32 



It is scarcely necessary to draw attention to the fact that such 

 experiments are apt to be marred by many factors of variation. 

 The state of the tide {v. Northumberland Report for year ending 

 May, 1901) influences the inshore flat fish ; the season may be 

 relatively rich or poor, late or early. It has been thought desirable 

 therefore to choose from the " Garland " experiments a single 

 season's results in St. Andrews Bay practically chosen at random, 

 except that the year chosen (1889) seemed to present a fairly 

 representative series of hauls spread over the various seasons of 

 the year. The results of that year's experiments are indicated in 

 the upper part of fig. 3 (viewed as in the figure below from north to 

 south). From this diagram it is again plain that the main body 

 of plaice enter St. Andrews Bay from the north, and the return 

 migration brings them mto the northern part of the bay again. 



What has been said with reference to plaice apphes equally 

 to dabs, but as will be seen from Table I. and fig. 4 the migrants 

 enter the Northumberland and the other districts from the south 

 and relatively few reach the northern part of the several regions. 

 In the Hght of what has already been stated for plaice the diagrams 

 shown in fig. 4 require httle explanation. The upper two diagrams 

 refer to a single year's experiments of the " Garland " in the Firth 

 of Forth and in St. Andrews Bay, the third diagram is based on 

 the average figures of Table I. In the case of St. Andrews, it will 

 be seen that m 1889 the dabs were particularly prominent in the 

 two southern bays. That they pass outside that area is shown by 

 the fact that their disappearance from the mshore waters is asso- 

 ciated with their appearance in large numbers at Station 5, outside 

 the territorial waters in October and November. It may be noted 

 here also that the dabs of Station 5 at this season are mostly small 

 in size. 



The trawhng experiments therefore indicate with reference to 

 the two schools which have been considered (1) that plaice enter 

 these regions from the N.E. and return in the same direction, that 

 dabs enter the regions from the S.E. and return also in a S.E. 

 direction ; (2) that the migrations are periodic ; (3) that the 

 migration is a partial one. In both regions a larger number of 

 plaice and a smaller number of dabs pass the winter m the inshore 

 areas. Fig. 1 illustrates the relative conditions of the inshore and 

 offshore areas as the result of this periodic migration, and may serve 

 to picture the conditions generally around the coast, that is, with 



