We eat eggs. But one of the great delicacies is caviar, the roe, the eggs of a sturgeon. This giant fish is prevalent in the Caspian sea, and the eggs are collected from captive fish and sold on the markets. But sturgeon is not the only fish whose roe is consumed, for herring roe is also a delicacy, at its best in winter. However, some gourmets also consume the milt of the herring, which is the seminal fluid of the male fish, dried and powdered. It is said to be a delicacy. Herring roe used to be nicknamed poor man's caviar.
There is a Sardinian dish known as Botarga, which is milt and roe dried into a powder then pressed into a slab, which is then spread on pasta or toast. The roe of any fish can be used in this dish and it is said to be a delicacy, especially by the Sardinians. Yet there are fish in British waters whose roe is tasty, though there are some reservations about eating some of them. Cod and herring are popular, but pollack and ling have been used in roe dishes.
Ling is something of a problem for fishing and I have never eaten it or its roe. In the nineteenth century it was considered the poor man's cod, for it is a gaddoid, one of the cod family, and was eaten by impoverished Irish immigrants, so it became unfashionable. Lucky for the ling, as it is a large, slow growing fish, and so beam trawlers are forbidden to catch it. Small ling can be found near shore, but the large varieties, that it is permitted to catch with a line, like deep rocks and wrecks about a thousand feet down and so are impossible to trawl. Expert fishermen know where the rocks and wrecks are, but in the British Isles you are likely to find suitable water on the edge of the continental shelf off Ireland, so as I have never fished that far out there is no chance of my ever having caught a large ling. The ling has a large liver that used to be eaten with relish and its roe is tasty. But personally, I would not fish for it for ecological reasons.
There are plenty of recipes, far more than can be given in a short article, but I have listed a useful and informative work by my culinary guru, Hugh Fearnley-Whittingstall, of River Cottage fame, which contain a plethora of recipes for , as Hugh would say, fishy foodies.