268 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



It should also be noted that plaice are not of necessity 

 restricted to comparatively shallow waters. The opinion 

 of most fishermen and others is that outside the 20-fathom 

 contour line plaice are hardly to be found, and no doubt 

 this is largely true. But the fish does migrate, at least, 

 through waters of much greater depth than this, for we 

 have found that they may cross the Irish Channel, which 

 nowhere has a depth of less than about 50 fathoms, and 

 one plaice (L541, Experiment 14, 1905) was actually 

 caught by a steam trawler in water of 57 fathoms W.S.W. 

 from the Smalls Light. 



Evidence that the marking operation, if carried out 

 carefully on a vigorous plaice, has no effects which are 

 prejudicial to the normal movements and growth of the 

 fish is afforded by several plaice which have been 

 recaught after a considerable lapse of time. No. L104 

 was taken after exactly two years had elapsed since the 

 time of liberation : this fish had grown 7J inches. 

 No. L287, too, was recaptured after being almost exactly 

 two years in the sea : it had grown 6J inches ; and 

 No. L288 was also retaken after very nearly the same 

 interval, and was 6| inches larger than when marked. 

 All these fishes passed through my hands, and their 

 condition was that of normal well-nourished fishes, while 

 the wound caused by the affixed mark was clean and not 

 much larger than when initially made. Then quite a 

 number of fishes have been returned after having been in 

 the sea for periods of from 9 to 15 months, and with few 

 exceptions normal rates of growth were exhibited. 



