Supermarkets Swap Your Mackerel for a Cheaper Fish, Call It 'Skimpflation'

In a development that will surprise absolutely no one who has ever watched a shrinkflation documentary, supermarkets are now quietly swapping tinned mackerel for a cheaper, less nutritious fish. Consumer group Which? has dubbed this phenomenon "skimpflation" - because "we're cutting costs and hoping you don't notice" was too long for a headline.

Princes, which supplies major supermarkets, has substituted traditional Atlantic mackerel with jack mackerel, an entirely different species that Lidl is also selling under its house brand. The switch comes courtesy of dwindling Atlantic mackerel stocks after years of overfishing. Chilean jack mackerel is more sustainable and costs about a third as much. So, silver lining: your fish is cheaper for them, not for you.

"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," said Sue Davies, head of food policy at Which?. In other words, you're paying premium prices for a fish that's about half as rich in omega-3 and around a third as rich in vitamin B12 as the real deal. Bon appétit.

The shift has prompted complaints from consumers about differences in taste and texture, as well as concerns about how clearly the replacement fish is labelled. Because nothing says "transparency" like a fish that isn't actually a mackerel being sold as "jack mackerel."

Princes announced last October that it was changing all of its tinned mackerel products to jack mackerel, saying the species meets the Marine Stewardship Council's sustainability standards. The firm said its jack mackerel products were "clearly identified" and had been introduced following extensive product and consumer testing, describing it as having a "milder flavour and meatier texture." Lidl GB, meanwhile, 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." Which is, of course, the exact moment you realise your dinner tastes like disappointment.

Despite its name, jack mackerel is not a type of mackerel. Jack mackerel belongs to the Carangidae fish family, while traditional mackerel belongs to the Scombridae family. So they're not even distant cousins. They're more like acquaintances who nod at each other at industry conferences.

Until December 2025, under UK law, Carangidae species could only be marketed as "jack," "scad," "trevally," or "horse mackerel." But shortly after Princes launched its new product as "jack mackerel," the Department for Environment, Food and Rural Affairs changed its rules to permit the labelling. Because nothing speeds up regulatory reform like a multinational food company wanting to sell you cheaper fish.

Industry figures reposted by seafood market intelligence platform Undercurrent suggest wholesale Chilean jack mackerel costs roughly one-third as much as Atlantic mackerel. Your wallet, however, may not notice the difference.

The switch follows 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 unified system for sharing stock and setting catch limits in line with scientific advice. Diplomacy: it's like herding cats, but with more fish and fewer results.

Mackerel catches in the north-east Atlantic have exceeded the levels advised by scientists by an average of 39% over the past 15 years, according to the Marine Stewardship Council (MSC). Stocks have plummeted by roughly three-quarters over the past decade, according to the International Council for the Exploration of the Sea (Ices). The intergovernmental body has advised slashing the quantity of north-east Atlantic mackerel caught in 2026 by roughly 70% to allow the stock a chance to recover. Last year, the Marine Conservation Society said the Atlantic mackerel population was at "breaking point."

The severe depletion of mackerel numbers has led to the fish losing its MSC certification, meaning it no longer complies with many retailers' sustainability policies. Chilean jack mackerel, in contrast, is MSC-certified. So, to recap: the fish you used to buy is now unsustainable, and the fish you're getting instead is sustainable but less nutritious. Pick your poison - or rather, your fish.

In February, Waitrose said it would suspend sales of fresh, chilled, and frozen mackerel due to overfishing concerns, while tinned products would be phased out as existing stock was sold. The Marine Conservation Society heralded the move as "leading and decisive."

The switch to jack mackerel is being felt beyond the UK, with supermarkets in the Netherlands no longer selling Atlantic mackerel and at least one supermarket in Sweden switching to jack mackerel. So if you're in Europe and your fish tastes a bit off, now you know why.

In related news, scientists and fishermen are celebrating the return of tuna, while animal rights activists suggest a mackerel festival should celebrate cabbage instead. Priorities.