﻿MANUAL 
  OF 
  FISH-CULTURE. 
  ISO 
  

  

  water, 
  and 
  must 
  have 
  a 
  very 
  abundant 
  growth 
  of 
  myriophyllum 
  or 
  

   other 
  water 
  plants. 
  In 
  the 
  latitude 
  of 
  Washington, 
  D. 
  0., 
  spawning 
  

   takes 
  place 
  in 
  April. 
  The 
  fish 
  makes 
  no 
  nest, 
  but 
  deposits 
  its 
  eggs 
  on 
  

   water-plants, 
  gravel, 
  stones, 
  and 
  other 
  substances. 
  The 
  eggs 
  being 
  

   adhesive, 
  like 
  those 
  of 
  most 
  cyprinoid 
  fishes, 
  become 
  attached 
  as 
  soon 
  

   as 
  ejected, 
  and 
  so 
  remain 
  until 
  hatched. 
  The 
  eggs 
  are 
  about 
  iV 
  i^ch 
  in 
  

   diameter. 
  They 
  are 
  extremely 
  tender, 
  and 
  it 
  is 
  important 
  that 
  at 
  the 
  

   time 
  of 
  spawning 
  the 
  water 
  be 
  of 
  an 
  even 
  temperature. 
  

  

  Under 
  favorable 
  conditions 
  the 
  eggs 
  develop 
  rapidly, 
  and 
  at 
  a 
  mean 
  

   temperature 
  of 
  5Q^ 
  F. 
  hatch 
  in 
  5 
  or 
  6 
  days. 
  In 
  suitable 
  ponds, 
  with 
  

   plenty 
  of 
  shade 
  and 
  a 
  healthy 
  growth 
  of 
  plants, 
  the 
  natural 
  food 
  that 
  

   the 
  fry 
  will 
  secure 
  renders 
  artificial 
  feeding 
  unnecessary 
  for 
  a 
  month 
  or 
  

   more. 
  After 
  the 
  fifth 
  or 
  sixth 
  week 
  the 
  young 
  may 
  be 
  given 
  small 
  

   quantities 
  of 
  cooked 
  corn-meal 
  mixed 
  with 
  flour. 
  They 
  take 
  finely 
  

   divided 
  fish 
  flesh, 
  bivalves, 
  and 
  crayfish, 
  but 
  the 
  main 
  dependence 
  

   should 
  be 
  on 
  the 
  corn-meal 
  flour 
  mixture. 
  

  

  At 
  the 
  end 
  of 
  six 
  months 
  the 
  young 
  have 
  attained 
  a 
  length 
  of 
  3 
  inches, 
  

   and 
  in 
  a 
  year 
  are 
  6 
  inches 
  long. 
  Maturity 
  is 
  attained 
  at 
  an 
  age 
  of 
  3 
  

   years. 
  

  

  THE 
  STURGEONS. 
  

  

  There 
  are 
  six 
  species 
  of 
  sturgeon 
  in 
  the 
  waters 
  of 
  the 
  United 
  States. 
  

   The 
  common 
  and 
  the 
  short-nose 
  sturgeons 
  [Acipenser 
  sturio 
  and 
  A. 
  

   'brevirostris) 
  are 
  found 
  only 
  on 
  the 
  Atlantic 
  Coast, 
  ascending 
  rivers 
  to 
  

   spawn. 
  The 
  white 
  sturgeon 
  and 
  green 
  sturgeon 
  {A. 
  transmontanus 
  and 
  

   A. 
  medirostris) 
  inhabit 
  only 
  the 
  waters 
  of 
  the 
  Pacific 
  Coast. 
  The 
  lake 
  

   sturgeon 
  or 
  rock 
  sturgeon 
  {A.rubicundus) 
  exists 
  in 
  the 
  Great 
  Lakes, 
  the 
  

   Upper 
  Mississippi 
  Valley, 
  and 
  other 
  northern 
  interior 
  waters. 
  The 
  

   shovel-nose 
  sturgeon 
  or 
  white 
  sturgeon 
  {Scaphirhynchus 
  platyrhynchus) 
  

   is 
  found 
  in 
  the 
  Mississippi 
  and 
  other 
  streams 
  of 
  the 
  Southern 
  and 
  

   Western 
  States. 
  

  

  While 
  all 
  of 
  the 
  sturgeons 
  are 
  edible 
  and 
  caught 
  for 
  market, 
  the 
  

   most 
  valuable 
  species 
  are 
  the 
  common 
  sturgeon 
  and 
  the 
  lake 
  sturgeon, 
  

   which 
  alone 
  have 
  been 
  artificially 
  propagated. 
  

  

  The 
  catching 
  of 
  sturgeon 
  for 
  market 
  is 
  a 
  business 
  of 
  comparatively 
  

   recent 
  origin. 
  A 
  few 
  years 
  ago 
  enormous 
  numbers 
  were 
  annually 
  killed 
  

   and 
  thrown 
  away 
  by 
  salmon, 
  shad, 
  and 
  whitefish 
  fishermen, 
  to 
  whom 
  they 
  

   were 
  of 
  no 
  value. 
  The 
  special 
  apparatus 
  employed 
  in 
  taking 
  sturgeon 
  

   consists 
  of 
  gill 
  nets 
  and 
  set 
  lines, 
  but 
  many 
  are 
  caught 
  in 
  pound 
  nets, 
  

   seines, 
  etc., 
  set 
  primarily 
  for 
  other 
  fish. 
  The 
  principal 
  fisheries 
  are 
  in 
  

   the 
  Great 
  Lakes, 
  Delaware 
  River, 
  and 
  Sacramento 
  River. 
  The 
  present 
  

   yearly 
  value 
  of 
  the 
  yield 
  is 
  about 
  $300,000. 
  Very 
  important 
  secondary 
  

   products 
  are 
  derived 
  from 
  the 
  sturgeon, 
  namely, 
  caviar, 
  isinglass, 
  and 
  oil. 
  

  

  The 
  sturgeon 
  fishery 
  is 
  declining, 
  and 
  affords 
  a 
  remarkable 
  illustra- 
  

   tion 
  of 
  the 
  comparative 
  facility 
  with 
  which 
  the 
  supply 
  of 
  river 
  and 
  lake 
  

   fishes 
  may 
  be 
  exhausted 
  by 
  indiscriminate 
  fishing. 
  In 
  some 
  localities 
  

   the 
  change 
  in 
  the 
  sturgeon 
  fishery 
  within 
  a 
  single 
  decade 
  has 
  been 
  from 
  

   a 
  condition 
  of 
  great 
  abundance, 
  with 
  little 
  appreciation 
  of 
  the 
  value 
  of 
  

  

  