﻿MANUAL 
  OF 
  FISH-CULTURE. 
  137 
  

  

  found 
  fall 
  of 
  these 
  eggs 
  of 
  different 
  sizes. 
  Shortly 
  before 
  spawning, 
  

   transparent 
  eggs 
  of 
  large 
  size, 
  contrasting 
  strongly 
  with 
  the 
  opaqne 
  

   golden 
  hue 
  of 
  less 
  mature 
  ones, 
  will 
  be 
  found 
  scattered 
  through 
  the 
  still 
  

   compact 
  ovarian 
  mass, 
  and 
  becoming 
  more 
  and 
  more 
  numerous, 
  the 
  

   ovaries 
  disintegrate, 
  the 
  eggs 
  fall 
  apart, 
  and 
  extrusion 
  begins, 
  a 
  liquid 
  

   stream 
  of 
  eggs 
  and 
  mncus 
  flowing 
  from 
  the 
  oviduct 
  on 
  the 
  slightest 
  

   pressure 
  of 
  the 
  abdomen. 
  

  

  Freshly 
  dei)Osited 
  shad 
  eggs 
  are 
  of 
  a 
  pale 
  amber 
  or 
  pink 
  color, 
  and 
  

   are 
  transparent. 
  They 
  are 
  about 
  j-^- 
  inch 
  in 
  diameter 
  and 
  somewhat 
  

   flattened 
  and 
  irregularly 
  rounded 
  in 
  form. 
  Tlie 
  egg 
  membrane 
  is 
  much 
  

   wrinkled 
  and 
  lies 
  in 
  close 
  contact 
  with 
  the 
  contained 
  vitellus. 
  Imme- 
  

   diately' 
  after 
  fertilization 
  the 
  egg 
  becomes 
  spherical 
  through 
  the 
  absorp- 
  

   tion 
  of 
  water 
  and 
  api)arently 
  gains 
  very 
  much 
  in 
  bulk, 
  measuring 
  from 
  

   ^ 
  to 
  ^ 
  inch 
  in 
  diameter; 
  but 
  this 
  gain 
  is 
  only 
  the 
  distended 
  egg 
  mem- 
  

   brane, 
  the 
  vitellus 
  or 
  true 
  germinal 
  and 
  nutritive 
  portion 
  not 
  having 
  

   increased. 
  The 
  vitellus 
  is 
  heavier 
  than 
  water, 
  and 
  a 
  large 
  space 
  tilled 
  

   with 
  fluid 
  now 
  exists 
  between 
  it 
  and 
  the 
  membrane, 
  the 
  vitellus 
  rolling 
  

   about 
  and 
  changing 
  its 
  position 
  as 
  the 
  position 
  of 
  the 
  egg 
  membrane 
  is 
  

   altered. 
  Xo 
  adhesive 
  material 
  is 
  found 
  on 
  the 
  outside 
  of 
  the 
  membrane, 
  

   though 
  when 
  first 
  extruded 
  the 
  eggs 
  are 
  covered 
  with 
  a 
  somewhat 
  sticky 
  

   ovarian 
  mucus. 
  

  

  In 
  a 
  state 
  of 
  nature 
  the 
  shad 
  deposits 
  its 
  eggs 
  loosely 
  in 
  the 
  rivers 
  

   without 
  building 
  a 
  nest, 
  the 
  two 
  sexes 
  running 
  along 
  together 
  from 
  

   the 
  channel 
  towards 
  the 
  shore, 
  and 
  the 
  eggs 
  and 
  milt 
  being 
  ejected 
  

   simultaneous!}'. 
  On 
  quiet 
  evenings, 
  at 
  the 
  height 
  of 
  the 
  season, 
  

   spawning 
  shad 
  may 
  be 
  heard 
  surging 
  and 
  plunging 
  along 
  the 
  shores. 
  

   By 
  fishermen 
  this 
  is 
  termed 
  "washing." 
  

  

  Shad 
  are 
  very 
  prolific, 
  but 
  much 
  less 
  so 
  than 
  many 
  other 
  food-fishes. 
  

   The 
  quantities 
  of. 
  eggs 
  taken 
  by 
  spawn 
  -takers 
  do 
  not 
  represent 
  the 
  

   actual 
  fecundity, 
  for 
  many 
  are 
  cast 
  in 
  advance 
  of 
  stripping. 
  The 
  

   average 
  number 
  is 
  not 
  more 
  than 
  30,000. 
  Single 
  fish 
  have 
  been 
  known 
  

   to 
  yield 
  G0,000, 
  80,000, 
  100,000, 
  and 
  115,000 
  eggs; 
  and 
  on 
  the 
  Delaware 
  

   Eiver, 
  in 
  1885, 
  one 
  yielded 
  150,000. 
  Many 
  eggs 
  fail 
  to 
  be 
  fertilized, 
  

   and 
  but 
  a 
  comparatively 
  small 
  percentage 
  of 
  those 
  impregnated 
  are 
  

   hatched. 
  After 
  being 
  extruded, 
  the 
  eggs 
  sink 
  to 
  the 
  bottom, 
  wliere 
  

   they 
  remain 
  until 
  hatched, 
  subject 
  to 
  the 
  attacks 
  of 
  fish 
  and 
  other 
  

   water 
  animals. 
  Eels 
  are 
  very 
  destructive 
  to 
  shad 
  spawn 
  and 
  often 
  

   attack 
  shad 
  caught 
  in 
  gill 
  nets, 
  devouring 
  the 
  undeposited 
  eggs 
  and 
  

   sometimes 
  mutilating 
  half 
  the 
  catch 
  of 
  a 
  gill 
  net 
  fisherman. 
  

  

  The 
  development 
  of 
  fungus 
  is 
  one 
  of 
  the 
  greatest 
  dangers 
  to 
  shad 
  

   eggs 
  in 
  a 
  natural 
  state, 
  and 
  another 
  potent 
  agency 
  for 
  their 
  destruction 
  

   is 
  the 
  mud 
  brought 
  down 
  by 
  heavy 
  rains, 
  burying 
  and 
  suflbcating 
  

   the 
  eggs. 
  

  

  After 
  spawning, 
  sliad 
  are 
  denominated 
  "down-runners," 
  "racers,'' 
  

   and 
  "spent 
  fish." 
  They 
  are 
  then 
  very 
  lean 
  and 
  hardly 
  fit 
  for 
  food, 
  but 
  

   they 
  begin 
  to 
  feed 
  and 
  have 
  become 
  fatter 
  by 
  the 
  time 
  they 
  reach 
  salt 
  

   water 
  in 
  the 
  summer 
  or 
  fall. 
  

  

  