﻿154 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  practice. 
  Each 
  line 
  on 
  the 
  nieasuiing 
  stick 
  registers 
  7,000 
  shad 
  eggs. 
  

   The 
  number 
  of 
  eggs 
  in 
  a 
  liquid 
  pint 
  is 
  established 
  by 
  actual 
  count. 
  

   Those 
  which 
  are 
  very 
  young 
  or 
  have 
  been 
  lately 
  on 
  trays 
  are 
  not 
  of 
  

   normal 
  size 
  and 
  not 
  qualified 
  for 
  measurement. 
  The 
  eggs 
  are 
  at 
  rest 
  

   when 
  measured. 
  

  

  The 
  jar 
  contents 
  are 
  determined 
  by 
  placing 
  the 
  short 
  leg 
  of 
  the 
  

   measuring-stick 
  over 
  the 
  top, 
  with 
  the 
  other 
  pointing 
  downward 
  and 
  

   touching 
  the 
  side 
  of 
  the 
  jar. 
  The 
  number 
  is 
  indicated 
  on 
  the 
  scale 
  at 
  

   the 
  point 
  opposite 
  the 
  surface 
  of 
  the 
  bulk 
  of 
  the 
  eggs. 
  Scarcely 
  any 
  

   semi-buoyant 
  eggs 
  die, 
  under 
  proper 
  conditions, 
  after 
  hatching 
  out 
  has 
  

   commenced, 
  and 
  a 
  close 
  approximation 
  to 
  the 
  number 
  of 
  fry 
  may 
  be 
  

   obtained 
  from 
  the 
  last 
  measurement, 
  which 
  is 
  

   made 
  after 
  the 
  careful 
  removal 
  of 
  all 
  dead 
  eggs 
  

   and 
  the 
  bursting 
  forth 
  of 
  the 
  first 
  young. 
  

  

  FEEDING 
  AND 
  REARING. 
  

  

  The 
  young 
  shad 
  swims 
  vigorously, 
  by 
  rapid 
  

   and 
  continuous 
  vibration 
  of 
  the 
  tail, 
  from 
  the 
  

   moment 
  it 
  leaves 
  the 
  egg. 
  It 
  is 
  colorless, 
  trans- 
  

   parent, 
  and 
  gelatinous. 
  Several 
  hundred 
  in 
  a 
  

   dipper 
  are 
  scarcely 
  discernible. 
  It 
  has 
  a 
  rela- 
  

   tively 
  large 
  yolk-sac, 
  but 
  supports 
  it 
  with 
  ease 
  

   during 
  the 
  first 
  four 
  or 
  five 
  days 
  after 
  hatching, 
  

   the 
  small 
  quantity 
  remaining 
  after 
  this 
  time 
  not 
  

   being 
  visible 
  externally, 
  although 
  found 
  in 
  shad 
  

   fry 
  14 
  to 
  16 
  days 
  old. 
  Minute 
  conical 
  teeth 
  make 
  

   their 
  appearance 
  on 
  the 
  lower 
  jaws 
  and 
  in 
  the 
  

   pharynx 
  about 
  the 
  second 
  or 
  third 
  day 
  after 
  

   hatching. 
  The 
  jaws 
  at 
  three 
  months 
  are 
  arm^ed 
  

   with 
  teeth 
  slightly 
  curved. 
  

  

  Young 
  shad 
  feed 
  on 
  other 
  minute 
  organisms, 
  

   such 
  as 
  exceedingly 
  small 
  crustaceans. 
  Food 
  

   has 
  never 
  been 
  observed 
  in 
  the 
  alimentary 
  canal 
  

   until 
  ten 
  or 
  twelve 
  days 
  after 
  the 
  young 
  fish 
  had 
  

   left 
  the 
  egg. 
  At 
  about 
  the 
  middle 
  of 
  the 
  second 
  

   Application 
  of 
  a 
  measur- 
  week 
  considerable 
  may 
  be 
  seen, 
  but 
  the 
  intestine 
  

   ing 
  scale 
  to 
  a 
  jar 
  of 
  shad 
  jg 
  then 
  uot 
  often 
  very 
  densely 
  packed. 
  At 
  the 
  

   ®Sg8. 
  j^g.g 
  Qf 
  three 
  weeks 
  an 
  abundance 
  of 
  food 
  is 
  

  

  found. 
  They 
  have 
  been 
  known 
  at 
  this 
  early 
  age 
  to 
  eat 
  their 
  own 
  kind, 
  

   and 
  later 
  the 
  young 
  carp 
  and 
  salmon. 
  When 
  cold, 
  raw 
  winds 
  drive 
  

   the 
  crustaceans 
  into 
  deeper 
  water, 
  the 
  yomig 
  shad 
  follow 
  them, 
  and 
  

   ill 
  aquaria 
  they 
  take 
  Crustacea 
  freely. 
  lu 
  salt-water 
  aquaria 
  they 
  may 
  

   be 
  fed 
  upon 
  chopped 
  oysters 
  and 
  canned 
  herring-roe. 
  

  

  Experiments 
  with 
  young 
  shad 
  have 
  been 
  carried 
  on 
  for 
  several 
  years 
  

   at 
  Central 
  Station 
  in 
  salt-water 
  aquaria. 
  On 
  one 
  occasion 
  about 
  250 
  

   were 
  received 
  in 
  October, 
  at 
  which 
  time 
  they 
  were 
  about 
  five 
  months 
  

   old. 
  They 
  were 
  put 
  in 
  brackish 
  water, 
  specific 
  gravity 
  1.005, 
  which 
  

  

  