﻿WATER-POWER 
  DEVELOPMENT 
  IN 
  THE 
  MISSISSIPPI. 
  7 
  

  

  whether 
  by 
  natural 
  or 
  artificial 
  means, 
  of 
  an 
  immense 
  pool, 
  where 
  

   practically 
  fixed 
  and 
  dependable 
  conditions 
  can 
  be 
  found, 
  is 
  not 
  to 
  be 
  

   lightly 
  esteemed. 
  

  

  It 
  becomes 
  of 
  greater 
  importance 
  that 
  the 
  possible 
  disadvantages 
  

   incident 
  to 
  such 
  an 
  interpolation 
  should 
  be 
  eliminated 
  as 
  far 
  as 
  

   possible. 
  Lake 
  Pepin 
  of 
  the 
  upper 
  ^Mississippi, 
  a 
  virtual 
  lake 
  of 
  

   natural 
  origin, 
  is 
  a 
  great 
  natural 
  fish 
  reserve 
  into 
  and 
  out 
  of 
  which 
  

   fish 
  may 
  proceed 
  at 
  will 
  at 
  either 
  end. 
  Lake 
  Cooper 
  of 
  the 
  middle 
  

   region 
  of 
  the 
  Mississippi 
  is 
  an 
  artificial 
  lake 
  into 
  and 
  out 
  of 
  which 
  

   fish 
  may 
  pass 
  unchecked 
  in 
  only 
  one 
  direction. 
  

  

  Any 
  student 
  of 
  fisheries 
  will 
  at 
  first 
  glance 
  make 
  a 
  further 
  com- 
  

   parison 
  of 
  these 
  two 
  expansions 
  of 
  the 
  Mississippi. 
  The 
  body 
  of 
  Lake 
  

   Pepin 
  has 
  a 
  comparatively 
  straight 
  shore 
  line 
  and 
  in 
  some 
  places 
  is 
  

   bounded 
  by 
  steep 
  bluffs; 
  there 
  is 
  a 
  relative 
  absence 
  of 
  slues 
  and 
  shal- 
  

   lows 
  favorable 
  for 
  aquatic 
  vegetation. 
  Above 
  and 
  below 
  Lake 
  Pepin, 
  

   however, 
  there 
  are 
  many 
  slues 
  and 
  bayous 
  which 
  offer 
  favorable 
  con- 
  

   ditions 
  for 
  the 
  breeding 
  of 
  fishes, 
  and 
  undoubtedly 
  the 
  fish 
  fife 
  of 
  the 
  

   lake 
  is 
  continually 
  replenished 
  from 
  these 
  sources. 
  Lake 
  Cooper, 
  on 
  

   the 
  other 
  hand, 
  has 
  few 
  bluft' 
  shores, 
  and 
  throughout 
  its 
  course, 
  except 
  

   very 
  near 
  Keokuk, 
  there 
  are 
  many 
  favorable 
  bayous, 
  creeks, 
  and 
  

   expansions 
  over 
  former 
  agricultural 
  or 
  swampy 
  flats. 
  As 
  regards 
  the 
  

   proportion 
  of 
  deeper 
  waters 
  preferred 
  by 
  some 
  species 
  of 
  fish, 
  the 
  two 
  

   lakes 
  might 
  compare 
  more 
  closely, 
  except 
  that 
  the 
  deep 
  water 
  in 
  Lake 
  

   Cooper 
  is 
  at 
  one 
  end 
  and 
  is 
  loss 
  extensive. 
  

  

  The 
  relation 
  of 
  such 
  developments 
  to 
  mussel 
  life 
  may 
  be 
  briefly 
  

   explained. 
  The 
  very 
  young 
  fresh-water 
  mussels, 
  with 
  rare 
  exception, 
  

   when 
  first 
  hberated 
  from 
  the 
  incubation 
  pouches 
  of 
  the 
  parent, 
  

   must 
  become 
  parasitic 
  upon 
  fishes 
  in 
  order 
  to 
  pass 
  through 
  the 
  next 
  

   stage 
  of 
  their 
  existence. 
  To 
  this 
  end, 
  if 
  the 
  chance 
  oflers 
  after 
  

   hberation, 
  the 
  young 
  mussels, 
  or 
  glocliidia, 
  as 
  they 
  are 
  called 
  in 
  this 
  

   stage, 
  attach 
  themselves 
  to 
  the 
  gills, 
  fuis, 
  or 
  scales 
  of 
  a 
  fish. 
  The 
  

   mussels 
  of 
  economic 
  importance 
  attach 
  themselves 
  almost 
  exclu- 
  

   sively 
  to 
  the 
  gills. 
  In 
  attaching 
  or 
  biting 
  on 
  the 
  fish 
  a 
  very 
  slight 
  

   wound 
  seems 
  to 
  be 
  caused, 
  wliich 
  begins 
  at 
  once 
  to 
  heal 
  over; 
  but 
  

   in 
  the 
  process 
  of 
  mending, 
  the 
  glochidium 
  is 
  overgrown 
  and 
  thus 
  

   inclosed 
  within 
  the 
  tissues 
  of 
  the 
  fish. 
  The 
  mussel 
  is 
  now 
  actuaUy 
  an 
  

   internal 
  parasite, 
  in 
  which 
  condition 
  it 
  remains 
  for 
  a 
  period 
  of 
  two 
  

   weeks, 
  more 
  or 
  less. 
  It 
  is 
  thus 
  conveyed 
  wherever 
  the 
  fish 
  goes, 
  

   until, 
  when 
  the 
  proper 
  stage 
  of 
  development 
  is 
  reached, 
  it 
  frees 
  

   itself 
  from 
  the 
  host 
  and 
  falls 
  to 
  the 
  bottom; 
  if 
  through 
  a 
  favorable 
  

   fortune 
  it 
  finds 
  suitable 
  lodgment, 
  it 
  continues 
  its 
  growth 
  to 
  form 
  an 
  

   adult 
  mussel. 
  Owing 
  to 
  this 
  fact 
  of 
  active 
  transportation 
  by 
  the 
  

   fish, 
  a 
  mussel 
  born 
  of 
  parents 
  in 
  one 
  part 
  of 
  the 
  river 
  may 
  conclude 
  

   its 
  development 
  in 
  another 
  region, 
  even 
  at 
  points 
  far 
  upstream 
  

  

  