﻿58 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  seasons. 
  Fish 
  may 
  also 
  be 
  kept 
  all 
  winter 
  in 
  troughs 
  in 
  the 
  open 
  air 
  

   by 
  occasionally 
  spreading 
  blankets 
  over 
  them 
  in 
  exceptionally 
  cold 
  

   weather, 
  and 
  keeping 
  the 
  conduits 
  carefully 
  covered. 
  

  

  The 
  fish 
  surviving 
  the 
  summer 
  season 
  are 
  generally 
  counted 
  and 
  

   weighed 
  in 
  October, 
  in 
  the 
  following 
  manner 
  : 
  A 
  large 
  number 
  of 
  them 
  

   are 
  dipi^ed 
  up 
  from 
  a 
  trough 
  in 
  a 
  small 
  dip 
  net 
  made 
  of 
  cheese-cloth, 
  

   and 
  from 
  this, 
  while 
  it 
  is 
  hanging 
  in 
  the 
  water 
  in 
  such 
  a 
  manner 
  that 
  

   the 
  fish 
  can 
  not 
  escape, 
  they 
  are 
  dipped 
  out 
  a 
  few 
  at 
  a 
  time, 
  in 
  a 
  small 
  

   dipper 
  or 
  cup, 
  counted, 
  and 
  placed 
  in 
  another 
  bag 
  net 
  until 
  a 
  sufficient 
  

   number 
  (generally 
  200) 
  are 
  counted, 
  when 
  they 
  are 
  lifted 
  out 
  of 
  the 
  

   water, 
  held 
  a 
  moment 
  in 
  the 
  air 
  to 
  drain, 
  and 
  all 
  turned 
  quickly 
  into 
  

   a 
  pail 
  of 
  water 
  which 
  has 
  previously 
  been 
  weighed. 
  With 
  care 
  no 
  

   appreciable 
  amount 
  of 
  water 
  goes 
  with 
  the 
  fish, 
  and 
  the 
  increase 
  in 
  the 
  

   reading 
  indicates 
  their 
  weight 
  with 
  a 
  fair 
  approach 
  to 
  accuracy, 
  and 
  

   with 
  care 
  and 
  celerity 
  of 
  action 
  it 
  is 
  quite 
  safe 
  for 
  the 
  fish. 
  

  

  The 
  size 
  attained 
  by 
  tlie 
  fish 
  varies 
  greatly, 
  being 
  affected 
  by 
  the 
  

   water, 
  the 
  space 
  allowed, 
  the 
  feed, 
  and 
  perhaps 
  by 
  hereditary 
  influences; 
  

   but 
  when 
  seven 
  months 
  old 
  a 
  trough-reared 
  salmon 
  is 
  generally 
  from 
  

   2i 
  to 
  3 
  inches 
  long 
  and 
  weighs 
  from 
  35 
  to 
  100 
  grains, 
  the 
  maximum 
  being 
  

   about 
  130 
  grains 
  and 
  the 
  minimum 
  as 
  low 
  as 
  7 
  grains, 
  the 
  general 
  

   mean 
  for 
  189G 
  being 
  45.8 
  grains. 
  Salmon 
  reared 
  in 
  ponds 
  have 
  been 
  far 
  

   more 
  thrifty, 
  their 
  general 
  average 
  in 
  1896 
  being 
  101 
  grains.* 
  The 
  

   losses 
  in 
  ponds 
  from 
  July 
  to 
  October 
  were 
  rather 
  heavy, 
  being 
  11.7 
  i)er 
  

   cent, 
  owing 
  to 
  depredations 
  of 
  frogs, 
  birds, 
  and 
  cannibal 
  fish. 
  The 
  

   losses 
  in 
  the 
  troughs 
  during 
  the 
  entire 
  season 
  were 
  9.1 
  per 
  cent, 
  but 
  

   most 
  of 
  these 
  were 
  in 
  the 
  early 
  stages 
  of 
  fryhood. 
  After 
  July 
  losses 
  in 
  

   troughs 
  are 
  always 
  very 
  light. 
  

