﻿46 
  OTTER-TRAWL 
  FISHERY. 
  

  

  that 
  on 
  the 
  326 
  trips 
  made 
  by 
  the 
  steam 
  trawlers 
  in 
  1913 
  the 
  boards 
  

   alone 
  scraped 
  about 
  115 
  square 
  miles 
  of 
  the 
  bottom, 
  provided 
  they 
  

   were 
  in 
  constant 
  contact. 
  

  

  The 
  footline 
  or 
  ground 
  rope 
  forms 
  the 
  front 
  border 
  of 
  that 
  part 
  

   of 
  the 
  net 
  lying 
  on 
  the 
  bottom. 
  It 
  stretches 
  in 
  a 
  curve 
  between 
  

   the 
  otter 
  boards, 
  is 
  about 
  140 
  feet 
  long, 
  and 
  3^ 
  to 
  4 
  inches 
  in 
  di- 
  

   ameter. 
  It 
  is 
  composed 
  of 
  a 
  core 
  of 
  steel 
  wire 
  rope 
  about 
  1 
  inch 
  

   in 
  diameter, 
  heavily 
  served 
  with 
  marlin 
  and 
  rope 
  partly 
  to 
  protect 
  

   the 
  wire 
  from 
  chafing, 
  but 
  principally 
  to 
  prevent 
  undue 
  cutting 
  into 
  

   the 
  bottom. 
  The 
  ground 
  rope 
  weighs 
  about 
  800 
  pounds 
  in 
  the 
  air, 
  

   but 
  as 
  rope 
  is 
  but 
  little 
  heavier 
  than 
  water 
  and 
  the 
  wire 
  weighs 
  

   not 
  over 
  150 
  or 
  160 
  pounds, 
  it 
  is 
  certain 
  that 
  when 
  at 
  rest 
  it 
  does 
  

   not 
  exeit 
  a 
  pressure 
  in 
  excess 
  of 
  2 
  pounds 
  per 
  linear 
  foot. 
  

  

  The 
  ground 
  rope 
  sweeps 
  over 
  a 
  strip 
  about 
  100 
  feet 
  wide, 
  and 
  

   using 
  the 
  same 
  data 
  employed 
  in 
  the 
  discussion 
  of 
  the 
  otter 
  boards 
  

   this 
  would 
  cover 
  an 
  area 
  of 
  about 
  73 
  acres 
  per 
  haul 
  and 
  about 
  

   1,300 
  square 
  miles 
  for 
  all 
  hauls 
  made 
  by 
  the 
  steam 
  trawlers 
  in 
  1913. 
  

  

  The 
  net 
  with 
  its 
  chafing 
  gear, 
  a 
  device 
  of 
  old 
  netting 
  to 
  minimize 
  

   abrasion 
  on 
  the 
  bottom, 
  weighs 
  about 
  800 
  pounds 
  in 
  air, 
  but 
  very 
  

   little 
  in 
  water. 
  As 
  fish 
  weigh 
  but 
  little 
  more 
  than 
  water, 
  the 
  catch 
  

   adds 
  nothing 
  to 
  the 
  pressure 
  of 
  the 
  net 
  on 
  the 
  bottom 
  unless 
  it 
  

   includes 
  stones, 
  sand, 
  shells, 
  and 
  other 
  heavy 
  materials. 
  The 
  net, 
  

   being 
  attached 
  to 
  and 
  following 
  the 
  ground 
  rope, 
  sweeps 
  over 
  the 
  

   same 
  area. 
  

  

  The 
  otter 
  boards, 
  by 
  virtue 
  of 
  their 
  inclined 
  position 
  to 
  the 
  line 
  

   of 
  draft 
  through 
  the 
  water, 
  act, 
  when 
  resting 
  on 
  the 
  bottom, 
  like 
  

   the 
  scraper 
  of 
  a 
  road 
  machine, 
  such 
  material 
  as 
  they 
  dislodge 
  or 
  

   tear 
  loose 
  passing 
  backward 
  and 
  inward 
  toward 
  the 
  net. 
  As 
  the 
  

   purpose 
  of 
  the 
  boards 
  is 
  to 
  spread 
  the 
  net 
  laterally, 
  no 
  useful 
  pur- 
  

   pose 
  is 
  served 
  by 
  permitting 
  them 
  to 
  plow 
  deeply, 
  and 
  the 
  ideal 
  

   practice 
  is 
  to 
  have 
  them 
  skim 
  over 
  the 
  bottom 
  as 
  lightly 
  as 
  possible. 
  

   The 
  drag 
  of 
  the 
  towing 
  warps, 
  inclining 
  upward 
  toward 
  the 
  vessel, 
  

   tends 
  to 
  lift 
  the 
  boards, 
  especially 
  at 
  the 
  forward 
  ends, 
  and 
  this 
  

   tendency 
  increases 
  with 
  the 
  speed 
  at 
  which 
  they 
  are 
  towed 
  and, 
  at 
  

   any 
  given 
  depth, 
  inversely 
  with 
  the 
  length 
  of 
  warp 
  paid 
  out. 
  With 
  

   the 
  speed 
  too 
  great 
  or 
  the 
  warp 
  too 
  short, 
  the 
  boards 
  and 
  with 
  them 
  

   the 
  net 
  may 
  be 
  lifted 
  quite 
  clear 
  of 
  the 
  bottom. 
  A 
  slight 
  lifting 
  

   of 
  the 
  boards 
  is 
  permissible 
  and 
  perhaps 
  desirable, 
  but 
  if 
  the 
  ground 
  

   rope 
  raises 
  materially, 
  the 
  efficiency 
  of 
  the 
  net 
  is 
  impaired. 
  

  

  There 
  are 
  two 
  instruments 
  employed 
  in 
  fisheries 
  in 
  other 
  parts 
  

   of 
  the 
  world 
  for 
  taking 
  bottom 
  growths, 
  the 
  efi^ects 
  of 
  which 
  are 
  

   comparatively 
  well 
  known, 
  and 
  a 
  consideration 
  of 
  these, 
  by 
  analogy, 
  

   may 
  be 
  of 
  some 
  assistance 
  in 
  the 
  formulation 
  of 
  an 
  opinion 
  as 
  to 
  

   the 
  effects 
  of 
  the 
  otter 
  trawl. 
  One 
  of 
  these 
  is 
  the 
  dredge 
  extensively 
  

   employed 
  in 
  the 
  oyster 
  fishery. 
  This 
  consists 
  of 
  a 
  short 
  chain 
  bag 
  

  

  