﻿14 
  PROPAGATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  of 
  the 
  mantle 
  and 
  shell 
  are 
  uninjured, 
  the 
  gravid 
  mussel 
  may 
  be 
  kept 
  

   alive 
  out 
  of 
  water 
  several 
  hours, 
  and 
  still 
  longer 
  when 
  kept 
  cool. 
  

   Mussels 
  caught 
  by 
  the 
  "crowfoot" 
  method 
  are 
  more 
  difficult 
  to 
  keep 
  

   because 
  of 
  breaks 
  in 
  the 
  shell. 
  It 
  is 
  difficult 
  to 
  prevent 
  abortion 
  of 
  

   glochidia 
  when 
  a 
  number 
  of 
  mussels 
  are 
  placed 
  together 
  in 
  water 
  even 
  

   though 
  running 
  as 
  from 
  a 
  tap 
  or 
  when 
  the 
  mussels 
  are 
  placed 
  in 
  crates 
  

   in 
  a 
  river. 
  On 
  account 
  of 
  this 
  habit 
  of 
  abortion 
  in 
  Q. 
  pusfvJosa 
  and 
  

   most 
  of 
  the 
  Quadrulas, 
  their 
  transportation 
  and 
  retention 
  is 
  more 
  

   difficult 
  than 
  in 
  the 
  case 
  of 
  the 
  "mucket," 
  Lampsilis 
  ligamentina, 
  and 
  

   the 
  other 
  members 
  of 
  the 
  Lampsilinse 
  that 
  have 
  been 
  propagated 
  arti- 
  

   ficially. 
  In 
  the 
  latter 
  the 
  portion 
  of 
  the 
  gill 
  differentiated 
  for 
  a 
  

   marsupium 
  is 
  relatively 
  so 
  small 
  that 
  the 
  breathing 
  function 
  of 
  the 
  

   gill 
  is 
  little 
  interfered 
  with 
  by 
  the 
  presence 
  of 
  the 
  embryos, 
  while 
  in 
  

   the 
  former 
  the 
  presence 
  of 
  glochidia 
  in 
  all 
  four 
  gills 
  is 
  probably 
  respon- 
  

   sible 
  for 
  this 
  reaction 
  when 
  proper 
  aeration 
  is 
  interfered 
  with 
  by 
  

   crowding 
  or 
  otherwise. 
  

  

  Propagation. 
  — 
  This 
  species 
  of 
  w^arty-back 
  is 
  one 
  of 
  the 
  most 
  valu- 
  

   able 
  of 
  the 
  pearly 
  mussels 
  used 
  in 
  the 
  button 
  industry, 
  so 
  that 
  any 
  

   practical 
  means 
  of 
  increasing 
  the 
  supply 
  would 
  be 
  welcomed. 
  The 
  

   determination 
  of 
  the 
  host 
  fish 
  furnishes 
  the 
  means 
  of 
  employing 
  the 
  

   method 
  of 
  propagation 
  that 
  has 
  proved 
  so 
  successful 
  in 
  the 
  case 
  of 
  

   Lampsilis 
  ligamentina 
  and 
  others 
  of 
  that 
  genus. 
  

  

  In 
  the 
  catfish 
  we 
  seem 
  to 
  have 
  a 
  fish 
  almost 
  ideal 
  for 
  the 
  application 
  

   of 
  this 
  method. 
  It 
  is 
  abundant 
  and 
  hardy, 
  thus 
  meeting 
  the 
  condi- 
  

   tions 
  required 
  by 
  the 
  method, 
  i. 
  e., 
  the 
  securing 
  of 
  many 
  fish 
  and 
  the 
  

   ability 
  of 
  the 
  fish 
  to 
  withstand 
  the 
  handling 
  and 
  confinement 
  incident 
  

   to 
  the 
  process 
  of 
  infection 
  with 
  glochidia. 
  The 
  method 
  as 
  employed 
  

   for 
  the 
  past 
  three 
  years 
  has 
  had 
  some 
  modifications. 
  The 
  fish, 
  after 
  

   seining, 
  in 
  one 
  instance, 
  were 
  brought 
  to 
  a 
  central 
  station 
  for 
  infec- 
  

   tion; 
  in 
  the 
  other 
  they 
  were 
  infected 
  in 
  the 
  field 
  and 
  immediately 
  

   released. 
  Some 
  fish 
  will 
  not 
  survive 
  even 
  the 
  latter 
  very 
  limited 
  

   amount 
  of 
  handling 
  or 
  confinement; 
  for 
  example, 
  the 
  herring, 
  Pom- 
  

   olobus 
  chrysocJiloris, 
  which 
  has 
  been 
  determined 
  as 
  the 
  host 
  for 
  the 
  

   niggerhead, 
  Q. 
  ehena 
  (Surber, 
  1913). 
  The 
  power 
  of 
  catfish 
  to 
  survive 
  

   removal 
  from 
  water 
  is 
  remarkable 
  and 
  this 
  hardihood 
  is 
  an 
  important 
  

   feature, 
  since 
  the 
  breeding 
  period 
  for 
  these 
  mussels 
  is 
  July 
  and 
  

   August, 
  when 
  the 
  mortality 
  is 
  highest 
  among 
  fish 
  in 
  captivity. 
  

  

  A 
  third 
  modification 
  of 
  this 
  method, 
  the 
  propagation 
  of 
  musseL 
  in 
  

   ponds 
  or 
  artificial 
  streams 
  after 
  infection, 
  may 
  prove 
  to 
  be 
  very 
  practi- 
  

   cable, 
  as 
  some 
  mussels 
  seem 
  to 
  prosper 
  under 
  these 
  conditions. 
  If, 
  in 
  

   the 
  case 
  of 
  the 
  commercial 
  species, 
  this 
  method 
  proves 
  successful 
  it 
  

   win 
  offer 
  the 
  advantage 
  of 
  greater 
  certainty 
  in 
  results. 
  By 
  the 
  

   method 
  in 
  use 
  at 
  present, 
  the 
  young 
  mussel 
  is 
  released 
  at 
  a 
  stage 
  when 
  

   it 
  is 
  quit(> 
  at 
  the 
  mercy 
  of 
  its 
  enemies 
  and 
  results 
  are 
  scarcely 
  ascer- 
  

   tainable. 
  If 
  protected 
  until 
  a 
  few 
  miUimeters 
  long, 
  when 
  a 
  heavy 
  

  

  