APPENDIX H: GARSTANG _ ig — 



The results of the trawling experiments carried out by the internatianal steamers have 

 been analysed up to June 30"^ 1904, and charts are appended to the present report which 

 show the preliminary results of these investigations ^ 



The methods by which these charts have been drawn up are as follows. In the first place 

 the position of all the individual hauls was indicated upon special large-scale charts for each 

 successive season of three months^. By the side of these positions the average size of the 

 plaice caught, the catch of plaice above and below 30 cm. length for one hour's fishing, and 

 the percentage of plaice below 20 cm. length was indicated'^. A study of the individual data 

 thus charted showed that on the offshore grounds the conditions and results were very uniform 

 over extensive areas. In most of the countries concerned fixed stations for the trawling ex- 

 periments were not adopted at the commencement of the investigations, but a large number of 

 the Scottish experiments have been carried out at fixed stations month by month. A comparison 

 between the results of the Scottish investigations from April to June in 1903 and 1904, as 

 carried out in the Moray Firth, revealed a very striking uniformity at most of the stations 

 during the corresponding periods of the two years. In order, therefore, to compensate for the 

 small number of steamers specially engaged in scientific work, it was found possible to dis- 

 regard the yearly differences in the preparation of the charts, the main object of which is to 

 show the normal or average characters of the different fishing grounds irrespective of yearly 

 fluctuations. The great number of experiments carried out by the research steamers renders 

 it impossible, however, to show the results attained at each haul of the trawl in a graphic 

 manner upon small charts suitable for publication. The international area has, therefore, been 

 divided into a large number of small areas, (see the chart PI. Ill), the average characters of 

 which it appears to be possible to determine by means of the scientific experiments within the 

 five-year period specified in the Christiania programme. In sub-dividing the North Sea in this 

 way, attention has been paid to the depth of the bottom, the distance from shore, and the 

 character of the ground. Wherever possible also an attempt has been made to make the 

 boundaries of the lines coincident with boundaries known to be observed by the commercial 

 fishing vessels. Henking's ^ chart of the German trawling grounds and Olsen's Fishermen's 

 Chart of the North Sea have both been considered in this connection. And although I am well 

 aware that any attempt to sub-divide the North Sea at the present time into statistical areas 

 must be of a purely provisional character, I trust that the scheme adopted in the charts appended 

 to the present report will be found acceptable as a working basis. 



' The eight large charts appended to the M. S. of the present report could not be reproduced in redu- 

 ced size. As the report has a preliminary character and as it was desirable to publish it as soon as pos- 

 sible, it was thought better to omit these charts and to replace them by. 



a. a chart of the North Sea with the 100 grounds into which tlie author lias divided the North Sea (PI. HI); 



b. a table (Table V, p. 28) summarising the localities where the hauls with the trawl were made over the 

 100 grounds in the different seasons; and 



e. a table (Table VI, p. 32) summarising for each ground, in the different seasons, the number and the 

 average size of the plaice caught, the catch per hour and the percentage of those smaller than 20 cm. 



The General Secretary P.P. G. Hoe k 

 = See Table V, p. 28. 

 ' See Table VII, p. 34. 



* Henking, Die Befischuug der Nordsee durch deutsche Fisohdampfer. Mitteil. d. deutsehen Seefischerei- 

 Vereins. 1901. 



