From Kettner’s Book of the Table.

A great authority, Grimond de la Reynière, says: “The mackerel has has this in common with good women – he is loved by all the world. He is welcomed by rich and poor with the same eagerness. He is most commonly eaten à la maître d’ hôtel. But he may be prepared in a hundred ways; and he is as exquisite plain as in the most elaborate dressing” (au maigre coome au gras). This immense praise, and is a complete justification of the common English method of serving him  – plain boiled, with fennel or with gooseberry sauce. Nevertheless I give my vote to those who assert that there is but one perfect way of cooking a mackerel – to split him by the back, broil him, and serve him with maître d’hôtel butter. Still better, take his fillets and serve them in the same way.

The name of mackerel is supposed to be a corruption of nacarel, a possible diminutive of nacre – from the blue and mother-o’-pearl tint of skin. In one of the dialects of the south of France he is called peis d’Avril, the April fish – or as we should say, an April fool, both because he is a fool coming easily to the net, and because he first comes in April. He is not only quickly caught, but he spoils so quickly that the law accords him a peculiar privilege: he is the only fish that may be hawked from the street on a Sunday. For the same reason he is the only fish besides the salmon that is much soused or marinaded in the country.

The mackerel which comes to our shores is a great puzzle to the philosophers. He has no air-bladder, yet he is as buoyant and lively as fish can be. What then is the use of an air-bladder?