Introduction
Measures of weight and volume
Densities and stowage rates
Physical composition of cod
Yields

## Introduction

This leaflet includes such miscellaneous information as definitions of some common units of measurement in the fishing industry, densities and stowage factors for a number of forms of fish, fish products and ice, and some conversion factors for yields of fish products from raw material.

Many of the figures given are approximate, since stowage rates and yields, for instance, depend upon, among other things, size and condition of the fish and the method of processing. In addition, information on many species and products is missing from this leaflet, either because Torry has no figures, or because the figures available are so unreliable that to record them would be misleading.

## Measures of weight and volume

Units of measurement peculiar to the fishing industry are given in detail on the next page, but first it is necessary to set out the tables of British weights and measures that form the basis of commercial transactions:

 Avoirdupois Weight 16 ounces = 1 pound 14 pounds = 1 stone 28 pounds = 1 quarter 112 pounds = 1 hundredweight (cwt) 20 cwts = 1 ton

 Capacity - Dry Measure 20 ounces = 1 pint 2 pints = 1 quart 4 quarts = 1 gallon 2 gallons = 1 peck 4 pecks = 1 bushel 8 bushels = 1 quarter

The following are some of the more common units of weight and volume in general use in the fish trade:

Kit: (measure of weight) -

1 kit = 10 stones = 140 pounds
16 kits = 1 ton
The 10-stone kit is a measure of weight in regular use at the quayside in Hull, Grimsby, Fleetwood and Lowestoft for the sale of white fish. Milford Haven uses 8- and 12-stone kits in addition to a 10-stone one for some species.

The term ‘kit’ is also applied to other measures of weight ranging from 60 pounds to 12 stones that are used occasionally for certain species at some smaller ports, particularly in the West of England.

Cran: (measure of volume) -

1 cran = 37 gallons = 6·03 cubic feet
Herring are customarily sold in Britain by the cran. Under the Herring Industry Board’s minimum prices rules, and under Weights and Measures Regulations, all herring not sold by the cran must be sold by weight. A cran contains on average roughly 1,200 herrings, but this figure can vary widely with season and ground from 700 to 2,500 herrings for different fisheries. A cran measure is approximately equivalent to 28 stones of herring.

As used at ports for the landing of herring.
4 baskets = 1 cran (1 basket holds approx. 7 stones herring)
Box:

The box is used both as a measure of weight and as a measure of volume: at quayside sale it may contain anything from 5 to 10 stones of white fish at different ports. Aberdeen, for example, weighs its fish into 8-stone lots in boxes, whereas Granton lands fish unweighed in boxes said to contain approximately 6 stones. Most British ports now define the amount of fish being sold in boxes by declaring the contents either as a measured or as an estimated weight in stones and pounds.

Herring are often sold in boxes that reputedly contain a declared fraction of the cran unit of measurement. Any such sale must, however, be a sale by weight. Usual sizes of box are those that reputedly contain one-quarter or one-sixth of a cran; less common are boxes reputedly holding one-third or one-fifth of a cran.

Barrel: (measure of volume) -

Statutory obligation to make barrels in Scotland to a prescribed size was removed in 1963, and herring barrels can now be of any size: it is likely however that barrels of the following size will continue to be used for some time:

1 herring barrel = 26 gallons
herring barrel = 13 gallons
Used as a measure for pickle-salted herrings, the contents of a barrel will weigh about 320 pounds, and for Scotch cured herring will consist of about 700 to 1,100 fish depending on the selection. Roughly two-elevenths of the weight of the contents (58 pounds) is accounted for by salt and pickle, and nine-elevenths is fish (262 pounds).

The usual size of foreign barrel that is sometimes used in Britain holds about 100 kilos.

Bag: (measure of weight) -

For the sale of cockles and mussels in shell, a bag usually contains about 1 cwt of shellfish at most ports, but the contents can range from 7 to 10 stones depending upon the port and on whether or not the contents are weighed.

Bushel: (measure of volume) -

When used as a measure for the sale of sprats, a bushel contains about 56 pounds of fish.

Peck: (measure of volume) -

When used as a measure for shrimps, a peck contains about 10 to 14 pounds.

