Fish and chip fans are being urged to seek alternatives to Haddock from the North Sea and West of Scotland over fears of dwindling numbers.
Along with cod, tuna, salmon and prawns, haddock is a favourite at chip shops across the UK and makes up one of the nation's "big five" seafood species.
But now haddock from three North Sea and West of Scotland fisheries has been removed from the Marine Conservation Society's (MCS) "fish to eat" list.
Distinguished by a black line running along its white side, stock numbers of haddock fell below the recommended level in 2016 and action is now required to increase the number of fish of breeding age, according to the society.
The three fisheries no longer find themselves on the charity's recommended "green" list of fish to eat.
Bernadette Clarke, the MCS Good Fish Guide manager, said: "These ratings changes have come about because scientific perception of the stock has changed.
"Compared to 2015, the stock numbers in 2016 were below the recommended level and at the point where action is now needed to increase the number of fish of breeding age."
Two of the fisheries are now rated "amber" - scoring just four in a scale of one to five, where one is the most sustainable - in the MCS Good Fish Guide.
The other fishery has seen its fish drop from being a good choice of haddock to buy to one to eat only occasionally, with a "three" rating.
Elsewhere, scampi from Farn Deeps fishery has been upgraded from "five", the lowest ranking, to "four", but still remains some way off being sustainable.
Those purchasing American lobster are advised to choose ones which come from fisheries with a Marine Stewardship Council certification, which means they implement stronger management to protect stocks and habitat and prevent bycatch.
Consumers who want to check which fish to buy or avoid can visit www.goodfishguide.org.