﻿44 
  OTTER-TRAWL 
  FISHERY. 
  

  

  trawlers. 
  Both 
  methods 
  of 
  jBshing 
  catch 
  a 
  few 
  halibut 
  and 
  certain 
  

   edible 
  fishes 
  which 
  are 
  not 
  marketed. 
  The 
  haddock 
  and 
  the 
  cod 
  are 
  

   the 
  principal 
  species 
  sought, 
  and 
  were 
  it 
  not 
  for 
  these 
  the 
  bank 
  

   fisheries 
  would 
  not 
  exist 
  under 
  present 
  economic 
  conditions. 
  

  

  Both 
  of 
  these 
  fish 
  are 
  bottom 
  feeders, 
  and 
  while 
  they 
  feed 
  to 
  some 
  

   extent 
  on 
  young 
  or 
  small 
  fishes, 
  their 
  diet 
  consists 
  principally 
  of 
  in- 
  

   vertebrates 
  such 
  as 
  constitute 
  the 
  bottom 
  fauna 
  of 
  the 
  banks. 
  They 
  

   all 
  sometimes 
  contain 
  pieces 
  of 
  herring 
  and 
  similar 
  fishes, 
  but 
  there 
  is 
  

   good 
  reason 
  to 
  believe 
  that 
  in 
  most 
  cases 
  these 
  are 
  baits 
  taken 
  from 
  

   the 
  lines. 
  Most 
  of 
  the 
  food 
  consists 
  of 
  echinoderms 
  (starfishes, 
  brittle 
  

   stars, 
  sea 
  urchins, 
  and 
  sea 
  cucumbers; 
  lamellibranchs 
  (scallops, 
  

   mussels, 
  and 
  other 
  bivalves) 
  ; 
  gasteropods 
  (various 
  snail-like 
  mol- 
  

   lusks) 
  ; 
  crustaceans 
  (crabs 
  and 
  shrimps); 
  and 
  annelids 
  (worms). 
  

   Although 
  these 
  fishes 
  spawn 
  on 
  some 
  of 
  the 
  banks, 
  they 
  resort 
  to 
  

   them 
  primarily 
  for 
  food; 
  and 
  there 
  is 
  no 
  doubt 
  that 
  if 
  the 
  bottom 
  

   growth 
  were 
  destroyed 
  the 
  productiveness 
  of 
  the 
  fishing 
  banks 
  would 
  

   be 
  seriously 
  impaired 
  if 
  not 
  destroyed, 
  and 
  it 
  is 
  therefore 
  important 
  

   to 
  the 
  present 
  inquiry 
  that 
  the 
  methods 
  of 
  fishing 
  now 
  pursued 
  

   should 
  be 
  considered 
  in 
  relation 
  to 
  their 
  effects 
  on 
  the 
  denudation 
  

   of 
  the 
  bottom. 
  

  

  In 
  this 
  respect 
  the 
  trawl-line 
  fishery 
  is 
  innocuous 
  and 
  need 
  not 
  be 
  

   discussed, 
  but 
  the 
  otter 
  trawl 
  operates 
  in 
  such 
  manner 
  as 
  to 
  raise 
  a 
  

   valid 
  assumption 
  against 
  it 
  and 
  to 
  demand 
  a 
  critical 
  examination 
  of 
  

   its 
  effects. 
  As 
  the 
  otter 
  trawl, 
  as 
  a 
  whole, 
  sweeps 
  over 
  an 
  area 
  of 
  

   about 
  80 
  acres 
  at 
  each 
  haul 
  and 
  many 
  square 
  miles 
  in 
  the 
  course 
  of 
  a 
  

   year's 
  fishing, 
  the 
  assumption 
  has 
  been 
  that 
  its 
  effects 
  on 
  the 
  bottom 
  

   growths 
  of 
  necessity 
  must 
  be 
  disastrous; 
  and 
  the 
  observers 
  on 
  the 
  

   steamers 
  were 
  instructed 
  particularly 
  to 
  note 
  the 
  quantity 
  and 
  char- 
  

   acter 
  of 
  the 
  bottom 
  materials 
  brought 
  up. 
  Most 
  of 
  the 
  sand, 
  broken 
  

   shells, 
  and 
  other 
  fine 
  material 
  not 
  bound 
  together 
  by 
  worm 
  tubes, 
  etc., 
  

   undoubtedly 
  would 
  wash 
  through 
  the 
  mesh 
  and 
  would 
  not 
  figure 
  in 
  

   the 
  load 
  landed 
  on 
  deck, 
  but 
  a 
  large 
  part 
  of 
  the 
  bottom 
  growth, 
  

   which, 
  and 
  not 
  the 
  bottom 
  itself, 
  is 
  the 
  important 
  factor 
  in 
  the 
  pres- 
  

   ent 
  inquiry, 
  would 
  come 
  up 
  in 
  the' 
  trawl. 
  

  

  Much 
  of 
  the 
  data 
  submitted 
  by 
  the 
  observers 
  are 
  too 
  vague 
  for 
  

   quantitative 
  consideration, 
  but 
  one 
  man 
  definitely 
  states 
  the 
  quan- 
  

   tities 
  in 
  bushels 
  in 
  his 
  monthly 
  analysis 
  of 
  the 
  results 
  of 
  his 
  obser- 
  

   vations 
  on 
  each 
  bank. 
  From 
  his 
  returns 
  it 
  is 
  deduced 
  that 
  the 
  aver- 
  

   age 
  quantity 
  of 
  scallops, 
  clams, 
  shells, 
  sponges, 
  starfishes, 
  and 
  bottom 
  

   material 
  generally, 
  varied 
  with 
  the 
  month 
  and 
  the 
  locality, 
  from 
  a 
  

   small 
  fraction 
  of 
  a 
  bushel 
  to 
  4.7 
  bushels 
  per 
  haul, 
  the 
  latter 
  being 
  

   the 
  average 
  of 
  26 
  hauls 
  made 
  in 
  South 
  Channel 
  in 
  August, 
  1913. 
  

  

  A 
  simple 
  computation 
  shows 
  that 
  this 
  maximum 
  represents 
  a 
  film 
  

   0.00024 
  inch 
  in 
  thickness 
  spread 
  over 
  the 
  area 
  swept 
  by 
  the 
  trawl, 
  or. 
  

   to 
  state 
  the 
  case 
  in 
  another 
  way, 
  a 
  little 
  pile 
  of 
  material 
  1 
  foot 
  

  

  