The last, but by no means the least, important factor to be considered in estimating the food value of any particular fish is its retail price. The price of the different kinds of fishes is by no means proportional to their individual food values. It is determined primarily by the abundance or otherwise of the available supply of each individual species. Thus, the various pelagic fish—mackerel, herring, sprat—that are easily caught in enormous quantities at certain seasons of the year are by far the most valuable. Of trawl-caught fish, cod and whiting are more plentiful and are, therefore, cheaper than hake, although, again, the cheaper fish has the greater food value.

In some cases certain fish, although fairly abundant, are in poor demand owing to some prejudice on the part of the public, and are generally sold in poorer districts, or to the fried fish trade, at a disproportionately low price, for example skate, dog-fish, angler fish, john dory.

Taste and appearance also contribute to the popularity and, therefore, indirectly to the retail price of fish, such as the sole and the salmon.

In Table IV the present retail prices (Sept., 1921) and the food values of a number of different fishes are compared. From these figures, the actual food value per shillingsworth of each fish has been calculated.

The cheapest fish, therefore, are also those possessing the greatest food value, e.g. the herring in all its forms, dried cod and ling, and mackerel. These compare favourably both in cost and food value with meat, such as beef and mutton.

TABLE IV
Food Value per Shillingsworth of Different Fishes
Fish.Food
Value.		Retail
Price
Sept. 1921		Food Value
per
Shilling.
Cals.
per lb.		per lb.
s. d.
Halibut (cuts)2582 3115
Sole3462 6138
Turbot2701 6180
Brill3271 8196
Haddock2321 2198
Hake2561 3204
Smoked haddock2861 3228
Plaice3671 6244
Cod (section)2961 1252
Whiting215– 10258
Salmon (section)8473 –282
Eels7991 10436
Dried ling5601 –560
Mackerel515– 10618
Dried cod7501 –750
Kippered herring730– 9972
Herring709– 81062
Bloaters715– 81072
Red herrings1220– 81830
Salt herrings1129– 52712

Finally, the popularity or otherwise of any foodstuff necessarily depends upon its flavour. Fishes differ greatly in this respect. In many cases the flavour of a fish can be seriously impaired by an unsuitable method of cooking. A full-flavoured fish like the mackerel lends itself to a variety of methods of cooking, equally good results being obtained by baking, grilling, frying in fillets or boiling. The plaice, sole, ling, hake, mullet, and turbot are essentially fish for frying, while cod, haddock and whiting are best boiled. To prepare a fish for the table requires considerable skill, but it is an art that, once acquired, can be used to render even what are regarded as inferior varieties both wholesome and palatable. In this country, fishes have long been a neglected form of food. They have a high food value, they are easily digestible, and are cheap and plentiful.

It has been shown recently that edible fish contain vitamins. Vitamins are complex chemical compounds of hitherto unknown composition, and of little understood properties, that occur in minute quantities in a great variety of natural food stuffs. These vitamins appear to be essential to healthy animal existence. Without them, the body rapidly becomes attacked by certain diseases, e.g. rickets, beri-beri, scurvy, and unless this deficiency of the diet is corrected, death soon follows. Three different vitamins have been discovered, known as vitamins A, B, and C. Vitamin A is contained in the oily part of most fish, while Vitamin B is present in certain fish roes.