﻿136 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  adults. 
  It 
  lias 
  been 
  observed 
  by 
  Nortli 
  Carolina 
  porpoise 
  fisliennen 
  

   that 
  as 
  the 
  shad 
  swim 
  close 
  along 
  tbe 
  shore 
  the 
  porpoises 
  follow 
  and 
  

   feed 
  on 
  them 
  till 
  they 
  pass 
  into 
  fresh 
  water. 
  In 
  the 
  rivers 
  the 
  adult 
  

   shad 
  is 
  comparatively 
  free 
  from 
  enemies. 
  

  

  To 
  what 
  extent 
  the 
  pollution 
  of 
  the 
  waters 
  has 
  reduced 
  the 
  numbers 
  

   of 
  shad 
  is 
  not 
  known, 
  but 
  acids, 
  sawdust, 
  garbage, 
  oils, 
  gas 
  tar, 
  and 
  

   refuse 
  from 
  dye-works 
  all 
  tend 
  to 
  make 
  the 
  water 
  of 
  rivers 
  unsuitable 
  

   for 
  them. 
  

  

  FOOD. 
  

  

  After 
  entering 
  the 
  rivers, 
  the 
  shad 
  takes 
  but 
  little, 
  if 
  any, 
  food 
  

   previous 
  to 
  spawning, 
  but 
  after 
  casting 
  its 
  eggs 
  it 
  bites 
  at 
  flies 
  or 
  aiiy 
  

   small 
  shining 
  object, 
  and 
  has 
  been 
  known 
  to 
  take 
  the 
  artificial 
  fly. 
  

   The 
  mouth 
  of 
  the 
  adult 
  is 
  practically 
  toothless, 
  and 
  its 
  throat 
  contains 
  

   no 
  functionally 
  active 
  teeth. 
  The 
  water 
  which 
  passes 
  through 
  the 
  

   branchial 
  filter 
  — 
  the 
  gillrakers 
  — 
  is 
  deprived 
  of 
  the 
  small 
  animals 
  which 
  

   are 
  too 
  large 
  to 
  pass 
  through 
  its 
  meshes. 
  It 
  is 
  a 
  common 
  remark 
  with 
  

   fishermen 
  and 
  others 
  that 
  food 
  is 
  rarely 
  found 
  in 
  the 
  stomach 
  of 
  the 
  

   adult 
  shad 
  in 
  fresh 
  water, 
  but 
  examinations 
  have 
  shown 
  that 
  the 
  shad 
  

   does, 
  in 
  some 
  instances, 
  eat 
  small 
  Crustacea, 
  insects, 
  etc. 
  The 
  only 
  

   substance 
  commonly 
  found 
  in 
  its 
  stomach 
  in 
  fresh 
  water 
  has 
  the 
  

   appearance 
  of 
  black 
  mud. 
  It 
  is 
  held 
  by 
  some 
  that 
  the 
  shad 
  swims 
  

   witli 
  its 
  mouth 
  oijen 
  and 
  may 
  unintentionally 
  swallow 
  the 
  small 
  organ- 
  

   isms 
  found 
  in 
  its 
  stomach 
  under 
  such 
  circumstances, 
  but 
  as 
  far 
  as 
  

   observation 
  of 
  fish 
  in 
  aquaria 
  and 
  experiences 
  of 
  net 
  fishermen 
  go, 
  the 
  

   shad 
  does 
  not 
  swim 
  with 
  its 
  mouth 
  open. 
  

  

  NATURAL 
  SPAWNING. 
  

  

  Shad 
  are 
  liable 
  to 
  be 
  ripe 
  anywhere 
  above 
  brackish 
  water, 
  and 
  under 
  

   favorable 
  temperature 
  conditions 
  spawn 
  wherever 
  they 
  happen 
  to 
  be, 
  

   but 
  in 
  some 
  river 
  basins 
  they 
  exhibit 
  a 
  well 
  defined 
  choice 
  of 
  spawning- 
  

   places, 
  preferring 
  localities 
  below 
  the 
  mouths 
  of 
  creeks, 
  where 
  the 
  

   warmer 
  water 
  of 
  creeks 
  mingles 
  with 
  the 
  colder 
  channel 
  water. 
  The 
  

   shad 
  lays 
  its 
  eggs 
  during 
  the 
  highest 
  daily 
  average 
  temperature, 
  a 
  con- 
  

   dition 
  realized 
  about 
  sunset, 
  when 
  the 
  warmer 
  shoal 
  water 
  commingles 
  

   with 
  the 
  colder 
  channel 
  water, 
  establishing 
  a 
  balance. 
  The 
  principal 
  

   spawning 
  occurs 
  from 
  5 
  p. 
  m. 
  to 
  10 
  p. 
  m. 
  Observations 
  on 
  the 
  Potomac 
  

   River 
  show 
  that 
  of 
  the 
  eggs 
  from 
  shad 
  caught 
  in 
  a 
  seine 
  only 
  11 
  per 
  

   cent 
  were 
  taken 
  between 
  midnight 
  and 
  noon, 
  the 
  j)ercentage 
  in 
  the 
  

   morning 
  being 
  14 
  one 
  year 
  and 
  8 
  another. 
  

  

  The 
  eggs 
  in 
  the 
  ovaries 
  remain 
  in 
  a 
  compact 
  mass 
  until 
  they 
  ripen, 
  

   at 
  first 
  occupying 
  but 
  a 
  small 
  space, 
  but 
  gradually 
  increasing 
  until 
  

   they 
  distend 
  the 
  whole 
  abdomen, 
  the 
  average 
  weight 
  of 
  the 
  ovaries 
  being 
  

   about 
  13 
  ounces. 
  Close 
  examination 
  at 
  the 
  approach 
  of 
  the 
  spawning 
  

   time 
  will 
  disclose 
  large 
  maturing 
  eggs 
  of 
  rather 
  uniform 
  size 
  and 
  others 
  

   smaller 
  and 
  of 
  variable 
  size. 
  Whether 
  the 
  latter 
  are 
  the 
  forming 
  eggs 
  

   for 
  the 
  next 
  year, 
  for 
  two 
  or 
  three 
  succeding 
  years, 
  or 
  for 
  the 
  lifetime 
  of 
  

   the 
  fish 
  has 
  not 
  been 
  determined, 
  nor 
  is 
  it 
  known 
  whether 
  shad 
  spawn 
  

   every 
  year. 
  The 
  small 
  and 
  shrunken 
  ovaries 
  of 
  a 
  spent 
  fish 
  are 
  still 
  

  

  