27 



LATER STAGES OF GADOIDS 



Fig. 53. Total Catch of Cod of Eng- 

 lish North Sea Trawlers, 1903 — 10, 

 in percentage differences from the 

 mean of the period. 



Fig. 54. Total Catch of Ling of 



English North Sea Trawlers, 1903 — 



10, in percentage differences from the 



mean of the period. 



52) are in marked and direct contrast to those of Haddock. The average catch of Whiting 

 rose from below the mean in 1903 to 15 °/o above it in 1905, it fell gradually to over 

 20°/o below the mean in 1907, and it has since risen to a point about 20°/o above the 

 mean. 



In the case of Cod (fig. 53), the figure for 1903 was a trifle above the mean and 

 afterwards for five years stood more or less below the mean; in the years 1909 and 1910 

 it was about 20 °/o above. 

 In the case of Ling (flg. 54), 

 while the range of fluctuation 

 is not very wide, it is note- 

 worthy that all the first 

 five years stood above, and 

 all the last five years lay 

 below, the average for the 

 entire period. Saith, or Coal- 

 fish (fig. 55) has likewise 

 fluctuated comparatively 

 little, but the mean daily 

 catch for 1909, 1910, has 

 been in both cases well be- 

 low the average. The most 

 marked fluctuations, and the 

 most considerable decreases 

 have taken place in the case 

 of Hake and Tusk. The 

 best year for Hake (fig. 56) 

 was 1904, in which the daily 

 catch was 8o°/o above the 

 mean for the eight years; 

 it has since fallen with al- 

 most complete regularity, till 



it has reached during 1909 and 1910 a point very nearly 

 6o°/o below the mean; in other words the catch in recent 

 years has been only about a quarter of that in 1903—04. 

 In this case, if we consider the typical migratory habit 

 of the fish and its great and continued abundance upon 

 the western coasts, we cannot doubt but that we are 

 dealing with fluctuations due to some natural phenomenon, 

 and not caused by depletion on the part of man. 



That characteristically northern fish the Tusk (fig. 54) 

 also shows a descending curve. The catch in 1903 was 

 nearly double that of the mean catch for the entire period. 

 It fell by 1907 to about half of the mean catch, and 

 there has since then been a partial and slight recovery. 



Fig. 55. Total Catch of Saithe or 

 Coalfish of English North Sea Traw- 

 lers, 1903 — 10, in percentage diffe- 

 rences from the mean of the period. 



Fig. 56. Total Catch of Hake of 



English North Sea Trawlers, 1903 — 



10, in percentage differences from the 



mean of the period. 



180 

 160 

 140 



Fig. 57. Total Catch of Tusk of 



English North Sea Trawlers, 1903 — 



10, in percentage differences from the 



mean of the period. 



