35 



the same month they have suffered regression, recovering agam in 

 the succeedmg months. In this respect Cambois is exceptional, 

 and it is probable therefore that it like Blyth comes under the 

 influence of the next school, that in other words, over-lapping occurs. 

 The wave of plaice appears like that of the dab to consist of an 

 inshore larger body of small and an offshore smaller body of large. 



Dab. — The small number of winter dabs in the inshore waters 

 consists for the most part of those about 25 to 35 cms. The table 

 and the chart indicate very distinctly that the wave of dabs which 

 enter the region is made up of an advance and inshore assemblage 

 of small dabs followed by larger sizes which also enter the region 

 further north. It will be noted also that the small and the larger 

 dabs arrive m numbers which come to maxima in successive months 

 at the different stations from south to north. It is also plain that 

 while all sizes take part in the summer migration the large majority 

 are small and immature. 



A similar analysis has been prepared of the " Garland " results 

 in St. Andrews Bay and the Firth of Forth, but there is no need to 

 present further evidence to illustrate the main facts of this summer 

 inshore migration. The winter plaice in St. Andrews Bay appear 

 to be as the summary table on page 33 indicated mamly 30 to 40 cms. 

 In the Firth of Forth a larger body of plaice winter than in the more 

 exposed regions of St. Andrews and Northumberland. 



It may be concluded from this approach from the statistical 

 point of view that : — 



Plaice. — (1) There is a periodic migration of schools between 

 correlated offshore winter grounds and inshore summer grounds 

 The migration is subject to seasonal variation as to time and inten- 

 sity. 



(2) The majority of the plaice taking part in the movement arj 

 young and immature. This is illustrated also by the presentation 

 of sizes by Prof. D'Arcy W. Thompson * with regard to the Forth 

 school. 



(3) In the inshore waters of the regions which have been 

 particularly examined there is a predommance of plaice as stated 

 in the " law " at the northern part of the region and of the sub- 

 divisions thereof. The presumption therefore is that the migration 



* Loc. cit. 



