EEPOET OF THE COUNCIL. 331 



ever, worthy of notice. It seems to be due to the small number of trans- 

 planted fish recovered, the returns from the Fisher Bank being particu- 

 larly small. Nearly two-thirds of all the fish marked were taken to 

 the Dogger Bank, Great Fisher Bank and Little Fisher Bank : the per- 

 centages of these recovered before June 1st, 1907, were 15*1 %, lO'l % 

 and 2'5 % respectively, while of the fish marked in the ordinary 

 marking experiments 34'6 % were caught again. 



The conditions under which they were captured being in some 

 respects unfavourable, there is reason to think that the transplanted 

 fish were not very strong ; this, together with the difterences of 

 intensity of fishing in the areas covered by the work of the two years, 

 probably accounts for the different rates of recapture; Of the 749 fish 

 transplanted in April and May, 1907, to the Dogger Bank, 15 were 

 recovered after an interval of 12 months, and show an average yearly 

 growth of 11*1 cm. Four fish were recovered a year after liberation 

 on the Great Fisher Bank, having increased in length by 5"0-10"7 cm. 

 Only one fish of those set free on the Little Fisher Bank was re- 

 captured after the same period ; this had grown 4"6 cm. 



During the year, 9 turbot, 3 cod and 3 latchets were also marked, 

 and the following marked fish were returned : 33 thornback rays, 

 17 soles, 10 cod and 3 brill. Considering the small number of fish 

 marked, and the fact that practically all were marked before June, 

 1907, the proportions of cod and thornbacks returned in the current 

 year seem to indicate that the mark is fairly suitable for work with 

 these fish. Of 295 soles marked in the year 1906-7 about 6 % 

 were recaptured before June 1st, 1908. 



Vitality Experiments. — The plaice caught in 14 hauls of the com- 

 mercial trawl were examined with a view to the estimation of the pro- 

 portion that would survive under various conditions of trawling, if 

 returned to the sea either at once or after certain periods on deck. The 

 number of plaice dealt with in these experiments is 16,163, each of 

 which had to be examined separately. 



Marked Coconuts. — In September, 1906, 859 coconuts were put 

 overboard in the North Sea. 142 of these nuts have now been 

 recovered. In many cases the wire by which the label is fastened to 

 the nut is found to be much worn, indicating a considerable amount of 

 motion at the sea bottom on which the nut rested. 



B. LABOEATORY WORK. 



Maturity of Plaice. — During the past year the investigations with 

 regard to the age and size of plaice at maturity in different parts of the 

 Nortli Sea and English Channel, and also those on the distribution of 



