﻿284 
  REPORT 
  OF 
  COMMISSIONER 
  OP 
  PISH 
  AND 
  FISHERIES. 
  

  

  exposed 
  to 
  it, 
  except 
  when 
  the 
  currents 
  are 
  sufficient 
  to 
  exert 
  a 
  scouring 
  

   influence. 
  

  

  Large 
  oysters 
  are 
  not 
  so 
  susceptible 
  as 
  small 
  ones 
  to 
  the 
  effects 
  of 
  

  

  mud, 
  but 
  even 
  those 
  full 
  grown 
  may 
  be 
  stifled 
  or 
  buried 
  by 
  the 
  rapid 
  

  

  deposit 
  of 
  mud 
  or 
  sediment, 
  whether 
  this 
  be 
  of 
  organic 
  or 
  inorganic 
  

  

  origin. 
  Freshets 
  and 
  heavy 
  seas 
  often 
  cause 
  great 
  damage 
  by 
  the 
  

  

  .amount 
  of 
  mud, 
  sand, 
  and 
  other 
  debris 
  which 
  they 
  carrj^ 
  upon 
  the 
  beds. 
  

  

  The 
  question 
  of 
  the 
  physical 
  characters 
  of 
  a 
  suitable 
  bottom 
  for 
  

   oyster-culture 
  is 
  considered 
  in 
  another 
  connection. 
  

  

  TIDES 
  AND 
  CURRENTS. 
  

  

  Tides 
  and 
  currents 
  are 
  important 
  factors 
  in 
  the 
  growth 
  and 
  culture 
  

   of 
  the 
  oyster. 
  They 
  bring 
  about 
  the 
  aeration 
  of 
  the 
  water 
  and 
  oxida- 
  

   tion 
  of 
  its 
  dead 
  organic 
  ingredients; 
  they 
  have 
  a 
  scouring 
  action 
  upon 
  

   the 
  bottom 
  and 
  thereby 
  cleanse 
  the 
  cultch, 
  and 
  at 
  the 
  same 
  time 
  serve 
  

   as 
  the 
  vehicles 
  for 
  the 
  transportation 
  of 
  food, 
  of 
  the 
  genital 
  products, 
  

   and 
  of 
  the 
  young. 
  Stagnant 
  water 
  tends 
  to 
  become 
  exhausted 
  of 
  its 
  

   oxygen; 
  it 
  is 
  heated 
  by 
  the 
  sun, 
  and 
  the 
  contained 
  organic 
  matter 
  

   undergoing 
  death 
  and 
  decomposition 
  causes 
  it 
  to 
  become 
  foul 
  and 
  fatal 
  

   to 
  the 
  oysters 
  in 
  the 
  vicinity. 
  With 
  currents, 
  however, 
  a 
  fresh 
  supply 
  

   of 
  oxygen 
  is 
  constantly 
  being 
  supplied 
  for 
  respiration 
  and 
  for 
  the 
  

   combustion 
  of 
  the 
  effete 
  matter, 
  which 
  is 
  thus 
  rendered 
  harmless. 
  

  

  Over 
  densely-populated 
  beds 
  the 
  food 
  supply, 
  unless 
  unusually 
  pro- 
  

   lific, 
  as 
  in 
  claires, 
  would 
  in 
  time 
  become 
  exhausted. 
  The 
  oyster 
  can 
  

   not, 
  of 
  course, 
  change 
  its 
  location, 
  but 
  the 
  same 
  purpose 
  is 
  subserved 
  

   by 
  currents 
  constantly 
  bringing 
  a 
  fresh 
  supply 
  of 
  food-laden 
  water 
  

   within 
  the 
  influence 
  of 
  the 
  ciliary 
  action 
  by 
  which 
  the 
  oyster 
  captures 
  

   its 
  food. 
  

  

  The 
  genital 
  products 
  of 
  the 
  oyster, 
  both 
  male 
  and 
  female, 
  are 
  simi)ly 
  

   discharged 
  into 
  the 
  surrounding 
  water. 
  The 
  eggs 
  are 
  absolutely 
  immo- 
  

   bile, 
  and 
  while 
  the 
  spermatozoa, 
  or 
  male 
  elements, 
  possess 
  the 
  power 
  of 
  

   locomotion 
  to 
  some 
  extent, 
  they 
  are 
  obviously 
  incapable 
  of 
  moving 
  very 
  

   far 
  during 
  the 
  limited 
  period 
  of 
  their 
  mobility. 
  In 
  densely-crowded 
  beds 
  

   no 
  doubt 
  a 
  considerable 
  proportion 
  of 
  the 
  eggs 
  may 
  become 
  fertilized 
  

   even 
  without 
  the 
  agency 
  of 
  currents, 
  but 
  where, 
  as 
  upon 
  most 
  oyster- 
  

   grounds, 
  the 
  oysters 
  are 
  scattered, 
  the 
  proportion 
  must 
  be 
  exceedingly 
  

   small. 
  Oystermen 
  are 
  well 
  acquainted 
  with 
  the 
  fact 
  that 
  upon 
  beds 
  

   removed 
  from 
  the 
  influence 
  of 
  the 
  tides 
  the 
  rate 
  of 
  reproduction 
  is 
  

   very 
  low. 
  

  

  Currents, 
  however, 
  will 
  bring 
  about 
  a 
  distribution 
  of 
  the 
  genital 
  

   products, 
  more 
  j)articularly 
  the 
  almost 
  impalpable 
  milt, 
  and 
  thus 
  give 
  

   an 
  opportunity 
  for 
  obtaining 
  better 
  results 
  by 
  increasing 
  the 
  chances 
  

   for 
  spawn 
  and 
  milt 
  to 
  come 
  into 
  contact. 
  Although 
  the 
  young 
  spat 
  is 
  

   a 
  free-swimming 
  organism, 
  yet 
  its 
  powers 
  are 
  not 
  sufficient 
  to 
  carry 
  it 
  

   to 
  any 
  great 
  distance 
  from 
  its 
  original 
  source. 
  It 
  is 
  transported 
  mainly 
  

   by 
  tidal 
  currents, 
  and, 
  as 
  a 
  general 
  rule, 
  the 
  more 
  widely 
  distributed 
  

   a 
  given 
  lot 
  of 
  spat, 
  the 
  greater 
  is 
  the 
  number 
  liable 
  to 
  become 
  success- 
  

  

  