﻿OYSTEK 
  BOTTOMS 
  OP 
  LAVACA 
  BAY, 
  TEX. 
  41 
  

  

  OYSTER 
  ENEMIES. 
  

  

  Comparatively 
  few 
  oyster 
  enemies 
  were 
  observed 
  during 
  the 
  sur- 
  

   vey 
  and 
  there 
  was 
  but 
  little 
  evidence 
  of 
  any 
  considerable 
  destruction 
  

   of 
  oysters 
  through 
  their 
  agency. 
  Probably 
  more 
  oysters 
  are 
  de- 
  

   stroyed 
  by 
  mud, 
  or 
  through 
  being 
  overgrown 
  and 
  smothered 
  by 
  

   their 
  own 
  kind, 
  than 
  are 
  killed 
  by 
  other 
  marine 
  animals. 
  

  

  Brills 
  or 
  conchs. 
  — 
  There 
  occur 
  in 
  Lavaca 
  Bay 
  two 
  species 
  of 
  these 
  

   marine 
  snails, 
  known 
  to 
  zoologists 
  as 
  Thais 
  hsemastoma 
  Yar.JJoridana 
  

   and 
  Busycon 
  perversum, 
  the 
  former 
  being 
  the 
  more 
  common 
  and 
  

   larger 
  species, 
  one 
  specimen 
  taken 
  measuring 
  over 
  4 
  inches 
  in 
  length. 
  

   Not 
  over 
  two 
  or 
  three 
  dozen 
  of 
  both 
  kinds 
  were 
  found 
  during 
  the 
  

   survey 
  and 
  practically 
  no 
  oysters 
  killed 
  by 
  them 
  were 
  found. 
  These 
  

   drills 
  are 
  essentially 
  salt-water 
  animals 
  and 
  are 
  confined 
  to 
  the 
  

   lower 
  part 
  of 
  the 
  bay. 
  It 
  is 
  commonly 
  supposed 
  by 
  oystermen 
  that 
  

   they 
  secrete 
  an 
  acid 
  by 
  which 
  they 
  perforate 
  the 
  oyster 
  shells 
  by 
  

   solution, 
  but 
  in 
  reality 
  the 
  holes 
  are 
  made 
  mechanically 
  by 
  means 
  

   of 
  a 
  rasp-like 
  tongue 
  which 
  can 
  be 
  protuded 
  from 
  the 
  mouth. 
  

  

  Mussels 
  (Mytilus 
  hamalus). 
  — 
  The 
  mussels 
  found 
  on 
  the 
  oyster 
  

   beds 
  must 
  not 
  be 
  confused 
  with 
  either 
  the 
  large 
  edible 
  sea 
  mussel 
  of 
  

   the 
  Atlantic 
  coast 
  or 
  the 
  fresh-water 
  mussel, 
  which 
  is 
  used 
  for 
  button 
  

   making. 
  So 
  far 
  as 
  is 
  known 
  this 
  species 
  has 
  no 
  present 
  economic 
  

   use, 
  although 
  doubtless 
  it 
  would 
  make 
  a 
  good 
  fertilizer. 
  

  

  Mussels 
  were 
  found 
  very 
  sparingly 
  on 
  the 
  beds 
  of 
  the 
  lower 
  half 
  of 
  

   the 
  bay 
  and 
  none 
  at 
  all 
  were 
  observed 
  below 
  a 
  hne 
  uniting 
  Gallinipper 
  

   and 
  Rhodes 
  Points. 
  From 
  Chicken 
  and 
  Lap 
  Reefs 
  northward 
  they 
  

   became 
  more 
  abundant, 
  and 
  on 
  some 
  beds 
  100 
  or 
  more 
  were 
  found 
  

   within 
  an 
  area 
  of 
  2 
  or 
  3 
  square 
  yards. 
  This 
  increased 
  abundance 
  is 
  

   correlated 
  with 
  the 
  lowered 
  salinity 
  of 
  the 
  water, 
  this 
  mussel 
  being 
  

   an 
  inhabitant 
  of 
  brackish 
  waters. 
  Although 
  this 
  mollusk 
  is 
  classed 
  as 
  

   an 
  oyster 
  enemy, 
  it 
  is 
  not 
  one 
  in 
  the 
  sense 
  of 
  preying 
  on 
  the 
  more 
  valu- 
  

   able 
  shellfish. 
  It 
  is 
  injurious 
  in 
  that 
  it 
  eats 
  the 
  same 
  kind 
  of 
  food 
  as 
  

   the 
  oyster, 
  and 
  therefore 
  lessens 
  the 
  supply 
  for 
  the 
  latter, 
  while 
  at 
  the 
  

   same 
  time 
  its 
  more 
  prohfic 
  growth 
  enables 
  it 
  to 
  cover 
  the 
  latter, 
  inter- 
  

   fere 
  with 
  its 
  growth 
  and 
  eventually 
  to 
  stifle 
  and 
  starve 
  it. 
  

  

  Drumjisli 
  {Pogonias 
  cromis). 
  — 
  The 
  black 
  drum 
  was 
  not 
  observed 
  

   during 
  the 
  survey, 
  nor 
  was 
  it 
  learned 
  that 
  it 
  had 
  ever 
  caused 
  destruc- 
  

   tion 
  in 
  Lavaca 
  Bay. 
  It 
  is 
  mentioned 
  here 
  because 
  it 
  is 
  hkely 
  to 
  

   appear 
  suddenly 
  on 
  any 
  part 
  of 
  the 
  coast 
  and 
  at 
  such 
  times 
  it 
  is 
  often 
  

   very 
  destructive, 
  particularly 
  to 
  the 
  planted 
  oysters 
  of 
  better 
  quality. 
  

   Owing 
  to 
  the 
  clustered 
  growth 
  and 
  sharp 
  edges 
  of 
  the 
  oysters 
  the 
  

   natural 
  beds 
  of 
  Lavaca 
  Bay 
  are 
  not 
  likely 
  to 
  be 
  seriouslj^ 
  injured 
  by 
  

   this 
  fish. 
  

  

  Minor 
  enemies 
  and 
  pests. 
  — 
  The 
  yellow 
  sponge, 
  which 
  overgrows 
  

   the 
  oysters 
  and 
  produces 
  the 
  ''worm-eaten" 
  condition 
  of 
  the 
  shells, 
  

   barnacles 
  which 
  crowd 
  the 
  oysters 
  and 
  roughen 
  the 
  shells, 
  and 
  the 
  

   9497°— 
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