﻿116 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  1 
  foot 
  2 
  inches 
  wide. 
  At 
  intervals 
  of 
  18 
  inches, 
  cleats 
  If 
  inches 
  high 
  

   are 
  mortised 
  across 
  the 
  bottom, 
  and 
  in 
  the 
  sides 
  of 
  the 
  trough, 
  at 
  

   the 
  ends 
  of 
  the 
  cleats, 
  grooves 
  are 
  made 
  to 
  admit 
  the 
  placing 
  of 
  a 
  flne- 
  

   meshed 
  vertical 
  screen, 
  which 
  can 
  fit 
  tightly 
  to 
  the 
  partition 
  at 
  the 
  

   bottom. 
  Everything 
  is 
  coated 
  Avith 
  asphaltum 
  paint. 
  The 
  trough 
  has 
  a 
  

   fall 
  of 
  (me-fifth 
  of 
  an 
  inch 
  to 
  the 
  foot, 
  the 
  overflow 
  being 
  at 
  tbe 
  end 
  

   through 
  a 
  tin 
  s])out. 
  Another 
  trough 
  may 
  be 
  set 
  at 
  the 
  lower 
  end 
  of 
  

   the 
  first, 
  provided, 
  as 
  with 
  hatching-troughs, 
  a 
  sulhcient 
  fall 
  is 
  given 
  for 
  

   aeration. 
  

  

  A 
  week 
  or 
  ten 
  days 
  before 
  the 
  disappearance 
  of 
  the 
  yolk-sac, 
  which 
  

   will 
  be 
  absorbed 
  in 
  five 
  or 
  six 
  weeks, 
  with 
  water 
  at 
  a 
  temperature 
  of 
  40° 
  

   to 
  45°, 
  the 
  fry 
  intended 
  for 
  rearing 
  should 
  be 
  transferred 
  to 
  the 
  troughs. 
  

   In 
  a 
  single 
  trough 
  of 
  the 
  size 
  described, 
  15 
  gallons 
  of 
  spring 
  water 
  per 
  

   minute, 
  with 
  a 
  temperature 
  ranging 
  from 
  45° 
  to 
  50° 
  F., 
  will 
  support 
  

   8,000 
  fry 
  during 
  the 
  first 
  few 
  weeks 
  they 
  are 
  held. 
  Uj) 
  to 
  this 
  time 
  it 
  is 
  

   not 
  necessary 
  to 
  insert 
  the 
  vertical 
  screens 
  except 
  at 
  the 
  head 
  and 
  out- 
  

   let, 
  but 
  as 
  the 
  fry 
  increase 
  in 
  size 
  they 
  become 
  restless, 
  snapping 
  at 
  each 
  

   other 
  and 
  crowding 
  together 
  in 
  a 
  mass 
  at 
  the 
  head 
  of 
  the 
  trough, 
  and 
  

   then 
  it 
  is 
  necessary 
  to 
  thin 
  them 
  out 
  and 
  separate 
  them 
  by 
  subdividing 
  

   the 
  troughs, 
  holding 
  an 
  equal 
  number 
  of 
  tbe 
  fry 
  in 
  each 
  of 
  the 
  compart- 
  

   ments. 
  The 
  action 
  of 
  the 
  fish 
  determines 
  when 
  this 
  should 
  be 
  done. 
  

   The 
  use 
  of 
  warm 
  water 
  hastens 
  the 
  development 
  of 
  the 
  fry, 
  the 
  same 
  as 
  

   it 
  does 
  with 
  the 
  eggs. 
  

  

  For 
  the 
  first 
  four 
  weeks 
  the 
  fry 
  are 
  fed 
  four 
  times 
  per 
  day 
  on 
  finely 
  

   choi)ped 
  beef 
  liver, 
  ladled 
  through 
  a 
  close 
  screen 
  to 
  remove 
  all 
  lumj)S. 
  

   The 
  liver 
  is 
  diluted 
  with 
  water 
  and 
  the 
  mixture 
  fed 
  to 
  the 
  fry 
  with 
  a 
  

   feather. 
  For 
  some 
  days 
  they 
  do 
  not 
  appear 
  to 
  take 
  their 
  food, 
  but 
  the 
  

   routine 
  is 
  continued, 
  and 
  as 
  soon 
  as 
  the 
  sac 
  is 
  entirely 
  consumed 
  they 
  

   commence 
  feeding. 
  No 
  rule 
  can 
  be 
  laid 
  down 
  prescribing 
  a 
  definite 
  

   amount 
  of 
  food, 
  but 
  the 
  fry 
  are 
  fed 
  till 
  their 
  appetites 
  are 
  appeased 
  and 
  

   every 
  fish 
  has 
  obtained 
  a 
  morsel. 
  Soine 
  days 
  they 
  display 
  more 
  hunger 
  

   than 
  usual, 
  a 
  warm 
  day 
  especially 
  increasing 
  their 
  appetites. 
  After 
  

   they 
  begin 
  to 
  feed 
  well 
  the 
  liver 
  may 
  be 
  given 
  to 
  them 
  but 
  three 
  times 
  a 
  

   day, 
  more 
  being 
  thrown 
  in 
  at 
  a 
  time. 
  

  

  The 
  troughs 
  must 
  be 
  cleaned 
  out 
  daily 
  by 
  turning 
  on 
  an 
  additional 
  

   supply 
  of 
  water 
  — 
  not 
  so 
  much 
  that 
  the 
  fish 
  will 
  be 
  carried 
  against 
  the 
  

   screen 
  — 
  and 
  the 
  foul 
  matter 
  stirred 
  up 
  from 
  the 
  bottom 
  with 
  a 
  feather 
  

   and 
  worked 
  through 
  the 
  wires 
  with 
  a 
  small 
  sponge. 
  Twice 
  a 
  week 
  the 
  

   sides 
  and 
  bottom 
  are 
  sponged 
  ott'. 
  

  

  Three 
  months 
  after 
  being 
  transferred 
  to 
  the 
  feeding-troughs, 
  trout 
  

   will 
  take 
  food 
  well 
  and 
  be 
  from 
  1 
  to 
  2 
  inches 
  long. 
  They 
  are 
  then 
  ready 
  

   to 
  go 
  outside 
  to 
  the 
  rearing-pouds. 
  These 
  ponds 
  are 
  about 
  32 
  feet 
  long- 
  

   by 
  5 
  feet 
  wide, 
  with 
  from 
  10 
  to 
  20 
  inches 
  of 
  water, 
  and 
  have 
  a 
  minimum 
  

   water 
  supply 
  of 
  20 
  gallons 
  per 
  minute. 
  The 
  bottom 
  is 
  graveled 
  and 
  

   the 
  sides 
  constructed 
  of 
  planks 
  or 
  cobblestones, 
  and 
  on 
  the 
  sides 
  where 
  

   the 
  sun 
  strikes 
  the 
  warmest 
  during 
  the 
  day 
  a 
  board 
  shades 
  the 
  trout 
  

  

  