The Marine Conservation Society (MCS) has removed mackerel from its Fish to Eat list and placed the cheap oily fish, packed with Omega 3, on its Eat only Occasionally list. (Ethical Consumer magazine)

The charity says this is because mackerel have migrated into waters around Iceland and the Faroe Islands in search of their prey of squid and crustaceans, and are now being caught in vastly increased numbers by the fishing industries of these countries.

Those wanting to keep up their intake of Omega 3 are advised that sardine and herring are good sustainable alternatives to mackerel.

Another fish MCS have recently moved to their cautionary list is gurnard.