148 



views: (1) that the marking stimulates the tish to travel 

 further than it would otherwise have done ; and (2) that 

 the marking makes them sluggish. I do not think that 

 either of these views is correct ; they are, indeed, only the 

 usual kind of conjectures made by fishermen Avith regard 

 to matters outside their experience. Nearly everything 

 we have seen of the behaviour of marked plaice indicates 

 that they behave normally. Marked plaice have never 

 been caught by themselves. Where they have been 

 caught in unusual numbers there have also been large 

 catches of unmarked plaice made. In the case of 

 Experiment XI Y., for instance, an unusually large 

 number of marked plaice M'ere returned, and all, with one 

 exception, from the localitj^ where they were originally 

 caught. But during all this time plaice were very abun- 

 dant here and large catches were made by the fishing 

 boats. The marked plaice, in fact, behaved just as the 

 otjier fishes on this ground did. 



Again, it is not uncommon to catch perfectly healthy 

 plaice and other flat fishes which have suffered mutilation. 

 I may also instance the case of a marked plaice re-caught 

 a few weeks ago in Luce Bay, after 15 months from the 

 date of liberation. This fish was in excellent condition, 

 and the wound made by the mark had not become greater 

 than at first. The fish had grown 3|^ inches. 



In the meantime one may summarise the results as 

 follows : — 



1. The number of fish returned depends on the 

 intensity of fishing in the area into which the fish have 

 migrated, and gives a measure of th« latter. Thus of the 

 fish liberated on the Lancashire Stations, where fishing 

 is actively carried on, from 25 to 50 per cent, have been 

 returned within the year following liberation ; while on 

 the Welsh Stations, where there is very little fishing, the 



