320 REPOirr of the coqncil. 



Dogger Bank, in order to determine the direction of drift during the 

 spawning season of the sole and turbot. 



The HiLiIcy has recently completed a special survey of the spawning 

 grounds of the sole in the western part of the North Sea, and an 

 investigation of the distribution and abundance of the eggs of this 

 species in the same area, in co-operation with simultaneous surveys by 

 the Poseidon and Wodan in the German and Dutch areas respectively. 



P.. LABOKATOEY INVESTIGATIONS. 



Age of Fishes. — Considerable attention has been paid in the 

 Laboratory at Lowestoft to the investigation of the age and rate of 

 growth of fishes, especially the plaice, both by Petersen's statistical 

 method based on the periodicity of the spawning season, by Peibisch's 

 method based on the periodicity of growth of the otoliths, and by 

 direct observation of the increase in length of marked fishes. The 



'&^ 



result of these investigations is to show that the age of individual 

 plaice can now be determined with considerable exactitude — a matter 

 of much importance for the scientific treatment of fishery problems. 



Food of Fishes. — Extensive material has been collected and worked 

 up for determining the physical and biological characteristics of the 

 various grounds, and the food-contents of many thousands of fish- 

 stomachs have been studied and recorded. 



C. FISHEPMEN'S PECOPDS. 



1903-1904. — The system of fishermen's trawling records has recently 

 been extended to Grimsby, at which port several specially reliable 

 trawling skippers have been selected to take part in the work. The 

 Lowestoft records are being continued. These records deal with in- 

 dividual hauls of the trawl, and have been found useful for supplement- 

 ing and checking the results of the HiLxley's investigations, and in 

 providing a kind of outside " intelligence department " for keeping the 

 scientific staff informed of the most profitable regions for investigation 

 from time to time. 



1881-1882. — Log-books of a somewhat similar cliaracter, initiated 

 by Mr. Olsen, of Grimsby, with the co-operation of the late Mr. Frank 

 Buckland, were kept by a number of east coast fishermen in 1881 and 

 1882, and have been kindly entrusted to the Association by Mr. Olsen 

 for analysis and report. 



1892-1893. — Records more closely approximating to those now 

 being kept were again filled up for Mr. Holt, when in the service of 

 the Association, by various Grimsby fishermen in 1892 and 1893. 



The Association is thus in the possession of a unique series of 



