Of the four species considered for exploitation, the population structure of blue mackerel is uncertain, and jack mackerel and redbait are believed to have eastern and western subpopulations.

It's against this premise we can thank our lucky stars the foreign-owned factory ships that eyed our blue mackerel fisheries a few years back were sent packing. Consider, on the other hand ...

As of this weekend, the Marine Stewardship Council (MSC) has warned people against purchasing mackerel caught in the North East Atlantic, which will no longer bear its “blue label”.