126 



Age and the Migration Paths. 



Fig. 14 and the following table show how the migration 

 paths depend on the age of the plaice : — 



Marked Plaice liberated on the Ribble area and recaptured at the 

 various grounds mentioned in the headings. 



* Outside the Irish Sea. 



We see from the table that the smaller fish are those that 

 have been recaptured in the central area limited by the August 

 boundary line in Fig. 14, and those taken in the bays and 

 estuaries of the Lancashire coast during the few months 

 immediately following the date of liberation. In these fishes 

 the prevalent size (shortest half-range) is about 22 to 25 cms. 

 Those taken on the grounds off the N.E. Coast of Isle of Man 

 and in the Red Wharf Bay Estuary are a little bigger, 23 to 26 

 and 25 to 29 respectively. This means that there is a tendency 

 to segregation according to the stage of maturity. The latter 



