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  STATISTICAL 
  SURVEY 
  PROCEDURE 
  

  

  Whale 
  Products 
  — 
  Since 
  data 
  are 
  not 
  available 
  on 
  the 
  poundage 
  of 
  whales 
  taken, 
  statis- 
  

   tics 
  appearing 
  in 
  catch 
  tables 
  on 
  the 
  yield 
  of 
  these 
  mammals 
  represent 
  the 
  weight 
  of 
  products 
  

   produced 
  such 
  as 
  meal, 
  sperm 
  oil, 
  and 
  whale 
  oil. 
  The 
  values 
  shown 
  represent 
  the 
  amount 
  received 
  

   by 
  the 
  manufacturer 
  for 
  the 
  products. 
  

  

  Incidental 
  C 
  a 
  t 
  c 
  h 
  - 
  -The 
  term 
  "incidental 
  catch" 
  refers 
  to 
  the 
  catch 
  of 
  certain 
  species 
  by 
  

   a 
  type 
  of 
  gear 
  which 
  ordinarily 
  does 
  not 
  capture 
  such 
  species. 
  

  

  Percentages 
  — 
  Percentages 
  are 
  usually 
  shown 
  as 
  whole 
  numbers. 
  Fractions 
  of 
  percents 
  

   are 
  dropped 
  if 
  less 
  than 
  five-tenths, 
  and 
  the 
  percentage 
  is 
  raised 
  to 
  the 
  next 
  higher 
  integer 
  if 
  the 
  

   fraction 
  is 
  greater 
  than 
  five-tenths. 
  If 
  the 
  fraction 
  is 
  exactly 
  five-tenths, 
  add 
  integers 
  are 
  raised 
  

   to 
  the 
  next 
  even 
  figure 
  while 
  even 
  integers 
  remain 
  unchanged. 
  

  

  Converting 
  - 
  -Many 
  of 
  the 
  figures 
  shown 
  in 
  the 
  summary 
  tables 
  published 
  herewith 
  have 
  

   converted 
  to 
  thousands 
  of 
  pounds 
  or 
  thousands 
  of 
  dollars. 
  In 
  making 
  these 
  conversions 
  the 
  sum 
  

   of 
  the 
  items 
  in 
  a 
  table 
  is 
  raised 
  or 
  lowered 
  to 
  the 
  nearest 
  thousand 
  in 
  accordance 
  with 
  standard 
  

   statistical 
  procedures. 
  The 
  individual 
  items 
  are 
  adjusted 
  to 
  conform 
  to 
  the 
  total 
  thus 
  obtained. 
  

  

  Confidential 
  Data 
  --The 
  statistical 
  data 
  collected 
  by 
  the 
  Service 
  are 
  confidential, 
  and, 
  

   unless 
  specific 
  authorization 
  is 
  given, 
  are 
  not 
  released 
  in 
  a 
  manner 
  that 
  would 
  divulge 
  private 
  

   enterprise 
  . 
  

  

  CONVERSION 
  FACTORS 
  

  

  It 
  is 
  the 
  policy 
  of 
  the 
  Service 
  to 
  show 
  detailed 
  catch 
  figures 
  of 
  all 
  products 
  in 
  pounds 
  for 
  the 
  

   sake 
  of 
  uniformity 
  and 
  for 
  the 
  purposes 
  of 
  comparison. 
  This 
  represents 
  little 
  difficulty 
  in 
  the 
  

   case 
  of 
  fish, 
  since 
  in 
  very 
  rare 
  instances 
  are 
  fish 
  reported 
  in 
  units 
  of 
  measure 
  other 
  than 
  pounds. 
  

   For 
  shellfish, 
  however, 
  the 
  units 
  of 
  measure 
  may 
  be 
  bushels, 
  sacks, 
  barrels, 
  numbers, 
  gallons 
  

   of 
  meats, 
  etc. 
  So 
  many 
  units 
  make 
  standardization 
  difficult, 
  and 
  when 
  combined 
  with 
  the 
  wide 
  

   variation 
  in 
  the 
  requirements 
  or 
  definitions 
  of 
  some 
  of 
  these 
  units 
  in 
  the 
  various 
  States, 
  the 
  prob- 
  

   lem 
  becomes 
  even 
  more 
  complex. 
  

  

  All 
  univalve 
  and 
  bivalve 
  mollusks 
  (except 
  fresh-water 
  mussel 
  shells) 
  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 
  in 
  number 
  of 
  certain 
  other 
  shellfish, 
  such 
  as 
  

   crabs. 
  There 
  also 
  is 
  included 
  in 
  the 
  General 
  Review 
  section 
  of 
  this 
  report 
  a 
  table 
  containing 
  data 
  

   on 
  the 
  shell 
  weight 
  of 
  univalve 
  and 
  bivalve 
  mollusks 
  taken. 
  

  

  Oysters 
  - 
  -Probably 
  the 
  greatest 
  problem 
  in 
  the 
  presentation 
  of 
  fishery 
  statistics 
  in 
  uniform 
  

   units 
  of 
  measure 
  is 
  in 
  the 
  case 
  of 
  oysters. 
  Usually 
  the 
  production 
  of 
  oysters 
  on 
  the 
  Atlantic 
  and 
  

   Gulf 
  Coasts 
  is 
  reported 
  to 
  NMFS 
  personnel 
  in 
  bushels. 
  Prior 
  to 
  the 
  data 
  obtained 
  for 
  the 
  year 
  

   1930, 
  bushels 
  were 
  converted 
  to 
  pounds 
  of 
  meats 
  on 
  the 
  basis 
  of 
  a 
  uniform 
  yield 
  of 
  7 
  pounds 
  of 
  

   meats 
  to 
  the 
  bushel. 
  However, 
  it 
  was 
  found 
  that 
  there 
  was 
  considerable 
  variation 
  in 
  the 
  yield 
  of 
  

   oysters 
  per 
  bushel 
  particularly 
  in 
  Southern 
  States 
  where 
  the 
  yield 
  has 
  ranged 
  as 
  low 
  as 
  half 
  the 
  

   conversion 
  factor 
  used 
  prior 
  to 
  1930. 
  There 
  follows 
  a 
  table 
  which 
  gives 
  the 
  measures 
  used 
  for 
  

   oysters 
  in 
  the 
  various 
  States 
  and 
  the 
  average 
  yields 
  per 
  bushel. 
  The 
  statistical 
  tables 
  in 
  this 
  

   report 
  are 
  based 
  on 
  these 
  average 
  yields. 
  

  

  