UK consumers are being warned of a significant shift in the tinned fish aisle as major retailers and brands replace traditional North-East Atlantic mackerel with a different species. The consumer group Which? has labeled the transition as “skimpflation,” noting that while the new product is often sold under the same “mackerel” banner, it offers fewer nutritional benefits and costs significantly less for retailers to source.
The transition has accelerated throughout 2026. Major supplier Princes has completed a shift of its branded range to Chilean jack mackerel for supermarkets including Tesco, Sainsbury’s, and Lidl. This follows a move by Waitrose, which suspended all sourcing of fresh, chilled, and frozen North-East Atlantic mackerel in April 2026.
Nutritional and Financial Discrepancies
While both species share a name in common parlance, they are biologically distinct and provide different dietary values. Traditional Atlantic mackerel (Scomber scombrus) is highly regarded for its high concentration of healthy fats. In contrast, Chilean jack mackerel (Trachurus murphyi) contains approximately 50% less Omega-3 fatty acids and roughly 100 fewer calories per 100g.
The financial motivation behind the swap has also come under scrutiny. Wholesale Chilean jack mackerel reportedly costs approximately one-third of the price of traditional Atlantic mackerel. Despite this 66% reduction in wholesale costs, retail prices for the tinned products have largely remained stable, leading to the “skimpflation” designation by Which? on September 12, 2026.
The Sustainability Trade-off
Retailers and suppliers maintain that the shift is driven by environmental necessity rather than profit alone. According to The Guardian, Atlantic mackerel stocks in the North-East Atlantic have plummeted by 75% over the last decade. This collapse is the result of what has been termed the “Mackerel War,” a series of failed international quota negotiations between the UK, Norway, and the Faroe Islands, which led to significant overfishing.
As a result, North-East Atlantic mackerel is currently “red-listed” by the Marine Conservation Society. Chilean jack mackerel, however, is frequently MSC-certified, allowing supermarkets to meet sustainability targets that traditional mackerel can no longer satisfy.
How to Identify the Change
Shoppers looking to distinguish between the two products must look past the large “Mackerel” branding and examine the fine print or the scientific names on the label.
- Scomber: This genus indicates true North-East Atlantic or Pacific mackerel, the traditional oily fish high in Omega-3.
- Trachurus: This genus identifies Jack mackerel, the leaner alternative currently populating more shelves.
Lidl confirmed its transition to the MSC-certified Chilean variety this month, joining a growing list of retailers moving away from the North-East Atlantic stocks. While the move helps protect depleted Atlantic populations, health-conscious consumers may need to adjust their portions or seek other oily fish, such as sardines or herring, to maintain the same Omega-3 intake levels previously provided by a single tin of Atlantic mackerel.
