548 U. S. BUREAU OF FISHERIES 
thousands place. If the number ends in an even 500, the thousands 
integer is raised or lowered to make it an even number. The indi- 
vidual items are changed to conform to the total thus obtained. 
Confidential data.—The statistical data collected by the Division are 
confidential and are not released except by approval of the Washington 
office. Statistics of production of wholesale and manufacturing firms 
are published only for commodities or geographical areas where the 
production of three or more concerns may be grouped. Every effort 
is made to publish only those figures which will not reveal individual 
enterprise. 
CONVERSION FACTORS 
It is the policy of the Bureau to show the detailed catch figures of 
all products in pounds for the sake of uniformity and for purposes of 
comparison. Following such a policy presents certain problems. In 
the case of fish there is little difficulty since in very rare instances are 
such products reported in units of measure other than pounds. For 
shellfish, however, the units of measure may be bushels, sacks, bar- 
rels, or thousands of shellfish, gallons of meats, ete. These many 
units make standardization difficult, but when coupled with the wide 
variation in the requirements or definition of some of these units in 
the various States the problem becomes even more complex. 
All bivalve mollusks are reported in pounds of meats in the detailed 
catch tables presented in this report. In addition, there are included 
supplementary tables for most of the sections, which give data on the 
production in bushels. These supplementary tables also give the 
production of certain other shellfish, such as crabs, in number. 
Oysters.—Probably the greatest problem in presentation of fishery 
statistics in uniform units of measure is in the case of oysters. Usu- 
ally the production of oysters on the Atlantic and Gulf coasts: is 
reported to Bureau agents in bushels; and prior to the data obtained 
for the year 1930 conversion from bushels to pounds of meats was 
effected on the basis of a uniform yield of 7 pounds ef meats to the 
bushel. However, more recent investigations have shown consider- 
able variation from this figure. There follows a table which gives the 
results of these studies of the measures used for oysters in the various 
States and of the average yields per bushel. This table presents the 
factors that have been used in the oyster statistics given in this report. 
Measures and yields of oysters 

Market oysters 



Capacity | variation f Wi Siul exer Ile ee 
State of State rom “1 | Yield per | Yield per 
bushel standard bushel State standard 
bushel bushel 
Pounds Pounds 
Cubic inches| Cubic inches| Percent of meats of meats 
IMassachusetts!::. Saas eels)  aeeeeen 2 V0 84m weeee ees fee .|||__ ._ Beeeas 6. 57 6. 57 
uhodeylsland-:. 9 2 Sea ee 2 ee eee OMS), Cl ||/Re  ae e e e 7.05 7.05 
Connecticuti® “oF 1 sees Tae Sea pees 2) D5OSS | RB Dan i]s tee eer es 7.70 7.70 
INeMmeOTke e350: fee 1 en BS a PROG Z| Ra Se eal as eS 7. 00 7.00 
ING WAICESCYe soo ae ae) 2; 257.3 +106. 9 +5.0 6.08 5.76 
Melawaret® cf eser tes eld eels AT epee 2257a8 +106. 9 +5.0 7. 00 6. 67 
Manylande= sss =. i. 22. Ss eee 2, 801.5 +651. 1 +30. 3 5. 98 4.59 
Warginians? 124: 23a $2. of) Pee a EET SE 3, 003. 4 +853. 0 +39. 7 6. 06 4. 34 
INOGonCarolings sae tee ae 2, 801.9 +651. 5 +30. 3 5. 52 4, 24 
Southi@arolinges sesso 2 aes Sees ee 4,071.5 | +1, 921.1 +89. 3 5. 87 3. 10 
Geonrigtsetwis Pier Sit Sed eke ee rey ed 5, 343.9 | +38, 1938.5 +148. 5 6. 21 2. 50 
ME OIG Bee eS ee ee ee ee 2 eae 3, 214.1 +1, 063. 7 +49. 4 5. 49 3. 67 
AA aang eres FES: EST eMC L ae 2, 826. 2 +675. 8 +31. 4 5.13 3.90 
IVISSSISSIO DP lee eg 2, 826. 2 +675. 8 +31. 4 4.95 3. 78 
MIOUISIATI A eee ae ere ee ee en My AED 2, 148. 4 —2:.0 =, 1 4.09 4.09 
Mexas ssf 20! Vek ge Pe ot eed eh es 2, 700. 0 +549. 6 +25. 6 5. 64 4.49 



