed to antibiotics, chemical delousing, or farm-based disease cycles.

✔ High Nutrition, Lower Contaminants

Because they grow in their natural ecosystem with varied diets and high activity levels, wild salmon generally have:

• More diverse omega-3 profiles

• Leaner muscle tissue

• Fewer chemical contaminants

These qualities make wild salmon not just more sustainable — but also healthier for human consumption. 

⁉️ So why can't we buy wild Scottish salmon in the supermarkets?

📉 Limited supply: Wild Scottish salmon is only available seasonally and in small quantities from certain rivers.

💰 High cost: Catching wild salmon is labor-intensive, making it much more expensive than farmed salmon.

🍃 Sustainability and regulations: Strict quotas and licensing prevent overfishing and limit the amount available for sale.

🍽️ Consumer demand and marketing: Supermarkets prioritise farmed salmon because it is consistent in size, taste, and price.

🏆 A Good Choice Available in the UK:

LEAP Wild Alaska Salmon

Sockeye salmon in Briston Bay, Alaska, just about to head upriver to spawn. credit: vital choice

In the UK, one of the most accessible genuinely sustainable options is LEAP Wild Alaska Salmon — a brand that partners with sustainable Alaskan suppliers to bring 100% wild-caught salmon directly to consumers. This supply chain prioritises:

• Wild harvest

• Traceability

• Environmental stewardship

• Premium quality and nutritional integrity 

LEAP has also been part of campaigns with the Alaska Seafood Marketing Institute to raise awareness of Alaska’s wild salmon benefits here in Europe. 

🧾 Final Takeaways — Eat Better, Not Just More

A brown bear snags a sockeye salmon in midair on August 11, 2023, at Brooks Falls, Alaska, within Katmai National Park and Preserve credit: John Moore- Getty

🐟 Eat salmon mindfully- quality matters more than quantity.

🌿 Avoid supermarket farmed salmon if sustainability and health are priorities.

🇺🇸 Choose wild Alaskan salmon (like LEAP) for true sustainable sourcing.

🗣️ Share the word about sustainable salmon, and let me know if you'll be making the switch!

Best fishes,

Beth 🐟

This post is not sponsored, endorsed by or paid for by any organisations mentioned.