31 



young plaice are found numerously only in the northern part of 

 the district, and small dabs in the southern. 



Seasonal Changes. — We have so far considered the results 

 of the experiments made during the period June to September, 

 and even so it has already been apparent that we are not dealing 

 with a static population confined to territorial waters, the pro- 

 tection of which would be bound to lead to improvement. But 

 this becomes abundantly plain when the same stations are trawled 

 over in the colder part of the year. During the summer the in- 

 shore waters are rich in plaice and dabs, and receive also other 

 flat fish, but in winter they undergo a conspicuous relapse in all 

 kinds of flat fish. A number of experiments have been made 

 to demonstrate this, and when the results are brought into relation 

 with the summer experiments the general trend of the population 

 during the year is found to follow closely the changes in the 

 temperature of the water (figure 4). 



SEASONAL VARIATION, 1899-1913 

 1.— PLAICE. 

 Jan. Feb. Mar. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 



10 



31 



57 



31 — 



DAB. 



26 



48 78 



38 



The seasonal changes will gain in clearness by an inspection 

 of the following table, Table X., which gives with reference to 

 size the results of successive visits to the various bays. 



We have now the evidence before us to demonstrate certain 

 important points relating to the plaice and dabs of the shallow 

 waters close to the shore on the Northumberland coast, and the 

 evidence could be made still more impressive by a fuller state- 

 ment of the results. 



