﻿94 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  the 
  deep 
  pools 
  and 
  eddies 
  where 
  it 
  can 
  lie 
  concealed 
  beneath 
  the 
  shelter 
  

   of 
  grassy 
  banks 
  or 
  logs, 
  and 
  see 
  without 
  being 
  seen. 
  Under 
  artificial 
  

   conditions 
  it 
  endures 
  higher 
  temperature 
  than 
  in 
  its 
  native 
  waters, 
  

   where 
  it 
  is 
  seldom 
  found 
  in 
  water 
  warmer 
  than 
  60° 
  to 
  65°. 
  It 
  thrives 
  

   at 
  much 
  higher 
  temperature 
  in 
  swift, 
  well-aerated 
  streams 
  than 
  in 
  

   sluggish 
  waters. 
  

  

  The 
  brook 
  trout 
  si^awns 
  in 
  autumn 
  during 
  the 
  falling 
  of 
  the 
  water 
  

   temperature. 
  The 
  season, 
  which 
  usually 
  lasts 
  about 
  two 
  months, 
  begins 
  

   earlier 
  in 
  northern 
  latitudes, 
  in 
  the 
  Lake 
  Superior 
  region 
  in 
  September 
  

   or 
  even 
  August, 
  while 
  in 
  New 
  York, 
  New 
  England, 
  and 
  lower 
  Michigan 
  

   it 
  commences 
  about 
  the 
  middle 
  of 
  October. 
  

  

  As 
  the 
  spawning 
  time 
  ax)proaches 
  the 
  fish 
  push 
  up 
  toward 
  the 
  

   shallower 
  waters 
  where 
  the 
  female 
  selects 
  a 
  spot 
  near 
  the 
  bank 
  of 
  the 
  

   stream 
  and 
  prepares 
  her 
  nest 
  by 
  washing 
  out 
  the 
  sand 
  with 
  her 
  tail 
  

   and 
  pushing 
  aside 
  the 
  gravel 
  with 
  her 
  nose. 
  After 
  forming 
  a 
  slightly 
  

   concave 
  depression 
  she 
  deposits 
  a 
  part 
  of 
  her 
  eggs 
  on 
  the 
  newly 
  cleansed 
  

   gravel, 
  and 
  the 
  male 
  — 
  which 
  up 
  to 
  this 
  time 
  has 
  been 
  playfully 
  swim- 
  

   ming 
  around 
  the 
  nest 
  — 
  emits 
  milt 
  upon 
  them 
  almost 
  simultaneously. 
  

   The 
  female 
  then 
  covers 
  the 
  eggs 
  with 
  the 
  loose 
  gravel. 
  The 
  spawning, 
  

   impregnating, 
  and 
  covering 
  are 
  repeated 
  continuously 
  until 
  the 
  eggs 
  

   are 
  all 
  laid. 
  After 
  the 
  spawning-ground 
  is 
  once 
  selected 
  it 
  is 
  hard 
  to 
  

   drive 
  the 
  fish 
  away, 
  the 
  female 
  especially 
  returning 
  to 
  the 
  same 
  spot 
  at 
  

   the 
  earliest 
  opportunity. 
  A 
  female 
  has 
  been 
  taken 
  from 
  her 
  nest 
  and 
  

   marked 
  and 
  then 
  returned 
  to 
  the 
  water 
  a 
  mile 
  down 
  the 
  stream, 
  and 
  

   the 
  next 
  morning 
  was 
  found 
  on 
  the 
  same 
  bed 
  as 
  though 
  nothing 
  had 
  

   happened. 
  

  

  The 
  eggs 
  vary 
  in 
  size, 
  but 
  are 
  usually 
  one-sixth 
  of 
  an 
  inch 
  in 
  

   diameter. 
  The 
  number 
  yielded 
  by 
  one 
  fish 
  depends 
  on 
  its 
  size 
  and 
  age, 
  

   yearlings 
  usually 
  producing 
  from 
  150 
  to 
  250, 
  two-year-olds 
  350 
  to 
  500, 
  

   and 
  older 
  fish 
  500 
  to 
  1,500. 
  The 
  time 
  necessary 
  for 
  developing 
  the 
  eggs 
  

   is 
  dependent 
  on 
  the 
  temperature 
  of 
  the 
  water, 
  varying 
  from 
  about 
  125 
  

   days 
  in 
  water 
  at 
  37° 
  F. 
  to 
  about 
  50 
  days 
  in 
  water 
  at 
  50° 
  F. 
  

  

  TROUT-CULTURE 
  IN 
  AMERICA. 
  

  

  The 
  first 
  attempt 
  at 
  artificial 
  trout-culture 
  in 
  America 
  was 
  made 
  in 
  

   Ohio 
  in 
  1853 
  and 
  marked 
  success 
  attended 
  the 
  efforts. 
  Further 
  satis- 
  

   factory 
  trials 
  were 
  made 
  in 
  1855 
  and 
  1859 
  in 
  Connecticut 
  and 
  New 
  York, 
  

   and 
  in 
  1804 
  a 
  hatchery 
  was 
  established 
  in 
  New 
  York 
  which 
  became 
  a 
  

   practical 
  success 
  in 
  carrying 
  on 
  the 
  work 
  on 
  a 
  large 
  scale. 
  Somewhat 
  

   later 
  the 
  work 
  was 
  taken 
  up 
  by 
  the 
  State 
  and 
  United 
  States 
  govern- 
  

   ments 
  and 
  is 
  now 
  very 
  extensively 
  carried 
  on 
  in 
  all 
  parts 
  of 
  the 
  United 
  

   States. 
  

  

  The 
  methods 
  described 
  in 
  the 
  following 
  pages 
  are 
  those 
  which 
  have 
  

   been 
  found 
  advantageous 
  at 
  the 
  Northville 
  station, 
  and 
  are 
  there 
  pur- 
  

   sued. 
  In 
  addition 
  to 
  the 
  eggs 
  obtained 
  from 
  brood 
  fish 
  held 
  in 
  ponds 
  

   at 
  the 
  hatchery 
  a 
  field 
  station 
  for 
  collecting 
  eggs 
  from 
  wild 
  trout 
  is 
  

   operated 
  on 
  the 
  An 
  Sable 
  Eiver. 
  

  

  