Mackerel is a fish that can be cooked from Raw mackerel with a Cooking level of 10. When cooked, it grants 60 Cooking experience (66 experience on a fire). When consumed, mackerel will restore 25 of a player's life points.
Mackerel may be required during the In Aid of the Myreque quest. When helping to repair the village Burgh de Rott you are either asked to bring 10 mackerel or 10 Raw snails, along with some other items so the general store can be reopened.