﻿[11] 
  A 
  SYSTEM 
  OF 
  OYSTER 
  CULTURE. 
  391 
  

  

  allowed 
  it 
  to 
  remain 
  on 
  shore, 
  where 
  it 
  would 
  at 
  least 
  not 
  have 
  been 
  

   altogether 
  useless. 
  h\ 
  many 
  cases 
  it 
  is 
  necessary 
  before 
  planting 
  that 
  

   the 
  bottom 
  be 
  prepared 
  by 
  dumping 
  gravelly, 
  firm 
  loam 
  over 
  it 
  before 
  

   attempting 
  to 
  plant 
  either 
  oysters 
  or 
  shells 
  on 
  it, 
  so 
  that 
  it 
  may 
  be 
  firm 
  

   enough 
  for 
  the 
  purpose. 
  In 
  other 
  cases 
  dredging 
  might 
  be 
  resorted 
  to 
  

   with 
  advantage, 
  but 
  that 
  would 
  depend 
  upon 
  circumstances; 
  whether, 
  

   in 
  fact, 
  it 
  could 
  be 
  done 
  at 
  a 
  justifiable 
  cost. 
  

  

  23. 
  Spatting 
  in 
  narrow 
  channels. 
  — 
  Another 
  remarkable 
  combination 
  of 
  

   conditions 
  under 
  which 
  a 
  fall 
  of 
  spat 
  occurs 
  may 
  be 
  here 
  cited 
  in 
  partial 
  

   illustration 
  of 
  the 
  system 
  of 
  spat-culture 
  to 
  be 
  developed 
  in 
  the 
  sequel. 
  

   At 
  Wood's 
  Holl, 
  Mass., 
  Mr. 
  J. 
  S. 
  Fay 
  some 
  years 
  ago 
  planted 
  some 
  

   oysters 
  in 
  almost 
  land-locked 
  ponds 
  owned 
  by 
  him, 
  and 
  in 
  which 
  the 
  

   density 
  of 
  the 
  water 
  ranges 
  from 
  1.012 
  to 
  1.020. 
  An 
  outlet 
  from 
  these 
  

   ponds 
  consists 
  of 
  a 
  little 
  water-course 
  which 
  is 
  not 
  much 
  over 
  a 
  foot 
  in 
  

   width 
  and 
  6 
  to 
  8 
  inches 
  deep 
  at 
  any 
  part 
  of 
  its 
  extent. 
  In 
  the 
  bottom 
  of 
  

   this 
  water-course 
  there 
  are 
  a 
  great 
  many 
  loose 
  stones 
  and 
  pebbles, 
  and 
  

   upou 
  these 
  oyster 
  fry 
  has 
  adhered 
  in 
  considerable 
  numbers. 
  In 
  this 
  case 
  

   what 
  would 
  at 
  first 
  appear 
  to 
  be 
  very 
  unfavorable 
  conditions 
  for 
  the 
  

   adhesion 
  and 
  development 
  of 
  oyster 
  fry 
  are, 
  on 
  the 
  contrary, 
  found 
  to 
  be 
  

   quite 
  favorable. 
  

  

  24. 
  Critical 
  periods 
  during 
  the 
  spawning 
  season. 
  — 
  There 
  are 
  critical 
  pe- 
  

   riods 
  or 
  crises 
  during 
  the 
  spawning 
  period 
  when 
  the 
  larger 
  proportion 
  

   of 
  the 
  spatting 
  of 
  one 
  season 
  occurs. 
  Somewhat 
  prolonged 
  observation 
  

   indicates, 
  as 
  far 
  as 
  my 
  personal 
  experience 
  goes, 
  that 
  these 
  crises 
  occur 
  

   during 
  the 
  latter 
  part 
  of 
  July 
  and 
  early 
  part 
  of 
  August. 
  According 
  to 
  

   the 
  observations 
  of 
  Brooks 
  and 
  Winslow 
  the 
  critical 
  period 
  when 
  the 
  

   greatest 
  amount 
  of 
  spat 
  falls 
  is 
  somewhat 
  earlier 
  farther 
  south, 
  perhaps 
  

   a 
  week 
  or 
  ten 
  days. 
  In 
  order 
  to 
  get 
  the 
  best 
  results 
  from 
  the 
  use 
  of 
  

   collectors 
  of 
  any 
  form, 
  it 
  is 
  therefore 
  desirable 
  that 
  the 
  cultch 
  should 
  

   be 
  exposed 
  to 
  the 
  fry 
  at 
  about 
  or 
  just 
  before 
  the 
  time 
  mentioned, 
  other- 
  

   wise 
  the 
  best 
  portion 
  of 
  the 
  season 
  will 
  be 
  lost 
  to 
  the 
  propagator. 
  An- 
  

   other 
  reason 
  why 
  the 
  cultch 
  should 
  be 
  put 
  down 
  during 
  or 
  immediately 
  

   preceding 
  these 
  critical 
  periods 
  is 
  that 
  the 
  accumulation 
  of 
  slime, 
  diatoms, 
  

   and 
  sediment 
  on 
  the 
  cultch 
  is 
  avoided 
  during 
  the 
  most 
  important 
  part 
  

   of 
  the 
  spatting 
  period. 
  

  

  The 
  accumulations 
  of 
  diatoms 
  on 
  the 
  collectors 
  are 
  especially 
  nox- 
  

   ious 
  and 
  hurtful 
  to 
  the 
  recently 
  fixed 
  fry, 
  since, 
  together 
  with 
  the 
  hordes 
  

   of 
  microscopical, 
  boat-shaped 
  organisms 
  known 
  as 
  diatoms, 
  there 
  rap- 
  

   idly 
  develops 
  a 
  slimy, 
  transparent 
  pellicle 
  on 
  recently 
  submerged 
  ob- 
  

   jects 
  which 
  soon 
  reaches 
  a 
  thickness 
  of 
  at 
  least 
  one-sixteenth 
  of 
  an 
  iuch. 
  

   This 
  pellicle 
  is 
  sometimes 
  quite 
  clear 
  and 
  transparent, 
  like 
  the 
  white 
  of 
  

   an 
  egg, 
  and 
  contains 
  besides 
  vast 
  numbers 
  of 
  frustules 
  of 
  diatoms 
  in- 
  

   numerable 
  multitudes 
  of 
  still 
  more 
  minute 
  organisms 
  resembling 
  Bac- 
  

   teria. 
  The 
  accumulation 
  of 
  this 
  pellicle 
  is 
  usually 
  only 
  a 
  matter 
  of 
  a 
  

   few 
  days, 
  and 
  is 
  probably 
  more 
  hurtful 
  to 
  the 
  very 
  early 
  stages 
  of 
  the 
  

   oyster 
  than 
  all 
  of 
  its 
  other 
  enemies 
  combined. 
  

  

  