There are so many old, old ways of cooking, which are on their way to oblivion, a pity. Like this one, some date back to times when there was no refrigeration, and ways had to be found to preserve foods. This is still a beloved dish. It can be found on the canned foods shelf of every supermarket, but the commercial product does not use the "right" kind of fish: it should be firm-fleshed and not mushy. This recipe can be halved or quartered. Very large ocean fish (beloved by sports fishermen and usually caught off boats) usually have coarse flesh which is not good for the usual plain treatment but they are ideal for pickled fish. Prep time is a guess, and depends on many factors, such as: are you going to fillet the fish?