﻿12 
  MUSSELS 
  IN 
  TKIBUTAEIES 
  OF 
  UPPEE 
  MISSOURI 
  RIVER. 
  

  

  NATURAL 
  PROPAGATION 
  OF 
  MUSSELS 
  IN 
  REI^TION 
  TO 
  FLOOD 
  STAGES 
  

  

  IN 
  THE 
  JAMES 
  RIVER. 
  

  

  From 
  the 
  account 
  of 
  the 
  dramage 
  area 
  just 
  given 
  it 
  is 
  evident 
  

   that 
  the 
  ground 
  waters, 
  although 
  plentiful 
  at 
  great 
  deptlis, 
  can 
  sup- 
  

   ply 
  but 
  a 
  small 
  flow 
  to 
  the 
  river. 
  Wliile, 
  therefore, 
  the 
  river 
  may 
  at 
  

   aU 
  tmies 
  cover 
  sufficient 
  bottom 
  to 
  support 
  an 
  abundance 
  of 
  mussels, 
  

   it 
  can 
  have 
  a 
  considerable 
  volume 
  only 
  when 
  there 
  is 
  a 
  direct 
  inflow 
  

   of 
  surface 
  waters 
  after 
  periods 
  of 
  rainfall. 
  It 
  is 
  even 
  probable 
  that 
  

   light 
  rains 
  are 
  so 
  completely 
  absorbed 
  by 
  the 
  loose 
  dry 
  soils 
  that 
  the 
  

   river 
  is 
  only 
  slightly 
  affected 
  by 
  them. 
  

  

  The 
  effect 
  of 
  such 
  conditions 
  upon 
  the 
  stages 
  of 
  the 
  river 
  is 
  of 
  

   particular 
  interest 
  in 
  connection 
  with 
  the 
  observations 
  regarding 
  the 
  

   mussels. 
  The 
  fact 
  that 
  scarcely 
  any 
  small 
  mussels 
  were 
  found 
  led 
  to 
  

   the 
  inference, 
  as 
  previously 
  mentioned, 
  that 
  the 
  opportunity 
  for 
  

   natural 
  propagation 
  of 
  the 
  mussels 
  occurred 
  only 
  at 
  irregular 
  intervals. 
  

  

  From 
  the 
  data 
  regarding 
  the 
  average 
  river 
  stages 
  given 
  in 
  the 
  f 
  ol- 
  

   lo^^'ing 
  table, 
  ° 
  it 
  appears 
  that 
  while 
  the 
  James 
  River 
  is 
  occasionally 
  

   subject 
  to 
  high 
  stages 
  it 
  orcUnarily 
  maintains 
  a 
  very 
  low 
  level. 
  Thus, 
  

   during 
  the 
  entire 
  year 
  1911 
  the 
  monthly 
  average 
  stage 
  did 
  not 
  attain 
  

   3 
  feet 
  in 
  any 
  month, 
  and 
  exceeded 
  1 
  foot 
  in 
  only 
  three 
  months, 
  viz, 
  

   February 
  (i.l 
  feet), 
  April 
  (2.6 
  feet), 
  and 
  May 
  (2.2 
  feet). 
  The 
  con- 
  

   ditions 
  in 
  1913, 
  up 
  to 
  September, 
  were 
  nearly 
  the 
  same, 
  the 
  spring 
  

   stage 
  being 
  just 
  a 
  Uttle 
  later. 
  On 
  the 
  other 
  hand, 
  during 
  the 
  three 
  

   preceding 
  jears 
  (1908-1910) 
  higher 
  averages 
  were 
  made, 
  particularly 
  

   dining 
  1909 
  and 
  1910, 
  when 
  monthly 
  averages 
  of 
  11.7 
  feet 
  and 
  10.9 
  

   feet, 
  respectively, 
  are 
  found 
  in 
  March. 
  The 
  highest 
  recorded 
  stage, 
  

   14.6 
  feet, 
  was 
  made 
  March 
  15, 
  1910. 
  

  

  If 
  the 
  natural 
  propagation 
  of 
  mussels 
  in 
  the 
  river 
  depends 
  upon 
  a 
  

   run 
  of 
  fishes 
  during 
  high 
  stages, 
  it 
  is 
  evident 
  that 
  favorable 
  conditions 
  

   had 
  not 
  occurred 
  since 
  1910, 
  and 
  consequently 
  we 
  could 
  not 
  expect 
  

   to 
  find 
  smaU 
  mussels 
  in 
  1913, 
  except 
  as 
  they 
  might 
  have 
  developed 
  

   in 
  favored 
  spots 
  where 
  fish 
  were 
  left. 
  It 
  is 
  of 
  interest 
  that 
  from 
  

   observations 
  of 
  the 
  mussels 
  it 
  should 
  have 
  been 
  assumed 
  that 
  no 
  

   flood 
  stages 
  of 
  the 
  river 
  had 
  occurred 
  recently, 
  and 
  that 
  the 
  records 
  

   of 
  river 
  stages, 
  subsequently 
  obtained, 
  should 
  have 
  offered 
  confirma- 
  

   tion 
  of 
  this 
  presumption. 
  

  

  Since 
  most 
  of 
  the 
  species 
  of 
  mussels 
  are 
  in 
  an 
  early 
  stage 
  parasitic 
  

   upon 
  fish 
  and 
  remain 
  in 
  parasitism 
  for 
  a 
  period 
  of 
  time, 
  it 
  follows 
  

   that 
  for 
  a 
  particular 
  bed 
  of 
  mussels 
  to 
  be 
  propagated 
  the 
  fish 
  must 
  

   either 
  come 
  to 
  that 
  bed 
  infected 
  with 
  mussels, 
  or 
  else 
  they 
  must 
  be 
  

   on 
  the 
  bed 
  when 
  mussels 
  are 
  breeding, 
  become 
  infected 
  from 
  that 
  

   bed, 
  and 
  remain 
  or 
  return 
  to 
  drop 
  the 
  mussels 
  in 
  the 
  same 
  vicinity 
  

  

  a 
  These 
  data 
  were 
  kindly 
  supplied 
  by 
  Mr. 
  S. 
  W. 
  Glenn, 
  section 
  director 
  in 
  the 
  Climatological 
  Service 
  of 
  

   the 
  Weather 
  Bureau, 
  Huron, 
  S. 
  Dak. 
  

  

  