Consumer watchdog flags rise of low‑cost ‘jack mackerel’ as possible ‘skimpflation’ in UK supermarkets

Consumer advocacy group Which? has warned that the growing shelf‑space given to tins of jack mackerel – a cheaper, nutritionally inferior relative of the traditional Atlantic mackerel – may represent a new form of "skimpflation". The term, coined by the group, describes a subtle erosion of product quality or quantity while prices appear stable, leaving shoppers with less value for the same outlay.

Skimpflation differs from outright price inflation in that the sticker price remains largely unchanged, yet the product’s substance is quietly reduced. In a climate of persistent cost‑of‑living pressures, retailers are under increasing pressure to keep shelves stocked without passing higher raw‑material costs onto consumers. Substituting a lower‑priced fish species is one way to achieve that balance, but it also raises questions about the hidden cost to public health.

Jack mackerel (Trachurus spp.) is a smaller, faster‑growing species that commands a lower market price than the richer, oil‑laden Atlantic mackerel (Scomber scombrus). While both belong to the same family, the former contains significantly less omega‑3 fatty acids and overall protein, making it a less nutritious option for consumers who rely on canned fish as an affordable source of essential nutrients.

Supermarket chains have responded to tightening margins and volatile fish supplies by expanding their range of canned jack mackerel, often marketing it under generic "mackerel" labels. Analysts attribute the shift to rising wholesale costs for Atlantic mackerel, tighter fishing quotas, and the impact of Brexit‑related trade disruptions on import volumes. The result is a broader visibility of the cheaper alternative on everyday grocery aisles.

For shoppers, the substitution can be difficult to detect, especially when packaging does not clearly differentiate the species. Which? points out that many consumers may assume they are purchasing the same health‑benefiting fish they have bought for years, potentially compromising dietary goals without realizing it. The group advises shoppers to read the fine print, looking for scientific names or specific species listings, and to compare nutritional information on the back of the tin.

Industry bodies and food‑safety regulators have yet to comment formally on the issue, but Which? says the episode underscores the need for stricter labeling standards. If the practice spreads, it could prompt the Food Standards Agency to revisit guidelines on species disclosure for canned fish products. In the meantime, the consumer group urges buyers to stay vigilant and consider alternative protein sources if nutritional content is a priority.