﻿MUSSEL 
  EESOUKCES 
  OF 
  THE 
  ILLINOIS 
  RIVER. 
  47 
  

  

  taken, 
  especially 
  at 
  Peoria 
  and 
  Meredosia; 
  this 
  is 
  a 
  remarkable 
  con- 
  

   dition 
  for 
  so 
  muddy 
  a 
  river 
  as 
  the 
  Illinois. 
  This 
  pocketbook, 
  though 
  

   inclined 
  to 
  be 
  brittle, 
  is 
  usually 
  good 
  button 
  material. 
  

  

  SUMMARY 
  AND 
  CONCLUSIONS. 
  

  

  The 
  Illinois 
  river 
  is 
  273 
  miles 
  in 
  length, 
  and, 
  from 
  a 
  mussel 
  fisher- 
  

   man's 
  point 
  of 
  view, 
  it 
  is 
  one 
  of 
  the 
  most 
  important 
  tributaries 
  of 
  

   the 
  upper 
  Mssissippi. 
  

  

  Sewage 
  pollution, 
  with 
  perhaps 
  one 
  or 
  two 
  exceptions, 
  does 
  not 
  

   appear 
  to 
  have 
  decreased 
  the 
  abundance 
  or 
  quahty 
  of 
  the 
  shells 
  

   within 
  the 
  last 
  180 
  miles 
  of 
  the 
  river. 
  

  

  The 
  dip 
  net 
  is 
  used 
  almost 
  exclusively 
  in 
  the 
  Peoria 
  Lake 
  district 
  

   and 
  a 
  few 
  other 
  places 
  where 
  similar 
  lakelike 
  conditions 
  exist. 
  

  

  The 
  price 
  per 
  ton 
  of 
  the 
  river 
  run 
  of 
  commercial 
  shells 
  during 
  1912 
  

   was 
  $12 
  to 
  $13. 
  

  

  Some 
  excellent 
  pearls 
  have 
  been 
  found, 
  ranging 
  in 
  value 
  from 
  a 
  

   few 
  dollars 
  to 
  $2,700. 
  Slugs 
  do 
  not 
  average 
  more 
  than 
  one-half 
  

   ounce 
  per 
  ton 
  of 
  shells. 
  

  

  The 
  laws 
  relating 
  to 
  mussel 
  fishery 
  have 
  been 
  generally 
  observed. 
  

  

  There 
  are 
  15 
  button 
  or 
  blank 
  factories, 
  with 
  about 
  250 
  machines, 
  

   along 
  the 
  river. 
  The 
  raw 
  material 
  is 
  being 
  better 
  utihzed 
  than 
  

   formerly. 
  

  

  The 
  abundance 
  of 
  dead 
  shells 
  on 
  many 
  of 
  the 
  mussel 
  beds 
  may 
  be 
  

   due 
  in 
  part 
  to 
  the 
  lack 
  of 
  erosion 
  of 
  the 
  water 
  and 
  to 
  the 
  injurious 
  

   effects 
  of 
  the 
  crowfoot 
  hooks. 
  

  

  The 
  levees 
  which 
  have 
  been 
  heretofore 
  and 
  are 
  now 
  being 
  con- 
  

   structed, 
  particularly 
  in 
  the 
  lower 
  stretches 
  of 
  the 
  river, 
  reduce 
  to 
  a 
  

   large 
  extent 
  the 
  breeding 
  grounds 
  of 
  the 
  valuable 
  species 
  of 
  fishes 
  

   and 
  incidentally 
  affect 
  the 
  future 
  supply 
  of 
  the 
  mussels. 
  During 
  

   their 
  early 
  life 
  mussels 
  are 
  parasites 
  upon 
  fishes 
  for 
  a 
  period 
  of 
  from 
  

   two 
  to 
  six 
  weeks, 
  and 
  if 
  the 
  fish 
  supply 
  is 
  greatly 
  reduced 
  it 
  is 
  readily 
  

   seen 
  that 
  the 
  mussel 
  supply 
  mil 
  also 
  be 
  materially 
  reduced. 
  

  

  The 
  washboard, 
  or 
  blue-point 
  (Quadrula), 
  group 
  of 
  mussels 
  pre- 
  

   dominates 
  in 
  the 
  IlUnois. 
  The 
  slow 
  current, 
  mud 
  bottoms, 
  good 
  

   average 
  depth 
  of 
  water, 
  and 
  large 
  fish 
  resources 
  all 
  tend 
  to 
  make 
  the 
  

   river 
  an 
  ideal 
  one 
  for 
  this 
  group. 
  The 
  niggerheads 
  (ebena), 
  although 
  

   apparently 
  never 
  very 
  abundant, 
  have 
  become 
  greatly 
  reduced 
  in 
  

   numbers, 
  from 
  a 
  cause 
  not 
  definitely 
  determined. 
  The 
  old 
  wash- 
  

   boards 
  Qieros) 
  in 
  some 
  places, 
  as 
  at 
  Quiver 
  Lake 
  above 
  Havana, 
  have 
  

   been 
  killed, 
  though 
  the 
  present 
  conditions 
  there 
  appear 
  to 
  be 
  more 
  

   favorable. 
  

  

  The 
  mucket 
  (Lampsilis) 
  group 
  is 
  found 
  scattered 
  in 
  small 
  quanti- 
  

   ties 
  throughout 
  the 
  entire 
  river, 
  but 
  more 
  abundantly 
  in 
  Peoria 
  Lake 
  

   and 
  the 
  lower 
  stretches. 
  

  

  