﻿MANUAL 
  OF 
  FISH-CULTURE. 
  Ill 
  

  

  or 
  if 
  it 
  abounds 
  with 
  aquatic 
  insects, 
  it 
  is 
  quite 
  essential 
  to 
  have 
  some 
  

   kind 
  of 
  filtration, 
  otherwise 
  the 
  eggs 
  may 
  be 
  injured 
  by 
  animalculae 
  

   or 
  coated 
  with 
  sediment, 
  the 
  trays 
  clogged 
  with 
  refuse, 
  the 
  circulation 
  

   stopped, 
  and 
  in 
  the 
  end 
  a 
  majority 
  of 
  the 
  eggs 
  lost. 
  Many 
  filters 
  

   have 
  been 
  devised, 
  all 
  of 
  which 
  are 
  good, 
  but 
  a 
  simple 
  and 
  effective 
  

   contrivance 
  is 
  made 
  by 
  tacking 
  medium- 
  weight 
  flannel 
  to 
  wooden 
  tray 
  

   frames 
  and 
  placing 
  them 
  at 
  the 
  head 
  of 
  the 
  tank 
  directly 
  beneath 
  the 
  

   head 
  of 
  water, 
  the 
  number 
  used 
  at 
  one 
  point 
  being 
  governed 
  by 
  the 
  

   amount 
  of 
  sediment 
  or 
  other 
  foreign 
  matter 
  present. 
  

  

  At 
  North 
  ville, 
  as 
  a 
  convenience 
  in 
  caring 
  for 
  eggs, 
  a 
  shallow 
  "picking- 
  

   trough" 
  is 
  used, 
  40 
  feet 
  long, 
  10 
  inches 
  wide, 
  and 
  2i 
  inches 
  deep, 
  with 
  

   a 
  i-iuch 
  strip, 
  ^ 
  of 
  an 
  inch 
  wide, 
  nailed 
  along 
  eacli 
  side 
  of 
  the 
  bottom, 
  

   upon 
  which 
  the 
  trays 
  rest, 
  to 
  give 
  a 
  good 
  circulation 
  while 
  the 
  eggs 
  are 
  

   sorted 
  over. 
  The 
  trough 
  has 
  a 
  fall 
  of 
  not 
  more 
  than 
  J 
  inch 
  throughout 
  

   its 
  entire 
  length, 
  and 
  it 
  is 
  fed 
  by 
  a 
  flow 
  of 
  about 
  2 
  gallons 
  of 
  water 
  

   l)er 
  minute. 
  A 
  dam 
  at 
  its 
  lower 
  end 
  raises 
  the 
  water 
  1^ 
  inches, 
  not 
  

   entirely 
  covering 
  the 
  trays. 
  This 
  is 
  a 
  point 
  that 
  must 
  not 
  be 
  over- 
  

   looked, 
  for 
  if 
  the 
  water 
  flows 
  over 
  the 
  tops 
  of 
  the 
  trays 
  many 
  of 
  the 
  

   eggs 
  and 
  fry 
  will 
  be 
  apt 
  to 
  escape 
  through 
  the 
  waste-pipe. 
  

  

  CARE 
  OF 
  THE 
  EGGS 
  AND 
  FRY. 
  

  

  Upon 
  their 
  arrival 
  at 
  the 
  hatchery 
  the 
  eggs 
  are 
  taken 
  from 
  the 
  

   shipping-cases 
  and 
  turned 
  into 
  tubs, 
  whence 
  they 
  are 
  removed 
  to 
  the 
  

   hatching-troughs. 
  In 
  removing 
  eggs 
  from 
  the 
  flannel 
  shipping 
  trays 
  

   to 
  the 
  tub 
  the 
  same 
  method 
  is 
  followed 
  as 
  in 
  washing 
  eggs 
  that 
  have 
  

   been 
  held 
  in 
  cases 
  for 
  several 
  days. 
  The 
  transfer 
  should 
  take 
  place 
  in 
  

   a 
  temperature 
  not 
  higher 
  than 
  45° 
  or 
  50° 
  F., 
  and 
  if 
  the 
  eggs 
  are 
  held 
  

   in 
  the 
  tubs 
  for 
  any 
  length 
  of 
  time 
  they 
  are 
  given 
  a 
  change 
  of 
  water 
  

   every 
  30 
  minutes. 
  

  

  Great 
  care 
  is 
  necessary 
  in 
  transferring 
  eggs 
  to 
  the 
  hatching-trough 
  

   in 
  pails. 
  To 
  guard 
  against 
  any 
  shock, 
  the 
  pail 
  is 
  partially 
  filled 
  with 
  

   water, 
  and 
  the 
  eggs 
  are 
  carefully 
  taken 
  in 
  the 
  dipper, 
  which 
  is 
  lowered 
  

   into 
  the 
  ])ail 
  in 
  such 
  a 
  way 
  that 
  the 
  eggs 
  will 
  glide 
  into 
  the 
  water 
  and 
  not 
  

   fall 
  upon 
  it. 
  The 
  pail 
  when 
  filled 
  is 
  placed 
  upon 
  the 
  trough 
  as 
  near 
  as 
  

   possible 
  to 
  the 
  box 
  for 
  which 
  the 
  eggs 
  are 
  intended, 
  and 
  by 
  means 
  of 
  a 
  

   perforated 
  dipper 
  with 
  a 
  capacity 
  of 
  20 
  ounces, 
  or 
  4,000 
  eggs, 
  they 
  are 
  

   transferred 
  to 
  the 
  hatching 
  boxes. 
  A 
  tray 
  is 
  placed 
  in 
  the 
  water 
  and 
  

   one 
  dipperful 
  poured 
  upon 
  it, 
  whereupon 
  a 
  second 
  tray, 
  placed 
  on 
  top 
  

   of 
  the 
  first, 
  is 
  served 
  in 
  like 
  manner, 
  and 
  this 
  is 
  rei^eated 
  until 
  ten 
  trays 
  

   are 
  filled. 
  The 
  eleventh, 
  or 
  cover 
  tray, 
  is 
  left 
  empty, 
  and 
  the 
  whole 
  

   apparatus 
  is 
  held 
  in 
  place 
  with 
  a 
  crossbar 
  or 
  binder. 
  In 
  two 
  double 
  

   troughs, 
  containing 
  G4 
  boxes 
  and 
  occupying 
  a 
  floor 
  space 
  of 
  100 
  square 
  

   feet, 
  2,560,000 
  eggs 
  may 
  be 
  safely 
  carried 
  with 
  22 
  gallons 
  per 
  minute 
  

   of 
  good 
  spring 
  or 
  lake 
  water, 
  well 
  aerated. 
  

  

  To 
  estimate 
  the 
  number 
  of 
  eggs 
  laid 
  down, 
  a 
  fractional 
  jiortion 
  of 
  a 
  

   quart 
  is 
  counted 
  several 
  times 
  until 
  a 
  satisfactory 
  average 
  i.^ 
  arrived 
  at; 
  

   this 
  has 
  given 
  200 
  to 
  the 
  linid 
  o'.ince, 
  or 
  0,400 
  to 
  the 
  quart. 
  

  

  