SCIENTIFIC TRAWLING 185 



to be a period of intense spawning. Great catches of 

 eggs were made with the Petersen young-fish trawl and 

 Todds trawl, and almost every stage of development 

 was represented. 



Another interesting feature of the work conducted 

 by the Association is reported for February 1910. In 

 co-operation with Mr. G. P. Bidder drift bottles were 

 put out along a line stretching east-north-east from 

 Spurn. One hundred bottom drifters and 266 surface 

 drifters were put overboard, the first at 5 miles and 

 the last at 88 miles from land. This experiment took 

 place in an area which was previously untouched in 

 similar investigations, but was known to be a plaice 

 spawning-ground, and results of great interest were 

 yielded. Messrs. Wilson, of Hull, gave all facilities for 

 the work, and Captain French, of the s.s. Zero, con- 

 tributed valuable help during the voyage in which the 

 bottles were put out. A curious circumstance was noted 

 that the proportions of bottom-drift bottles returned 

 from fishing-vessels approximated to the percentages of 

 recoveries which were met with during a year amongst 

 the selected bright-eyed plaice to which reference has 

 been made. 



Grimsby trawlers assisted in the Association's work, 

 and a report of the fishermen's records gives a detailed 

 analysis of 13,246 hauls made by the skippers of these 

 vessels during the period 1904-7. These hauls were 

 allotted to twenty-three different areas in the central and 

 southern parts of the North Sea. Examinations were 

 made of the catches of seven species of food fishes 

 plaice, soles, turbot, brill, cod, haddock, and whiting, and 

 as far as possible the seasonal and yearly fluctuations of 



