60 liEPOKT OF THE COUNCIL. 



It will be seen that in spite of many trials, the sole has not proved a 

 very suitable subject for experiments of this kind, as the number 

 of recaptures has been excessively small compared with the labour 

 involved. On the other hand, the experiments with other flat-fish, 

 especially brill, turbot, and lemon sole, have been very satisfactory, 

 and merely require to be carried out on a large scale in order to yield 

 results of interest comparable with those of the plaice. 



The experiments with cod and thornback, though not so numerous 

 as is desirable, have yielded results of great value, both as regards the 

 migrations and rate of growth of these fishes ; and the two recaptures 

 of marked latchet have also shown features of considerable interest. 



Marked Coconuts and Drift Bottles. — With the object of obtain- 

 ing additional data on the relative intensity of trawling in different 

 parts of the North Sea, 859 perforated coconuts, to each of which 

 a numbered brass label was attached, were thrown overboard from 

 the Huxley in September last. They were put out at equal intervals of 

 one mile along lines which traversed the chief fishing grounds of the 

 Lowestoft smacks as well as the Dogger Bank and the grounds east 

 and west of it. Many of these nuts have been returned to the 

 Lowestoft Laboratory by fishermen and the Association's agents with 

 particulars of capture, but a complete year must elapse before it would 

 be profitable to compare the records. 



Of the bottles designed by Mr. Bidder for the study of bottom 

 currents, 170 were put out along three lines in the southern part of 

 the North Sea in November and December. Mr. Bidder has communi- 

 cated to the International Council an account of some results of 

 former experiments carried out on the Huxley with these bottles. 

 In these experiments the bottles were recovered by commercial 

 trawlers over all the area at the rate of 54 per cent per annum, while 

 in particular districts the rate of recovery was even higher. 



B. LABORATOKY WOEK. 



Age of Plaice. — A detailed report on the age of plaice based on the 

 examination of nearly 8,000 otoliths collected up to the end of 1905, 

 has been completed and is now in the press. 



The report, besides demonstrating the reliability of the methods 

 of age-determination employed, contains definite information in 



regard to 



1. The distribution of the various age-groups in the southern 



part of the North Sea. 



2. The relation of size to age on different fishing grounds. 



3. The rate of growth of young plaice on the English inshore 



grounds. 



