sea-fisheries laboratory. 265 



General Conclusions. 



1. — P ercentage of fish, recovered. 



This, as the Summary Table shews, varies from 

 50 per cent, to 4 per cent, in the case of plaice, taking 

 each, experiment by itself. The causes of the difference 

 in the percentage of fishes recorded are (1) the intensity 

 of fishing, as for example in the case of Experiment 10, 

 where an active fishery was carried on during the summer 

 months over the area immediately contiguous to the place 

 of liberation ; (2) on the method of dispersal of the 

 marked fishes, as for instance in Experiments 11 and 16, 

 where the marked fishes liberated have probably been 

 widely dispersed into areas where little trawl fishing is 

 carried on ; and (3) on the vitality of the marked fishes, 

 as for instance in Experiment 5, where (as in the case of 

 Experiment 12 of 1905) plaice were marked which had 

 been for many months kept in tanks, and were in poor 

 condition. 



2. — I nfluence of methods of fishing'. 



Eirst-class sailing trawlers have recaught more 

 marked plaice than any other class of vessel or fishing 

 method. There is little doubt that in the Lancashire and 

 North Welsh Eishing Grounds this method of trawling 

 predominates, at least for the "home waters.' 1 The 

 steam trawlers have caught fewer fishes, but it is well 

 known that these vessels go much further afield and do 

 not frequent the grounds where the marked fishes may be 

 expected to be recaught to the same extent that the 

 smacks do. 



3. — R ate of growth. 



The estimates of the rate of growth of marked fishes 

 constructed on the results of the experiments of 1906 agree 