## Densities and stowage rates

 1. Fresh Fish Density Stowage Rate Chilled fresh fish muscle 65·8 lb/ft3 Whole fresh herring in bulk 58·2 “ 38·5 ft3/ton Whole fresh mackerel in bulk 50·0 “ 45 “ Whole fresh sprats in bulk 53·2 “ 42 “ Whole fresh capelin in bulk 62·5 lb/ft3 36 ft3/ton Whole fresh cod in bulk gutted 57·5 “ 39 “ (variable - depends on size of fish) Whole gutted fresh cod in bulk with ice ( fish to ice by weight) 49·5 lb mixture/ft3 45 ft3/ton mixture 33 lb fish/ft3 68 ft3/ton fish = 4·25 ft3/kit Whole gutted fresh cod in bulk in ice (ratio as above) but including allowance for fishroom structure 32 lb fish/ft3 70 ft3/ton fish = 4·37 ft3/kit Whole gutted fresh cod stowed in single layers on ice on shelves 9 in. apart (including allowance for structure) 14 lb fish/ft3 160 ft3/ton fish = 10 ft3/kit Whole gutted fresh cod boxed in ice ( fish to ice by weight, and including allowance for space occupied by boxes in block stowage) 23 lb fish/ft3 96 ft3/ton fish = 6 ft3/kit * * (figure varies from 5·3 to 6·4 ft3/kit depending on ratio of the effective volume to external volume of box) Fresh fillets in bulk 60 lb/ft3 37 ft3/ton Fresh fillets, boxed with ice (enough ice for normal inland journey, and including allowance for box) 30 lb fish/ft3 75 ft3/ton fish Fresh fish livers, roes or milts in bulk 62·5 lb/ft3 36 ft3/ton 2. Frozen Fish Frozen whole gutted cod in large blocks - weight of fish within dimensions of the block 40 lb/ft3 (fish very loosely packed in block) 55 lb/ft3 (very compact block) avg. 48 lb/ft3 Frozen whole gutted cod in large blocks, including allowance for supporting structure, access, etc. 31 lb/ft3 72 ft3/ton fish = 4·5 ft3/kit Frozen fillets in large blocks 55 to 60 lb/ft3 37 to 40 ft3/ton Frozen fillets in large blocks, including allowance for packaging, structure, access, etc. 40 to 50 lb/ft3 45 to 56 ft3/ton Frozen fillets or steaks in catering packs in master carton 50 to 60 lb/ft3 37 to 45 ft3/ton Frozen fillets in consumer packs in master carton, with allowance for pallets, access, etc. 25 lb/ft3 90 ft3/ton Frozen fish sticks in retail packs 25 to 30 lb/ft3 75 to 90 ft3/ton Frozen whole gutted cod, stowed as single fish 25 to 30 lb/ft3 75 to 90 ft3/ton Frozen whole gutted halibut: in wooden boxes 30 to 35 lb/ft3 65 to 75 ft3/ton stowed loose 38 lb/ft3 59 ft3/ton Frozen whole salmon: stowed loose 33 to 35 lb/ft3 65 to 68 ft3/ton in wooden boxes 90 to 95 ft3/ton Frozen shelled shrimp in blocks 45 to 55 lb/ft3 40 to 50 ft3/ton Frozen shelled shrimp in blocks, including allowance for packing structure, etc. 37 to 45 lb/ft3 50 to 60 ft3/ton Frozen breaded shrimp in consumer packs in master carton 25 to 30 lb/ft3 75 to 90 ft3/ton 3. Other Fish Products Fish liver oil 58 lb/ft3 39 ft3/ton Fish meal, loose ground 39 lb/ft3 58 ft3/ton Fish meal unground 30 lb/ft3 75 ft3/ton Fish meal, bagged in 1 cwt bags stacked 10 high 70 ft3/ton Crawfish, canned in cartons approx. 100 ft3/ton Dried cod in hundredweight bales 37·5 lb/ft3 60 ft3/ton Dried fish in wooden boxes (181 lbs gross wt) 100 ft3/ton Salmon salted in barrels 45 to 50 ft3/ton Kippers in 1 stone wooden boxes 31 lb/ft3 72 ft3/ton (approx. 24 pairs of average kippers = 1 stone) Salt fish: in bags (218 lbs gross wt) 125 ft3/ton in wooden boxes (185 lbs gross wt) 50 ft3/ton in casks (720 lbs gross wt) 45 ft3/ton in kegs (90 lbs gross wt) 55 ft3/ton 4. Ice Solid ice at 32° F 57·24 lb/ft3 Crushed block ice 40 lb/ft3 56 ft3/ton Flake ice 30 lb/ft3 75 ft3/ton Tube ice 34 lb/ft3 66 ft3/ton

## Physical composition of cod

Approximate weights of component parts of the body are given as percentages both of the whole ungutted fish and of the gutted fish. Weights of liver, guts, roe, etc., can fluctuate enormously with season, ground, condition of fish and so on; these figures can do no more than provide a very rough guide to yields after say heading, or heading and gutting, etc.

