﻿WATER-POWER 
  DEVELOPMENT 
  IN 
  THE 
  MISSISSIPPI. 
  9 
  

  

  in 
  other 
  parts. 
  A 
  river-lake'^ 
  fauna 
  of 
  mussels 
  may 
  replace 
  a 
  strictly 
  

   river 
  fauna. 
  Should 
  Lake 
  Cooper 
  eventually 
  rival 
  Lake 
  Pepin 
  — 
  ^a 
  

   condition 
  scarcely 
  to 
  be 
  hoped 
  for- 
  — 
  it 
  will 
  be 
  one 
  of 
  the 
  most 
  impor- 
  

   tant 
  mussel 
  regions 
  of 
  the 
  country, 
  supporting 
  a 
  mussel 
  fishery 
  

   exceeding 
  anything 
  known 
  in 
  this 
  territory 
  before. 
  

  

  In 
  concluding 
  this 
  introduction, 
  certain 
  saUent 
  points 
  wliich 
  have 
  

   been 
  brought 
  out 
  or 
  implied 
  merit 
  a 
  particular 
  emphasis. 
  

  

  (1) 
  While 
  the 
  value 
  of 
  the 
  dam 
  will 
  never 
  be 
  measured 
  by 
  its 
  

   relation 
  to 
  the 
  fishery, 
  the 
  effects, 
  both 
  direct 
  and 
  indirect, 
  will 
  be 
  

   of 
  exceptional 
  interest 
  and 
  importance. 
  There 
  will 
  be 
  advantage 
  

   not 
  unmixed 
  with 
  disadvantage. 
  

  

  (2) 
  There 
  is 
  a 
  possibility 
  worthy 
  of 
  serious 
  inquiry 
  that 
  some 
  

   provisions 
  may 
  be 
  made 
  to 
  lessen 
  the 
  incidental 
  injury 
  to 
  fish 
  life. 
  

  

  (3) 
  The 
  dam 
  will 
  afford 
  a 
  unique 
  opportunity 
  for 
  the 
  study 
  of 
  the 
  

   movement 
  of 
  fishes 
  in 
  the 
  river, 
  if 
  systematic 
  and 
  continuous 
  observa- 
  

   tions 
  be 
  undertaken 
  in 
  the 
  early 
  spring 
  and 
  continued 
  through 
  the 
  

   summer. 
  

  

  (4) 
  The 
  new-formed 
  lake 
  offers 
  an 
  equally 
  unicjue 
  opportunity 
  for 
  

   the 
  study 
  of 
  the 
  development 
  of 
  the 
  proper 
  biological 
  conditions 
  for 
  

   fish 
  life. 
  It 
  would 
  be 
  not 
  only 
  a 
  fascinating 
  study, 
  but 
  one 
  of 
  most 
  

   vital 
  significance, 
  to 
  trace 
  the 
  development 
  of 
  this 
  lake 
  from 
  a 
  con- 
  

   dition 
  of 
  infancy 
  to 
  one 
  of 
  maturity, 
  were 
  there 
  available 
  the 
  means 
  

   necessary 
  for 
  such 
  an 
  investigation. 
  

  

  (5) 
  The 
  opportunity 
  afforded 
  by 
  this 
  new 
  body 
  of 
  water 
  brings 
  the 
  

   responsibility 
  of 
  taking 
  defmite 
  measures 
  for 
  stocking 
  it 
  with 
  suitable 
  

   fish 
  and 
  mussels; 
  and 
  scarcely 
  less 
  important 
  is 
  the 
  introduction 
  of 
  

   suitfible 
  aquatic 
  vegetation 
  which 
  otherwise, 
  as 
  our 
  experience 
  at 
  

   Fairport 
  indicates'' 
  wiU 
  be 
  slow 
  to 
  find 
  a 
  desirable 
  development. 
  

