REPORT OF THE COUNCIL. 



59 



ANNUAL INCREMENT. 



15 cm. 

 10 cm. 

 13 cm. 



6 cm. 



7 cm. (nearly). 

 6 cm. (nearly). 



in 1904. On the other hand, experiments on the coastal banks and on 

 the Flamborough Off Grounds have shown that in the western part of 

 the North Sea the area of rapid growth is apparently limited to the 

 Dogger Bank, and does not extend to the grounds south or west of the 

 Dogger Bank. 



The following table summarizes the chief results obtained from these 

 experiments as to the average annual increase in length of small plaice, 

 the great majority of which ranged between 19 and 23 cm. in length at 

 the time of liberation. 



EXPERIMENT. 



Dogger Bank, 1904 . 



„ 1905 . 



„ 1906 . 

 Leman Banks, 1905 

 Flamborough Off' Ground, 1906 

 Well Bank, 1906 



Data yielded by the trawling experiments and fishermen's records, 

 as well as by the investigations made concerning the food of fishes, 

 render it highly probable that the above variations in the growth of 

 plaice on the Dogger Bank are mainly due to competition for the same 

 articles of food between this fish and the haddock. Young haddock 

 were much more abundant in 1905, when the growth of plaice was 

 relatively small, than in either of the years before or after. 



The transplantation experiments to the Dogger Bank have been 

 again repeated during the spring of the present year, and have been 

 extended to certain grounds on the Great and Little Fisher Banks. 



The experiments devised last year to test whether still smaller plaice 

 of a length of 2-4 inches would thrive if transplanted to the Dogger 

 Bank have been unsuccessful. 



Experiments with marked fish have also been carried out upon cer- 

 tain other species besides the plaice, as shown in the following table: — 



NO. RECAUGHT. 



23 

 7 

 7 

 6 



40 

 1 



26 



