Mackerel is no longer a sustainable choice for a regular fish supper, conservationists have warned in the face of overfishing of the stock.
The Marine Conservation Society said it had removed mackerel, an oily fish packed with omega 3, from its latest version of its "fish to eat" list, and it should be eaten only occasionally.
The warning comes after the Marine Stewardship Council, which certifies fish stocks that are managed sustainably, suspended its certification of the north east Atlantic mackerel fishery.
Atlantic populations of mackerel have moved north west into Icelandic and Faroe Islands waters, prompting their fishermen to fish more stock than was previously agreed and causing a dispute between the countries that target the fishery.
Bernardette Clarke, fisheries officer at the Marine Conservation Society (MCS), said: "The stock has moved into Icelandic and Faroese waters, probably following their prey of small fish, crustaceans and squid.
"As a result, both countries have begun to fish more mackerel than was previously agreed.
"The total catch is now far in excess of what has been scientifically recommended and previously agreed upon by all participating countries. Negotiations to introduce new catch allowances have so far failed to reach agreement."
The conservation group said good alternatives to mackerel were herring and sardine, and if people wanted to continue to buy mackerel, they should ensure it is as sustainable as possible - for example, fish caught locally using traditional methods.
Another fish taken off the "fish to eat" list is gurnard, because of a lack of data on population levels and concerns about how stocks of the increasingly popular fish are being managed.
Because the fish has been historically caught accidentally as "bycatch" by fishing vessels targeting other species, there are no catch restrictions - but if stocks are being increasingly targeted, they need to be managed sustainably, said the MCS.