  

  o 
  By 
  "river-lake," 
  I 
  mean 
  such 
  a 
  body 
  of 
  relatively 
  still 
  water 
  as 
  would 
  ordinarily 
  be 
  called 
  a 
  lake, 
  

   which 
  is 
  yet 
  intimately 
  connected 
  with 
  a 
  river, 
  either 
  as 
  interpolated 
  in 
  the 
  course 
  of 
  the 
  river, 
  or 
  as 
  an 
  

   arm 
  of 
  a 
  river. 
  The 
  conditions 
  in 
  a 
  body 
  of 
  this 
  kind 
  may 
  be 
  characteristic. 
  A\ith 
  the 
  opportunity 
  for 
  

   the 
  internal 
  cuculation, 
  plankton 
  conditions 
  and 
  conununity 
  life, 
  corresponding 
  in 
  some 
  degree 
  to 
  typical 
  

   lakes, 
  there 
  are 
  combined 
  in 
  a 
  measure 
  the 
  features 
  of 
  circulation 
  and 
  regular 
  renewal 
  of 
  water 
  correspond- 
  

   mg 
  more 
  nearly 
  to 
  usual 
  river 
  conditions. 
  Illustrations 
  are 
  Cross 
  and 
  Pokegama 
  Lakes 
  m 
  Minnesota, 
  

   Lake 
  Pepm 
  and 
  Lake 
  St. 
  Croix, 
  and 
  in 
  a 
  smaller 
  way. 
  Rice 
  Lake 
  at 
  La 
  Cro.sse, 
  A\'is., 
  which 
  is 
  between 
  

   the 
  Mississippi 
  and 
  Black 
  Rivers 
  and 
  comiected 
  with 
  both. 
  Lake 
  and 
  river 
  faunas 
  are 
  generally 
  quite 
  

   distinct 
  in 
  character. 
  In 
  fact, 
  it 
  is 
  rare 
  for 
  a 
  lake 
  to 
  yield 
  commercial 
  nuissels. 
  In 
  the 
  instances 
  just 
  men- 
  

   tioned 
  we 
  find, 
  however, 
  characteristic 
  river 
  mussels, 
  and, 
  what 
  is 
  more 
  striking, 
  we 
  find 
  that 
  a 
  species 
  

   such 
  as 
  the 
  so-called 
  fat 
  mucket 
  {L. 
  lutcola), 
  which 
  is 
  generally 
  abundant 
  and 
  worthless 
  in 
  true 
  lakes, 
  is 
  in 
  

   ttiese 
  river-lakes 
  abundant 
  and 
  valuable— 
  that 
  is, 
  it 
  has 
  a 
  shell 
  of 
  such 
  thickness 
  and 
  form 
  as 
  to 
  be 
  excep- 
  

   tionally 
  useful 
  for 
  buttons. 
  The 
  adaptations 
  of 
  this 
  species 
  is 
  an 
  interesting 
  chapter 
  in 
  itself. 
  No 
  other 
  

   species 
  of 
  mussel 
  is 
  so 
  generally 
  worthless 
  and, 
  at 
  the 
  same 
  time, 
  so 
  exceptionally 
  valuable 
  and 
  abundant 
  

   in 
  particular 
  regions. 
  Are 
  its 
  good 
  qualities 
  attributable 
  to 
  the 
  unusual 
  combination 
  of 
  river 
  and 
  lake 
  

   conditions, 
  or 
  are 
  they 
  characteristic 
  of 
  a 
  geographic 
  region? 
  Will 
  the 
  same 
  species 
  attaui 
  importance 
  in 
  

   Lake 
  Cooper? 
  When 
  the 
  latter 
  question 
  is 
  answered, 
  as 
  it 
  wUl 
  be 
  in 
  course 
  of 
  a 
  few 
  years, 
  the 
  answer 
  to 
  

   the 
  former 
  question 
  v 
  ill 
  be 
  supplied 
  at 
  the 
  same 
  timo. 
  

  

  b 
  The 
  Bureau 
  through 
  the 
  Fairport 
  station 
  has 
  already 
  made 
  some 
  plants 
  of 
  fish 
  and 
  mussels, 
  and 
  since 
  

   this 
  paper 
  has 
  gone 
  to 
  press 
  has 
  undertaken 
  a 
  preliminary 
  study 
  of 
  the 
  plankton 
  of 
  portions 
  of 
  the 
  lake 
  

   with 
  a 
  view 
  of 
  tracing 
  in 
  this 
  and 
  suliscquent 
  years 
  the 
  development 
  of 
  the 
  content 
  of 
  fish 
  food. 
  Further 
  

   oV>servations 
  are 
  inserted 
  in 
  another 
  portion 
  of 
  the 
  paper. 
  

  

  