'Skimpflation' warning as tinned mackerel alternative hits more supermarket shelves
Consumer group Which? has called the sale of jack mackerel, a cheaper, less nutritious species of fish, an example of "skimpflation".
A warning about “skimpflation” has been raised as more supermarkets stock a cheaper tinned mackerel substitute.
Sales of fresh mackerel have also been suspended by some shops because of overfishing concerns.
A consumer group has said the growing move by supermarkets to sell a less nutritious, lower-cost alternative to tinned mackerel is an example of “skimpflation”.
Princes, which supplies major supermarkets, has replaced the fish with jack mackerel, a completely different species that is also sold by Lidl.
The change has been driven by falling Atlantic mackerel stocks after years of overfishing, with the Chilean alternative being more sustainable and costing a third as much.
“It’s a real concern when manufacturers quietly downgrade everyday staples like these as shoppers can end up paying the same price for a product that delivers significantly less nutritional quality,” Sue Davies, head of food policy at Which?, said.
Jack mackerel has around half the omega-3 and about a third of the vitamin B12 found in conventional mackerel.
The change has led some consumers to complain about differences in taste and texture, along with worries about how clearly the substitute fish is labelled.
Lidl sells jack mackerel under its own brand. Lidl GB said it was “committed to sourcing fish and seafood from responsibly managed fisheries”.
Davies from Which? said: “While manufacturers face genuine supply chain pressures and sustainability challenges, they have a responsibility to shoppers to be completely upfront when they change a product’s recipe.”
She added: “Skimpflation - quietly changing ingredients to cut costs - has become increasingly common, but it can feel particularly sneaky as shoppers may not realise a product has changed until they get it home and eat it.”
Despite the name, jack mackerel is not actually a type of mackerel. Jack mackerel is part of the Carangidae fish family, while traditional mackerel belongs to the Scombridae family.
Until December 2025, UK law allowed Carangidae species to be marketed only as “jack”, “scad”, “trevally” or “horse mackerel”.
However, shortly after Princes introduced its new product as “jack mackerel”, the Department for Environment, Food and Rural Affairs changed its rules to allow the label.
Industry figures reposted by seafood market intelligence platform Undercurrent indicate that wholesale Chilean jack mackerel costs about one-third as much as Atlantic mackerel.
The switch comes after the so-called “mackerel war”, a long-running dispute between the UK, Iceland, Greenland, Norway, the Faroe Islands, the EU and Russia over shared mackerel catch quotas.
The countries have repeatedly failed to agree on a single system for dividing the stock and setting catch limits in line with scientific advice.
According to the Marine Stewardship Council (MSC), mackerel catches in the north-east Atlantic have been 39% above the levels recommended by scientists on average over the past 15 years.
The International Council for the Exploration of the Sea (Ices) says stocks have fallen by about three-quarters over the past decade.
The intergovernmental body has recommended cutting the amount of north-east Atlantic mackerel caught in 2026 by about 70% to give the stock a chance to recover.
Last year, the Marine Conservation Society said the Atlantic mackerel population was at “breaking point”.
The sharp decline in mackerel numbers has caused the fish to lose its MSC certification, meaning it no longer meets many retailers’ sustainability policies. Chilean jack mackerel, by contrast, is MSC-certified.
In February, Waitrose said it would stop selling fresh, chilled and frozen mackerel because of overfishing concerns, while tinned products would be phased out as current stock was sold.
The Marine Conservation Society described the move as “leading and decisive”.
The move to jack mackerel is being felt outside the UK too, with supermarkets in the Netherlands no longer selling Atlantic mackerel and at least one supermarket in Sweden switching to jack mackerel.