RAPPORTS. XIV : THOMPSON 



— 26 



decrease in the south-western areas, a greater and greater increase in the south-eastern; 

 in 1908 a large decrease over the greater portion of the North Sea, but a slight tendency 

 to increase (apparently) in the North; in 1909 a decrease more or less over all, greatest 

 in the south-east and tending to disappear in the north; in 1910 a marked increase in 



the southern part of the North Sea and a tendency to 

 diminution in the northern part, which becomes more 

 manifest the further north we go. 



f. Comparison of total Catch in 1903 — 1910 



(Table VII). 



Fig. 50. Total Demersal Cath of 



English North Sea Trawlers, 1903 — 



10, in percentage differences from the 



mean of the period. 



Fig. 51. Total Catch of Haddock of 



English North Sea Trawlers, 1903 — 



1 o, in percentage differences from the 



mean of the period. 



A brief comparison of the mean annual average catch 

 (per day) of the various fishes from year to year is of 

 some interest, although it cannot be taken without caution 

 as an index of actual changes in the abundance ot the 

 supply, owing to the differences in the different years with 

 respect to the grounds fished over. A full and detailed 

 discussion of the subject should therefore deal separately 

 with at least all the principal areas. However, I here give, 

 as in my former report, the mean annual catch of the 

 various fishes since the year 1903 (Table 7 a), expressed 

 in terms of the annual departure from the mean of the 

 whole eight years. It will be seen that of the seven 

 fishes dealt with in this report, the Cod and Whiting 

 are the only ones in which the series ends above the 

 mean line. 



The mean total demersal catch (fig. 50) fell steadily 

 from more than 20 °/o above the average in 1903, to some- 

 what below the average in 1905, it rose again for two 

 years, and has since fallen to a point about 15 °/o below 

 the mean. 



As usual, we find that the most abundant of all our 

 fishes, the Haddock (fig. 51), agrees in its fluctuations very 

 nearly with the fluctuations of the total catch, owing to 

 the simple fact that the total catch is dominated by this 

 predominant fish. We see accordingly that the curve for 

 Haddock repeats that for the total catch, but in a some- 

 what exaggerated form. The mean daily catch of Haddock 

 for 1905 was l5°/o below the average of the eight years; 

 it rose in 1907 to 16 °/o above the mean, and has since steadily fallen till it was very 

 nearly 30 /o below in 1910. This fish has been dealt with already in greater detail, and 

 we have shown in what parts of the North Sea the more marked deficiency from year 

 to year occurred. 



As we formerly found from the facts of earlier years, the fluctuations of Whiting (fig. 



Fig, 52. Total Catch of Whiting of 



English North Sea Trawlers, 1903 — 



10, in percentage differences from the 



mean of the period. 



