﻿OTTER-TRAWL 
  FISHERY. 
  

  

  65 
  

  

  AvEBAGE 
  Catch 
  of 
  Steam 
  Tkawleks 
  Fishing 
  in 
  the 
  North 
  Sea 
  from 
  the 
  

   East 
  Coast 
  of 
  England 
  Per 
  Day 
  of 
  Absence 
  During 
  the 
  First 
  and 
  Iiast 
  

   Years 
  of 
  Certain 
  Periods. 
  

  

  Species 
  and 
  periods. 
  

  

  Catch 
  (hundredweight) 
  

   during— 
  

  

  First 
  year. 
  Last 
  year. 
  

  

  Gain 
  or 
  loss. 
  

  

  Hundred- 
  

   weight. 
  

  

  Per 
  cent. 
  

  

  Demersal 
  fishes 
  

  

  1903-1906... 
  

  

  1906-1912... 
  

   Cod: 
  

  

  1903-1906... 
  

  

  1906-1912... 
  

   Haddock: 
  

  

  1903-1906. 
  . 
  . 
  

  

  1906-1912... 
  

   Plaice: 
  

  

  1903-1906... 
  

  

  1906-1912... 
  

  

  18.64 
  

   17.63 
  

  

  3.1 
  

  

  3.5 
  

  

  8.3 
  

   7.8 
  

  

  3.1 
  

   3.1 
  

  

  17.63 
  

   15.76 
  

  

  3.5 
  

   4.45 
  

  

  7.8 
  

   4.8 
  

  

  2.1 
  

  

  2.34 
  

  

  -1.0 
  

   -1.9 
  

  

  +0.4 
  

   +0.9 
  

  

  -0.5 
  

   -3.0 
  

  

  -1.0 
  

   +0.2 
  

  

  - 
  5 
  

   -10 
  

  

  +12 
  

   +27 
  

  

  -38 
  

  

  -30 
  

   +11 
  

  

  Average 
  Catch 
  Per 
  Voyage 
  of 
  Steam 
  Trawlers 
  Fishing 
  in 
  the 
  North 
  Sea 
  

   FROM 
  the 
  East 
  Coast 
  of 
  England 
  During 
  the 
  First 
  and 
  Last 
  Years 
  of 
  

   Certain 
  Periods. 
  

  

  These 
  two 
  tables 
  show 
  the 
  same 
  facts, 
  namely, 
  that 
  on 
  whichever 
  

   basis 
  computed, 
  the 
  average 
  catch 
  of 
  demersal 
  fishes 
  by 
  steam 
  trawl- 
  

   ers 
  has 
  decreased 
  from 
  1903 
  to 
  1912, 
  the 
  average 
  catch 
  of 
  cod 
  has 
  

   materially 
  increased, 
  while 
  the 
  yields 
  of 
  haddock 
  and 
  plaice 
  per 
  

   unit 
  of 
  effort 
  have 
  decreased, 
  the 
  former 
  over 
  63 
  per 
  cent 
  and 
  

   the 
  latter 
  over 
  37 
  per 
  cent. 
  

  

  A 
  frequent 
  manifestation 
  of 
  the 
  results 
  of 
  overfishing 
  is 
  the 
  per- 
  

   manent 
  relative 
  increase 
  in 
  the 
  catch 
  of 
  small 
  fishes, 
  particularly 
  

   if 
  the 
  absolute 
  quantity 
  of 
  the 
  catch 
  of 
  large 
  fishes 
  or 
  of 
  the 
  species 
  

   as 
  a 
  whole 
  remains 
  stationary 
  or 
  diminishes. 
  

  

  As 
  a 
  fishery 
  increases, 
  the 
  total 
  quantities 
  of 
  the 
  catch 
  will 
  also 
  

   increase, 
  while 
  the 
  ratios 
  existing 
  between 
  the 
  catch 
  of 
  the 
  various 
  

   sizes 
  will 
  be 
  maintained 
  provided 
  that 
  the 
  size 
  and 
  composition 
  of 
  

   the 
  fish 
  schools 
  remain 
  unimpaired. 
  When 
  overfishing 
  occurs, 
  how- 
  

   ever, 
  there 
  is 
  a 
  tendency 
  to 
  change 
  the 
  composition 
  of 
  the 
  schools 
  

  

  