In the age of the sustainable fish, mackerel is king. Or at least first in line to the throne. It used to be regarded as a very low caste fish (but then, so did monkfish and sea bass once upon a time). Not anymore. It’s plentiful, for the time being anyway, with mackerel almost up there with sea bass and sea bream in the sustainability stakes. It’s easy to see why, you can catch it at different seasons all the way round the coast and it shoals in the most obliging way.

That distinctive, black-barred, gun metal-blue and silver skin gives it a dashing appearance on the fishmonger’s slab and plate, which chefs like. It has a fine, meaty flesh, which lends itself to portion control, and it has a most distinctive flavour. Sometimes it is a little too distinctive, which is a sure indication that the mackerel in question is not as fresh as it might be. And mackerel really does need to be very, very fresh.

There is another problem for the cook with mackerel; it is a very oily fish. This oil may be very beneficial for your joints or your memory but it can have a distinctly greasy effect on the dish. So you need to cook it in a fashion that leaches out the fat.

You can buy mackerel virtually all year round, but it is best to give them a rest in spring and early summer when they breed.

There’s something hard to resist about a fresh sardine, with its bright, inquisitive eye, shimmering scales, silver on the sides, darkening to gunmetal blue on top, and its neat, trim, perfect portion control shape rich in all sorts of good oils. I think we think of the sardine as the archetypal Mediterranean fish, grilled in the Portuguese fashion; fried in olive oil in the manner of Spanish; broken in bits and lined up with raisins, wild fennel and pine nuts to make a sauce for bucatini in the baroque style of Sicilians, and if you saw ‘Grilled Pilchard’ on the menu, you’d probably pass on with a barely suppressed shudder. And yet, what is a sardine, but a pilchard that hasn’t grown up?

Cornwall used to lead the world in pilchard production, still does, in a manner of speaking, even if they aren’t there in the numbers of old, According the peerless Alan Davidson in his majestic ‘North Atlantic Seafood, which should be on the bookshelf of every self-respecting cook, quoting Frank Buckland’s The Natural History of British Fishes (1883) one boat took 80,000 pilchards in a single night. There’s still a decent pilchard fishery there, and although you don’t often see fresh pilchards, they turn up in tins.

That’s the thing with sardines. They spread from Portugal, France and Spain, to Britain. They’re plentiful, so you can eat them with a clear conscience. And they’re versatile. The Italians eat them in their larval, known as neonati or gianchetti. And I’m very partial to a tinned sardine, kept in olive oil or spicy tomato sauce. Loaded onto toast with a slice or two of cucumber, they make a very decent light lunch. Still, fresh is best.

There was a time, a few years ago, admittedly, when fishmongers couldn’t give away sea bass. They were considered a very lower order fish. Then chefs discovered them, and found that a) they were cheap (back then); b) they cut up into nice portions; c) when scaled, their skins remained bright silver when cooked, and so looked very pretty on the plate; and their fate was sealed. They became the smart fish of choice, so much so that it became necessary to farm them to keep up with demand.

Of course, there’s a world of difference between a farmed sea bass and the wild variety. For a start there’s size. Wild sea bass can grow to double pound figures (although I’ve never caught one), while farmed sea bass tend to go to the 500g – 1kg size. And if you see a shoal of same sized sea bass on the fishmongers slab, you can bet that they were raised in cages off the coast of Greece of Tunisia or somewhere like that, and their flesh will not have the muscular tautness or the sweet flavour of the wild one.

They seem to be accepted as sustainable by most authorities, but, as with hand-picked scallops, go for the line caught fish. They’re what you might call a versatile fish and take to frying, steaming or being cooked en papillote equally well.

It may be hard to believe, but salmon raises deep passions. Salmon farmers defend their product with a vigour matched by few agriculturists. Salmon fishermen, loathe and despise the farmed variety for polluting beautiful waters, mongrelising the native wild salmon stocks, and generally lowering the tone of this most splendid, and delicious of fishes. There is no doubt that a spring-run salmon netted in the mouth of a river is just about the finest eating fish ever, rich and delicate, distinctive and dainty, firm and yielding. However, there aren’t very many of them, and we shouldn’t be eating them.

Autumn run fish are in a different state, and their stocks aren’t so threatened. Farmed salmon has the advantage of being available all the year round, and the same all the year round. There isn’t enough space here to rehearse the arguments about the environmental, chemical and welfare issues for the vast majority of salmon farms.

Simply on a gastronomic basis, the fatty, flabby, greasy, flavourless quality of the average salmon fillet is an affront to your taste buds. ‘Organic’ salmon (there is equally heated debate as to whether salmon can really be described as ‘Organic’) is better, and can be halfway decent. But no wonder supermarkets are experimenting with Alaskan and Pacific wild salmon (a different variety from our native Atlantic salmon), although the environmental footprint might raise an eyebrow in some circles. My advice is to substitute sea trout for salmon when in season (roughly from April-October).