﻿MANUAL 
  OF 
  FISH-CULTURE. 
  

  

  183 
  

  

  The 
  fish 
  is 
  so 
  abundant, 
  however, 
  and 
  the 
  supply 
  so 
  well 
  maintained 
  

   that 
  fish-cultural 
  work 
  in 
  its 
  behalf 
  is 
  not 
  now 
  generally 
  required. 
  

  

  This 
  fish 
  spawns 
  in 
  late 
  winter 
  and 
  early 
  spring 
  in 
  the 
  fresh 
  waters 
  

   of 
  the 
  coast 
  rivers 
  and 
  in 
  the 
  Great 
  Lakes. 
  In 
  the 
  Potomac 
  River 
  

   spawning 
  takes 
  place 
  in 
  February, 
  March, 
  and 
  April. 
  The 
  water 
  tem- 
  

   perature 
  at 
  which 
  spawning 
  begins 
  is 
  about 
  44° 
  F., 
  while 
  49° 
  seems 
  to 
  

   mark 
  the 
  maximum 
  limit. 
  This 
  narrow 
  range 
  of 
  temperature 
  which 
  

   bounds 
  the 
  spawning 
  act 
  is 
  somewhat 
  noteworthy. 
  

  

  

  Ovary 
  of 
  a 
  yellow 
  perch 
  with 
  nearly-ripe 
  egi;s, 
  the 
  forked 
  

   extremity 
  beiug 
  the 
  auterior 
  part 
  of 
  the 
  roe. 
  

  

  The 
  eggs 
  of 
  the 
  yellow 
  perch 
  are 
  among 
  the 
  most 
  remarkable 
  that 
  have 
  

   been 
  artificially 
  hatched. 
  The 
  spawn 
  is 
  in 
  one 
  piece, 
  a 
  much 
  elongated 
  

   ribbon-like 
  structure, 
  of 
  a 
  semitransparent 
  light-grayish 
  color. 
  One 
  

   end 
  of 
  the 
  large 
  egg 
  mass, 
  corresponding 
  to 
  the 
  anterior 
  part 
  of 
  the 
  roe, 
  

   is 
  larger 
  than 
  the 
  other, 
  and 
  is 
  bluntly 
  forked. 
  The 
  string 
  is 
  very 
  long, 
  

  

  Part 
  of 
  a 
  receutly-laid 
  mass 
  of 
  yellow-perch 
  eggs. 
  

  

  but 
  may 
  be 
  much 
  compressed 
  lengthwise 
  by 
  virtue 
  of 
  its 
  arrangement 
  

   in 
  regular 
  transverse 
  folds 
  like 
  the 
  sides 
  of 
  a 
  bellows 
  or 
  accordeon. 
  

   When 
  deposited 
  the 
  eggs 
  are 
  in 
  a 
  loose 
  globular 
  form, 
  and 
  after 
  being 
  

   fertilized 
  and 
  becoming 
  "water-hard" 
  their 
  mass 
  rapidly 
  becomes 
  many 
  

   times 
  larger 
  than 
  the 
  fish 
  which 
  laid 
  them. 
  The 
  length 
  of 
  the 
  strings 
  

   is 
  from 
  12 
  to 
  more 
  than 
  7 
  feet, 
  depending 
  on 
  the 
  size 
  of 
  the 
  fish. 
  One 
  

  

  