Major UK supermarkets are increasingly using the less nutritious and more cost-effective jack mackerel in their tinned fish, replacing Atlantic mackerel and igniting concerns from consumer advocates about both food quality and a lack of transparency.
The trend of opting for jack mackerel instead of Atlantic mackerel has gained traction at prominent stores, as longstanding overfishing has led to the decline of Atlantic mackerel stocks. Brands like Princes and Lidl’s private label are among those transitioning to this alternative species, which is distinctly different from its predecessor.
Reduced nutritional value, major price cuts
While Atlantic mackerel contains twice as much omega-3 fatty acids and three times the vitamin B12 compared to jack mackerel, the replacement products often remain similarly priced on shelves. Data compiled by Undercurrent, a seafood market analyst, shows that wholesale Chilean jack mackerel costs only about a third of the price of Atlantic mackerel. The Chilean species is marketed as a sustainable option, yet campaigners argue that inadequate labeling and less-than-transparent product changes make it difficult for consumers to make informed choices.
Sue Davies of Which? voiced strong opposition to this emerging trend, highlighting how “shoppers can end up paying the same price for a product that delivers significantly less nutritional quality” when manufacturers substitute staple foods without clear notification. Davies linked this behavior to “skimpflation”—a practice in which companies quietly alter or downgrade products while keeping prices constant, a move she described as “particularly sneaky” since customers may not realize what has changed until after purchasing.
Industry and regulatory landscape shifts
These changes are unfolding during a period of evolving regulations. Technically, jack mackerel is not a true mackerel but a Carangidae family fish, as opposed to the Scombridae group of Atlantic mackerel. Up until December 2025, UK labeling laws only allowed Carangidae fish to be described as “jack”, “scad”, “trevally”, or “horse mackerel”. After the release of Princes jack mackerel tins, the Department for Environment, Food and Rural Affairs revised rules to permit labeling as “jack mackerel”, paving the way for these substitutions on the UK market.
In October, Princes announced its intention to move all tinned mackerel products over to jack mackerel, which is certified by the Marine Stewardship Council (MSC) for meeting sustainable fishing standards. According to the company, the packaging now clearly differentiates the product and touts a “milder flavour and meatier texture” following trials and consumer feedback. Lidl GB, for its part, states a continued commitment to fish from responsibly managed sources.
The Scottish Pelagic Fishermen’s Association has expressed concern about newly permitted labelling, warning it could mislead customers. CEO designate Hannah Fennell pointed out that replacing North-East Atlantic mackerel with Chilean jack mackerel could not only challenge UK fishers but might also increase the carbon footprint for UK shoppers.
Atlantic mackerel decline leads to global industry shift
Ongoing international arguments over catch quotas—referred to as the “mackerel war”—have entangled the UK, Norway, Iceland, Greenland, the EU, Faroe Islands and Russia. Data from the Marine Stewardship Council (MSC) shows that, for the last fifteen years, North-East Atlantic mackerel catches have averaged 39% above scientific advice.
The International Council for the Exploration of the Sea (ICES) estimates that Atlantic mackerel stocks have shrunk by nearly 75% in the past ten years and has urged a roughly 70% reduction in catch allowances for 2026, calling the situation urgent for conservation. Because stocks are now described as at “breaking point” by the Marine Conservation Society, MSC certification for Atlantic mackerel has been removed.
Waitrose, responding to tightened supply, has decided to stop selling fresh, chilled, and frozen mackerel and will gradually discontinue its tinned mackerel as existing stock runs out. The retailer has been commended by the Marine Conservation Society for showing “leading and decisive” action.
This pattern of change is visible in other countries, too. Dutch supermarkets are eliminating Atlantic mackerel from their offerings, and at least one supermarket in Sweden has transitioned to jack mackerel as well.
Faced with these adjustments, consumers must grapple with less-obvious changes in what is actually inside the tin—often discovering differences in nutrition and labeling only after purchase.