Despite its name, horse mackerel is not a type of mackerel. Horse mackerel belongs to the fish family Carangidae, while traditional mackerel belongs to the family Scombridae.
Until December 2025, under UK law, Carangidae species could only be sold as ‘jack’, ‘horse mackerel’, ‘trevally’ or ‘horse mackerel’.
But shortly after Princes introduced its new product called Mackerel, the Department for Environment, Food and Rural Affairs changed its rules to allow the labelling.
Industry data released by seafood market intelligence platform Undercurrent shows Chilean mackerel wholesale costs about a third of the price of Atlantic mackerel.
The move follows the so-called “mackerel war”, a long-running dispute between the UK, Iceland, Greenland, Norway, the Faroe Islands, the EU and Russia over overall mackerel fishing quotas.
Countries have repeatedly failed to agree on a common system for allocating stocks and setting catch limits in accordance with scientific advice.
Over the past 15 years, mackerel catches in the northeast Atlantic have exceeded scientifically recommended levels by an average of 39%, according to the Marine Stewardship Council (MSC).
Stocks have fallen by about three-quarters over the past decade, according to the International Council for the Exploration of the Sea (Ice).
An intergovernmental body has recommended cutting the amount of mackerel caught in the northeast Atlantic Ocean by about 70% in 2026 to give stocks a chance to recover.
Last year, the Marine Conservation Society said the Atlantic mackerel population was at a “tipping point.”
The severe decline in mackerel numbers has led to the fish losing its MSC certification, meaning it no longer meets many retailers’ sustainability policies. Chilean horse mackerel, on the other hand, is MSC certified.
In February, Waitrose said it would suspend sales of fresh, chilled and frozen mackerel due to concerns about overfishing, while canned products would be phased out as existing stocks were sold.
The Marine Conservation Society called the move “landmark and decisive.”
The switch to horse mackerel is being felt outside the UK, with supermarkets in the Netherlands no longer selling Atlantic mackerel and at least one supermarket in Sweden switching to horse mackerel.