﻿MANUAL 
  OF 
  FISH-CULTURE. 
  25 
  

  

  iron 
  wire, 
  with 
  meshes 
  | 
  by 
  ^ 
  of 
  an 
  inch, 
  fastened 
  at 
  the 
  top 
  to 
  a 
  wooden 
  

   frame 
  ^ 
  inch 
  thick. 
  They 
  are 
  23 
  inches 
  Jong, 
  15i 
  inches 
  wide 
  at 
  toj), 
  

   15 
  inches 
  at 
  bottom, 
  and 
  6 
  inches 
  deep. 
  When 
  placed 
  in 
  the 
  hatching- 
  

   trough 
  the 
  wooden 
  frame 
  of 
  the 
  basket 
  rests 
  on 
  the 
  edge 
  of 
  the 
  trough. 
  

  

  Two 
  division 
  plates 
  of 
  galvanized 
  iron 
  are 
  placed 
  in 
  the 
  hatching- 
  

   trough 
  just 
  above 
  each 
  basket. 
  The 
  first 
  one 
  rests 
  on 
  the 
  bottom 
  

   and 
  extends 
  to 
  within 
  an 
  inch 
  of 
  the 
  surface 
  of 
  the 
  water; 
  the 
  second 
  is 
  

   placed 
  half 
  an 
  inch 
  below 
  the 
  first 
  one, 
  and 
  extends 
  from 
  the 
  top 
  of 
  the 
  

   box 
  to 
  within 
  an 
  inch 
  of 
  the 
  bottom. 
  This 
  causes 
  an 
  upward 
  current 
  of 
  

   water 
  to 
  pass 
  through 
  the 
  eggs, 
  which, 
  however, 
  is 
  not 
  strong 
  enough 
  

   to 
  move 
  them. 
  

  

  From 
  the 
  second 
  to 
  the 
  tenth 
  day 
  the 
  eggs 
  are 
  washed 
  and 
  the 
  dead 
  

   eggs 
  are 
  picked 
  out, 
  but 
  from 
  the 
  tenth 
  to 
  the 
  fifteenth 
  day 
  they 
  are 
  

   not 
  handled 
  in 
  any 
  manner, 
  no 
  matter 
  how 
  nuich 
  sediment 
  may 
  cover 
  

   them. 
  After 
  the 
  fifteenth 
  day, 
  or 
  when 
  the 
  young 
  fish 
  is 
  well 
  defined 
  

   in 
  the 
  egg, 
  washing 
  and 
  picking 
  is 
  renewed 
  and 
  continued 
  daily 
  until 
  

   the 
  eggs 
  are 
  packed 
  for 
  shipment. 
  

  

  Tbe 
  method 
  of 
  handling 
  is 
  determined 
  by 
  the 
  conditions, 
  a 
  lower 
  

   temperature 
  allowing 
  them 
  to 
  be 
  washed 
  beyond 
  the 
  tenth 
  day, 
  but 
  

   the 
  above 
  noted 
  is 
  the 
  average 
  for 
  the 
  season 
  of 
  1896. 
  The 
  total 
  loss 
  

   in 
  eyeing 
  (that 
  is, 
  carrying 
  eggs 
  from 
  time 
  of 
  taking 
  until 
  the 
  eye- 
  

   spots 
  appear) 
  during 
  the 
  season 
  was 
  1,308,290, 
  or 
  5.0G 
  per 
  cent. 
  No 
  

   eggs 
  were 
  hatched 
  at 
  Battle 
  Creek 
  station, 
  as 
  the 
  water 
  supply 
  was 
  

   considered 
  unsafe. 
  

  

  In 
  packing 
  eggs 
  for 
  shipment 
  no 
  ice 
  is 
  used 
  except 
  for 
  long 
  distances. 
  

  

  The 
  eggs 
  received 
  at 
  the 
  Sisson 
  station 
  of 
  the 
  California 
  Fish 
  Com- 
  

   mission, 
  located 
  at 
  the 
  headwaters 
  of 
  the 
  Sacramento 
  River, 
  are 
  treated 
  

   by 
  methods 
  similar 
  to 
  those 
  already 
  described 
  as 
  being 
  used 
  at 
  Battle 
  

   Creek. 
  The 
  average 
  number 
  of 
  days 
  taken 
  to 
  hatch 
  the 
  eggs 
  is 
  42, 
  

   and 
  the 
  alevius 
  absorb 
  the 
  sac 
  in 
  from 
  30 
  to 
  40 
  days 
  at 
  an 
  average 
  

   temperature 
  of 
  44°. 
  After 
  the 
  eggs 
  are 
  hatched, 
  the 
  division 
  plates 
  

   resting 
  upon 
  the 
  bottom 
  of 
  each 
  trough 
  are 
  removed 
  and 
  the 
  remaining 
  

   plates 
  lowered 
  to 
  within 
  half 
  an 
  inch 
  of 
  the 
  bottom 
  of 
  the 
  hatching- 
  

   trough. 
  This 
  divides 
  the 
  trough 
  into 
  sections 
  and 
  results 
  in 
  a 
  stift" 
  

   current 
  running 
  under 
  each 
  plate, 
  which 
  prevents 
  the 
  massing 
  of 
  the 
  

   alevins 
  at 
  the 
  head 
  of 
  the 
  trough. 
  At 
  this 
  time, 
  a 
  A-shaped 
  piece 
  of 
  

   galvanized 
  iron, 
  termed 
  a 
  harbor 
  plate, 
  is 
  placed 
  in 
  each 
  trough 
  4 
  inches 
  

   above 
  the 
  retaining- 
  screen, 
  with 
  its 
  apex 
  against 
  the 
  current; 
  it 
  extends 
  

   to 
  within 
  an 
  inch 
  of 
  each 
  side 
  of 
  the 
  trough 
  and 
  rises 
  to 
  the 
  surface 
  of 
  

   the 
  water. 
  The 
  water 
  in 
  passing 
  around 
  each 
  end 
  of 
  the 
  plate 
  causes 
  

   an 
  eddy 
  that 
  carries 
  the 
  weak 
  alevins 
  away 
  from 
  the 
  screen 
  into 
  the 
  

   angle 
  of 
  the 
  plate, 
  aftbrding 
  them 
  a 
  harbor 
  of 
  rest 
  and 
  preventing 
  their 
  

   being 
  held 
  against 
  the 
  screen. 
  

  

  The 
  loss 
  of 
  alevins 
  while 
  absorbing 
  the 
  sac 
  is 
  slight. 
  The 
  space 
  for 
  

   hatching- 
  troughs 
  at 
  Sisson 
  is 
  limited; 
  and 
  to 
  relieve 
  the 
  troughs 
  the 
  

   planting 
  of 
  alevins 
  begins 
  a 
  few 
  days 
  after 
  they 
  hatch 
  j 
  hence 
  the 
  exact 
  

  

  