42 



THE STOCK OF PLAICE 



deciding whether or not to bring his ' small ' plaice to shore 

 a skipper will always be guided by two considerations : (1) Is 

 there a fair chance of filling up with bigger fish ? (2) Is there 

 a demand ashore for fish of that size ? If a big demand for 

 smaller sizes of plaice has grown up since 1906 the statistics 

 may mean little more than that plaice which were once thrown 

 away are now eaten, particularly in the fried-fish shops. 



■Brede Bugt 



Faxe Buqt 



Fae roe 

 BanU: 



F^eroe 1^ 



Shetland |s 



Orkney I ^rj'f* 



Fig. 3. — Marking Exiieriments from Iceland showing that in the spring 

 the mature plaice wander from colder waters (Vopnatiord and 8kjalfandi 

 Bay) to the southern and western shores in order to find suitable spawning 

 conditions. (Dr. Hjort after Dr. Schmidt.) The plaice in the North 8ea do 

 not appear to migrate, to such an extent as in Icelandic waters. 



Marking Ex'periments 



Many experiments have been made with marked plaice in 

 order to discover what percentage of the plaice population is 

 caught in the trawls every year. A certain number of fish, 

 say one hundred or one thousand, are marked with labels and 

 hberated on a particular ground. In the year after they are 

 cast adrift a certain number of these marked plaice (say 10 to 

 40 per cent.) will be recaptured in a certain area. If it is 

 assumed that the marked fish have distributed themselves 

 uniformly amongst the unmarked fish, the inference is drawn 

 (and is perhaps to some extent legitimate) that approximately 



