﻿208 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  beds 
  gave 
  no 
  evidence 
  of 
  an 
  erosion 
  of 
  the 
  bottom. 
  Even 
  the 
  light 
  

   empty 
  shells 
  on 
  its 
  surface 
  were 
  not 
  moved 
  to 
  any 
  extent 
  by 
  the 
  cur- 
  

   rents, 
  so 
  that 
  clams 
  in 
  these 
  beds 
  nowhere 
  seemed 
  to 
  be 
  washed 
  out 
  

   or 
  covered 
  with 
  sand. 
  There 
  were 
  places, 
  it 
  is 
  true, 
  where 
  they 
  wore 
  

   so 
  closely 
  crowded 
  as 
  nearly 
  to 
  touch 
  each 
  other, 
  but 
  over 
  the 
  greater 
  

   part 
  of 
  the 
  beds 
  there 
  was 
  ample 
  space 
  for 
  all. 
  Yet 
  ever3'where 
  the 
  

   same 
  destruction 
  occurred. 
  Mead's 
  explanation 
  did 
  not 
  apply 
  here. 
  

  

  Almost 
  everywhere 
  among 
  the 
  empty 
  shells 
  on 
  the 
  surface 
  living 
  

   clams 
  were 
  found. 
  Even 
  when 
  20 
  mm. 
  in 
  length, 
  a 
  clam 
  is 
  ordinarily 
  

   able 
  to 
  cover 
  itself 
  in 
  the 
  course 
  of 
  a 
  few 
  minutes, 
  and 
  smaller 
  ones 
  

   are 
  more 
  active 
  than 
  the 
  larger. 
  Small 
  clams 
  have 
  been 
  described 
  in 
  

   a 
  previous 
  paper 
  as 
  being 
  restless 
  and 
  as 
  having 
  the 
  habit 
  of 
  coming 
  

   out 
  of 
  their 
  burrows, 
  wandering 
  for 
  short 
  distances, 
  and 
  again 
  digging 
  

   into 
  the 
  sand. 
  Yet 
  these 
  individuals 
  among 
  the 
  empty 
  shells 
  usually 
  

   seem 
  to 
  be 
  inert. 
  

  

  The 
  following 
  explanation 
  is 
  offered 
  for 
  the 
  destruction 
  on 
  these 
  

   beds. 
  The 
  small 
  clams 
  are 
  constantly 
  coming 
  to 
  the 
  surface 
  of 
  the 
  

   bottom. 
  When 
  exposed 
  they 
  are 
  subject 
  to 
  the 
  attack 
  of 
  starfish, 
  

   crabs, 
  and 
  fishes, 
  and 
  though 
  these 
  enemies 
  were 
  very 
  scarce 
  here, 
  

   some 
  clams 
  may 
  have 
  been 
  destroyed 
  by 
  them. 
  Because 
  so 
  many 
  

   of 
  those 
  \y'ing 
  among 
  the 
  empty 
  shells 
  could 
  not 
  be 
  revived 
  on 
  being 
  

   removed 
  to 
  what 
  appeared 
  to 
  be 
  more 
  favorable 
  localities, 
  but 
  re- 
  

   mained 
  motionless 
  until 
  they 
  died, 
  we 
  ma}^ 
  suppose 
  them 
  to 
  have 
  been 
  

   greatly 
  exhausted 
  from 
  lack 
  of 
  food. 
  The 
  wandering 
  habit 
  of 
  the 
  

   small 
  clam 
  will 
  account 
  for 
  the 
  appearance 
  of 
  so 
  man}' 
  dead 
  shells 
  on 
  

   the 
  surface 
  where 
  there 
  is 
  no 
  crowding 
  or 
  washing 
  out. 
  It 
  was 
  stated 
  

   that 
  a 
  very 
  large 
  number 
  died 
  in 
  the 
  burrows 
  also. 
  If 
  lack 
  of 
  food 
  

   is 
  the 
  explanation 
  for 
  the 
  beginning 
  of 
  the 
  destruction, 
  however, 
  there 
  

   must 
  have 
  been 
  a 
  time, 
  after 
  the 
  death 
  of 
  a 
  certain 
  proportion 
  of 
  the 
  

   whole 
  number, 
  when 
  food 
  in 
  the 
  water 
  was 
  suflicient 
  for 
  the 
  remainder. 
  

   As 
  these 
  grew 
  and 
  each 
  demanded 
  more 
  nourishment, 
  others 
  would 
  

   die, 
  until 
  a 
  new 
  equilibrium 
  was 
  established. 
  Instead, 
  almost 
  com- 
  

   plete 
  annihilation 
  occurred. 
  

  

  Another 
  factor 
  may 
  have 
  entered 
  into 
  the 
  problem. 
  The 
  contami- 
  

   nation 
  of 
  the 
  water, 
  by 
  the 
  bodies 
  of 
  so 
  many 
  dead, 
  finally 
  may 
  have 
  

   caused 
  the 
  death 
  of 
  all. 
  This 
  is 
  suggested 
  because 
  on 
  several 
  arti- 
  

   ficial 
  beds 
  in 
  which 
  the 
  clams 
  were 
  closel}^ 
  crowded 
  the 
  destruction 
  of 
  

   all 
  seemed 
  to 
  occur 
  from 
  this 
  cause. 
  

  

  The 
  assumption 
  that 
  lack 
  of 
  food 
  and 
  the 
  spread 
  of 
  infection 
  from 
  

   dead 
  clams 
  were 
  the 
  causes 
  of 
  the 
  extermination 
  seems 
  to 
  be 
  confirmed 
  

   by 
  the 
  fact 
  that 
  death 
  apparently 
  occurred 
  first 
  where 
  clams 
  were 
  most 
  

   crowded, 
  and 
  spread 
  from 
  those 
  points. 
  By 
  September 
  1 
  almost 
  ever}'^ 
  

   clam 
  was 
  dead 
  at 
  the 
  lower 
  ends 
  of 
  the 
  beds, 
  nearest 
  the 
  mouth 
  of 
  the 
  

   bay, 
  where 
  they 
  had 
  been 
  most 
  closely 
  set, 
  while 
  at 
  the 
  upper 
  ends, 
  

   where 
  they 
  were 
  scattered, 
  several 
  still 
  survived. 
  

  

  