  

  MATERIALS 
  FOR 
  FISH 
  FOOD. 
  

  

  At 
  Craig 
  Brook 
  station 
  there 
  have 
  been 
  used 
  butchers' 
  offal, 
  flesh 
  of 
  

   horses 
  and 
  other 
  domestic 
  animals, 
  fresh 
  fish, 
  and 
  maggots. 
  Experi- 
  

   ments 
  have 
  also 
  been 
  made 
  with 
  pickled 
  fish, 
  blood, 
  fresh-water 
  

   mussels, 
  mosquito 
  larvje, 
  miscellaneous 
  aquatic 
  animals 
  of 
  minute 
  size, 
  

  

  '^A 
  very 
  interesting 
  comparison 
  between 
  the 
  results 
  of 
  rearing 
  in 
  troughs 
  and 
  

   ponds 
  is 
  afforded 
  by 
  the 
  record 
  of 
  two 
  lots 
  of 
  steelhead 
  trout 
  during 
  the 
  season 
  of 
  

   1896. 
  All 
  the 
  fry 
  of 
  this 
  species 
  that 
  were 
  devoted 
  to 
  rearing 
  were 
  fed 
  in 
  troughs 
  

   until 
  July 
  22, 
  when 
  some 
  of 
  them 
  were 
  transferred 
  to 
  a 
  pond 
  which 
  has 
  ^n 
  area 
  of 
  

   about 
  1,100 
  square 
  feet 
  and 
  another 
  lot 
  was 
  kept 
  in 
  a 
  trough. 
  The 
  two 
  lots 
  were 
  fed 
  

   exactly 
  alike, 
  about 
  one-sixth 
  of 
  their 
  nutriment 
  being 
  liv 
  maggots, 
  and 
  tive-sixths 
  

   chopped 
  meat, 
  liver, 
  and 
  other 
  butchers' 
  offal. 
  November 
  7, 
  the 
  lot 
  in 
  the 
  trough 
  

   was 
  overhauled, 
  and 
  the 
  762 
  survivors 
  found 
  to 
  weigh 
  10 
  pounds 
  4 
  ounces, 
  or 
  an 
  

   average 
  of 
  94 
  grains. 
  Three 
  days 
  later 
  the 
  pond 
  fish 
  were 
  seined 
  out 
  and 
  the 
  7,398 
  

   survivors 
  found 
  to 
  weigh 
  235 
  pounds 
  10 
  ounces, 
  an 
  average 
  of 
  223 
  grains. 
  It 
  is 
  not 
  

   believed 
  that 
  natural 
  food 
  occurring 
  in 
  the 
  pond 
  contributed 
  much 
  to 
  this 
  result, 
  and 
  

   it 
  would 
  appear 
  that 
  the 
  controlling 
  factor 
  in 
  the 
  case 
  was 
  the 
  space 
  afforded 
  the 
  

   fish. 
  Leaving 
  out 
  of 
  the 
  account 
  the 
  difference 
  in 
  depth, 
  in 
  the 
  pond 
  there 
  were 
  less 
  

   than 
  7 
  fish 
  to 
  each 
  square 
  foot 
  of 
  area, 
  while 
  in 
  the 
  trough, 
  which 
  had 
  an 
  area 
  of 
  

   about 
  11 
  square 
  feet, 
  there 
  were 
  to 
  each 
  square 
  foot 
  69 
  fish. 
  A 
  similar 
  illustration 
  

   was 
  furnished 
  by 
  41 
  rainbow 
  trout 
  of 
  the 
  hatching 
  of 
  1896 
  that 
  got 
  astray 
  in 
  one 
  of 
  

   the 
  ponds 
  and 
  were 
  taken 
  out 
  November 
  11, 
  weighing 
  480 
  grains 
  each. 
  Those 
  

   of 
  the 
  same 
  age, 
  reared 
  in 
  troughs, 
  attained 
  during 
  the 
  season 
  only 
  a 
  weight 
  of 
  136i^ 
  

   grains 
  each. 
  

  

  