﻿332 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  in 
  the 
  pond 
  will 
  be 
  lower 
  than 
  il 
  in 
  the 
  open 
  water, 
  and 
  under 
  those 
  circumstances 
  

   there 
  will 
  be 
  an 
  inflow 
  of 
  sea 
  water 
  into 
  the 
  pond 
  through 
  the 
  diaphragm 
  instead 
  of 
  

   an 
  outflow, 
  as 
  is 
  the 
  condition 
  of 
  the 
  water 
  level 
  during 
  ebb 
  tide. 
  Under 
  such 
  condi- 
  

   tions 
  there 
  will 
  be 
  four 
  alternating 
  periods 
  during 
  every 
  twenty-four 
  hours 
  of 
  inflow 
  

   and 
  outflow, 
  lasting, 
  we 
  will 
  say, 
  four 
  hours 
  each, 
  not 
  reckoning 
  the 
  nearly 
  stationary 
  

   intervals 
  between 
  tides 
  or 
  during 
  slack 
  water. 
  This 
  almost 
  constant 
  partial 
  renewal 
  

   of 
  the 
  water 
  will 
  unquestionably 
  maintain 
  the 
  water 
  inclosed 
  in 
  the 
  pond 
  or 
  ponds 
  

   by 
  means 
  of 
  diaphragms 
  in 
  a 
  condition 
  fitted 
  to 
  support 
  oysters 
  colonized 
  therein, 
  

   provided 
  its 
  density 
  is 
  not 
  too 
  great 
  or 
  too 
  slight, 
  and 
  if 
  there 
  is 
  also 
  some 
  micro- 
  

   scopic 
  vegetation 
  present. 
  

  

  It 
  will 
  be 
  readily 
  understood 
  from 
  the 
  preceding 
  description 
  how 
  it 
  is 
  intended 
  

   that 
  the 
  apparatus 
  is 
  to 
  be 
  operated. 
  The 
  figures 
  also 
  give 
  a 
  very 
  good 
  idea 
  of 
  how 
  

   the 
  diaphragm 
  and 
  trunk 
  are 
  to 
  be 
  constructed, 
  the 
  first 
  four 
  figures 
  being 
  drawn 
  

   to 
  a 
  common 
  scale 
  of 
  1 
  inch 
  to 
  3 
  feet.* 
  

  

  • 
  The 
  water 
  iu 
  the 
  pond 
  remained 
  at 
  about 
  the 
  same 
  density 
  and 
  tem- 
  

   perature 
  as 
  that 
  iu 
  the 
  open 
  bay 
  and 
  soon 
  developed 
  a 
  greater 
  abun- 
  

   dance 
  of 
  food 
  organisms, 
  both 
  plants 
  and 
  animals. 
  Artificially 
  fertilized 
  

   ova 
  were 
  placed 
  iu 
  the 
  jjond 
  at 
  intervals 
  during 
  the 
  spawning 
  season, 
  

   and 
  forty-six 
  days 
  after 
  the 
  beginning 
  of 
  the 
  experiment 
  young 
  spat 
  

   from 
  one-fourth 
  to 
  three-fourths 
  of 
  an 
  inch 
  long 
  were 
  found 
  attached 
  

   to 
  the 
  bunches 
  of 
  shells 
  which 
  had 
  been 
  hung 
  upon 
  stakes 
  to 
  serve 
  as 
  

   collectors. 
  Great 
  difficulty 
  was 
  experienced 
  from 
  sedimentation. 
  The 
  

   experiment 
  demonstrated 
  that 
  spat 
  could 
  be 
  raised 
  in 
  ponds 
  from 
  

   artificially 
  fertilized 
  eggs 
  and 
  that 
  it 
  would 
  grow 
  as 
  rapidly 
  as 
  the 
  spat 
  

   reared 
  in 
  the 
  o] 
  en 
  bay. 
  As 
  the 
  conditions 
  are 
  stated 
  by 
  Dr. 
  Ryder, 
  it 
  

   appears 
  probable 
  that 
  equally 
  good 
  or 
  better 
  results 
  might 
  have 
  been 
  

   attained 
  with 
  less 
  labor 
  by 
  placing 
  a 
  quantity 
  of 
  spawning 
  oysters 
  in 
  

   the 
  x>ond. 
  

  

  Not 
  only 
  would 
  there 
  be 
  a 
  saving 
  of 
  labor 
  in 
  the 
  direct 
  use 
  of 
  the 
  

   spawning 
  oysters, 
  but 
  there 
  would 
  also 
  be 
  no 
  necessity 
  for 
  the 
  sacrifice 
  

   of 
  the 
  parents, 
  as 
  must 
  be 
  done 
  under 
  the 
  method 
  of 
  artificial 
  fertiliza- 
  

   tion. 
  The 
  increase 
  in 
  the 
  size 
  of 
  the 
  spawners 
  under 
  the 
  favorable 
  

   conditions 
  of 
  growth 
  would 
  probably 
  go 
  far 
  toward 
  the 
  payment 
  of 
  

   expenses. 
  

  

  The 
  method 
  which 
  promises 
  the 
  best 
  results 
  is 
  that 
  in 
  which 
  the 
  eggs 
  

   are 
  deposited 
  in 
  the 
  pond 
  within 
  from 
  three 
  to 
  five 
  hours 
  after 
  fertili- 
  

   zation. 
  There 
  is 
  apparentlj^ 
  nothing 
  to 
  be 
  gained 
  in 
  holding 
  the 
  eggs 
  

   a 
  longer 
  time, 
  the 
  chief 
  gain 
  of 
  the 
  culturist 
  being 
  not 
  in 
  the 
  protection 
  

   of 
  the 
  embryo, 
  but 
  in 
  the 
  increase 
  of 
  the 
  proportion 
  of 
  eggs 
  fertilized. 
  

  

  The 
  method 
  of 
  fertilization 
  used 
  by 
  Dr. 
  Eyder 
  was 
  as 
  follows 
  : 
  

  

  The 
  method 
  formerlj" 
  used 
  was 
  to 
  first 
  learn 
  the 
  sex 
  of 
  a 
  number 
  of 
  adult 
  oysters 
  

   with 
  the 
  microscope, 
  then 
  cut 
  out 
  the 
  generative 
  glands 
  with 
  their 
  products 
  and 
  

   chop 
  up 
  those 
  of 
  different 
  sexes 
  separately 
  in 
  small 
  dishes 
  with 
  sea 
  water. 
  This 
  

   system 
  we 
  may 
  now 
  say 
  is 
  barbarous, 
  because 
  it 
  is 
  crude. 
  Large 
  numbers 
  of 
  eggs 
  are 
  

   destroyed 
  by 
  crushing, 
  or 
  are 
  injured 
  by 
  the 
  rough 
  usage 
  to 
  which 
  they 
  are 
  subjected, 
  

   and, 
  besides, 
  there 
  is 
  no 
  assurance 
  that 
  the 
  eggs 
  or 
  milt 
  operated 
  with 
  are 
  quite 
  

   mature. 
  It 
  is 
  also 
  troublesome 
  to 
  free 
  the 
  generative 
  gland 
  from 
  fragments 
  of 
  the 
  

   liver, 
  which 
  help 
  to 
  pollute 
  the 
  water 
  in 
  the 
  incubating 
  vessels 
  with 
  putrescible 
  

  

  *BuU, 
  U. 
  S. 
  F. 
  C. 
  1884, 
  pp. 
  19, 
  21, 
  22, 
  23. 
  

  

  