 Component Percentage Percentage whole weight gutted weight range avg. range avg. Head 21% 25% Guts 5-8% 7% 6-9% 8% Liver 2-7% 5% 3-8% 5% - removed Roe 1-7% 4% 1-8% 5% Backbone, etc. 14% 17% Fins and lugs 10% 12% Skin 3% 4% Fillet, skinned 36% 42% 100% 100% + 18% guts and liver

## Yields

The following tables give figures for converting weight of whole fish to weight of fish product. The weight of whole fish is taken to be the weight as landed from iced stowage, that is gutted and with heads on, except for the following species, which are normally landed whole ungutted: herring, sprat, mackerel, pilchard, redfish, salmon, dogfish. It is assumed that filleting and processing are carried out to a good commercial standard.

1. Wet fillets:

To convert net landed weight of whole fish to equivalent weight as fillets:

 Species Multiply landed weight by Fillets without skin Fillets with skin Cod 0·42 0·47 Codling 0·40 0·44 Haddock (large) 0·42 0·47 (small) 0·40 0·43 Whiting 0·38 0·44 (block fillets) Hake 0·50 0·55 Ling 0·48 0·55 Plaice 0·35 0·52 Lemon sole 0·42 0·58 Catfish 0·35 Redfish 0·30 0·35 White fish generally 0·43 0·47 Herring: immature 0·57 spent 0·55 up to ripe 0·58 to ripe 0·54 to + ripe 0·51 ripe 0·47 Herring generally 0·53

2. Wet steaks:

To convert net landed weight of whole fish to equivalent as steaks:

 Species Multiply landed weight by Salmon 0·60 to 0·65 Halibut 0·70 to 0·75

3. Smoked fish:

To convert net landed weight of whole fish to weight of smoked product:

 Smoked product Multiply landed weight by Cod fillet 0·32 to 0·35 Finnan haddock 0·50 to 0·60 Golden cutlet 0·25 to 0·30 Smokie 0·45 to 0·50 Kipper 0·65 to 0·70 Bloater 0·68 to 0·80 Red herring 0·60 to 0·62 Salmon sides 0·45 to 0·60 (depends very much on weight of roe in whole fish, and condition of fish). Mackerel, hot smoked whole gutted 0·60 Eel, ditto 0·65 to 0·75

4. Salt fish:

To convert net landed weight of whole fish to equivalent weight of salted product:

 Salted product Multiply landed weight by Dried salted split cod: light cure 0·24 medium cure 0·26 heavy cure 0·34 Wet (Green) salted split cod: light cure 0·60 medium cure 0·56 heavy cure 0·50

Note. - Above figures are based on Canadian products; Norway quotes figures from 0·37 to 0·43 for salted split cod yield, but amount of drying not known.

 Herring: pickle cured 0·79 to 0·88 (depends on ratio fish to salt in barrel).

5. Frozen fish:

To convert from net landed weight of whole fish to equivalent weight of frozen product:

 Frozen product Multiply landed weight by Skinless cod fillet 0·42 (Note: loss of weight during cold storage or during thawing is ignored). Headless gutted cod 0·75 Whole fish, all spp. 1·00 Salmon steaks 0·65

Typical yield from a frozen, headless, gutted halibut cut up for steaks is as follows:

 Steaks 74·5% Bellies 7·25% Tail chunks 1·25% 83%

 Sawdust 4·5% Trimmings 6·75% (nape, tail fin, etc.). Unaccounted for 5·75% 100%

Loss as sawdust during cutting up of frozen fillets of cod for fish sticks is about 8 to 12% of weight of fillet.

6. By-products:

To convert weight of white fish raw material to weight of fish meal, multiply by 0·21.

7. Edible portion of miscellaneous species:

For those species for which the equivalent weight as fillets is either not available or not appropriate, conversion factors are given for the weight of the edible portion from the landed weight of the fish.

 Species Multiply landed weight by Salmon 0·64 Sea trout 0·63 Brown trout 0·68 Eel 0·50 to 0·60 Perch 0·33 Pike 0·43 Angler 0·20 to 0·25 (meat only) 0·33 (skinned tail) Gurnard 0·40 Skate, ray, as wings 0·45 Dogfish 0·35 to 0·45 Conger 0·50 Crab 0·27 to 0·36 Lobster 0·44 Norway lobster whole 0·20 to 0·27 unshelled tails 0·54 to 0·61 Shrimp, brown 0·30 to 0·40 Prawn 0·4 Oyster 0·11 to 0·17 Cockle 0·08 to 0·15 Winkle 0·23 Scallop 0·10 to 0·18 Mussel 0·08 to 0·20 Whelk 0·42