Fish and chips at Padstow harbour in Cornwall, UK.
Photo: Adobe Stock
Several well-known seafood products eaten in the UK are facing growing sustainability concerns, according to an update from the Marine Conservation Society’s Good Fish Guide, which has downgraded some ratings for cod, widely served in British fish and chip shops, and langoustine, often sold as scampi.
The charity said its latest assessment, published on 9 April, found that some cod stocks from waters north of the UK had slipped further down its sustainability scale, leaving no recommended options for UK-caught cod.
The organisation notes that several UK cod populations have been declining since 2015 because of a combination of overfishing, warmer sea temperatures and wider ecosystem pressures affecting breeding and the survival of young fish.
Last September, the International Council for the Exploration of the Sea (ICES) recommended a full closure of the cod fishery in the North Sea and adjacent waters in 2026, citing continued concerns over the health of the stock, although this was not implemented. However, this advice was not implemented, with Norway, the EU, and the UK instead reaching an agreement to significantly reduce cod quotas.
The Marine Conservation Society guide, which uses traffic-light style ratings depending on where and how seafood is caught or farmed, also lowered some scores for langoustine. The charity said the downgrade reflected fishing levels that have been above scientifically advised limits in recent years, alongside falling populations.
It said the most sustainable langoustine options remained those caught by pot or creel rather than by trawl. The only three green-rated fisheries for the species, according to the update, are in North Minch, South Minch, and Skagerrak and Kattegat.
The latest changes also go beyond fish and chip shop staples. Mackerel, which the charity removed from its recommended list last year, has since been given a red rating, meaning consumers are advised to avoid it altogether. The Marine Conservation Society noted that some retailers, including Waitrose, have already taken mackerel off their shelves.
As alternatives to cod, the charity points to species such as European hake, which it says has healthy UK stock levels, and to some haddock fisheries, including catches from the North Sea and west of Scotland.
For consumers looking to replace langoustine, the guide has introduced a new rating for farmed king prawns produced in Scotland. "Farmed in a completely closed system, these prawns have a much lower environmental impact," the organisation said.
The update also draws attention to seafood the charity considers better choices from UK waters and farms, including seabass from the North Sea, English Channel and Celtic Sea, plaice from the North Sea, and farmed species such as blue mussels and freshwater trout.
Commenting on the findings, Kerry Lyne, Good Fish Guide Manager, said: "As pressure grows on traditional choices like cod and scampi, the Good Fish Guide highlights more sustainable alternatives and shows how consumer choices can support healthier local fish stocks and better-managed fisheries."
The charity said the UK imports about 80% of the seafood it consumes and argued that stronger domestic fisheries management is needed to rebuild stocks and reduce dependence on imports. Chris Graham, its head of sustainable seafood and ocean regeneration, said: "We need strong action from the UK Government to support a transition to low-impact fisheries and sustainable seafood farming."
The Good Fish Guide is updated twice a year in line with the latest scientific advice, with the next revision due in October.