228 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The Effect of the War Restrictions on the Fisheries. 



It will be seen, then, that the results of the Irish Sea 

 investigations give little evidence that the restrictions that 

 were in operation during the years 1915-18 had any very marked 

 effect. Now we must not assert this conclusion as holding 

 for any other fishing region than that studied here : There is 

 evidence that the war restrictions had an effect in the North 

 Sea — although this evidence is not entirely convincing. So 

 far as it goes, however, it suggests that during those years in 

 which the ordinary intensity of fishing (that characteristic of 

 the pre-war years) was in operation, there was a gradual 

 falling off of the quantities of plaice landed, as well as in the 

 average quantities caught per day's fishing. This decline 

 persisted throughout the years 1908 to about 1914. Then 

 followed about five years during which the existence of mine- 

 fields, and other conditions, greatly reduced the area over which 

 steam trawlers and smacks could fish. When it became possible 

 to resume trawling on a scale comparable with that of the pre- 

 war years it was seen that the quantities of plaice landed per 

 day's fishing had increased. At the same time measurements 

 made at sea aboard the fishing vessels showed that the plaice 

 were, on the average, markedly bigger than they were in, say, 

 the year 1913. The natural conclusion was that the reduced 

 fishing in 1914-1918 had allowed the plaice, that would 

 otherwise have been caught, the opportunity to live and grow. 

 In 1919, therefore, there was an " accumulated stock " on the 

 North Sea grounds, the results of a period of " protection." 



Now when the same argument is applied to the Irish Sea 

 grounds the same conclusion follows. There was evidence of 

 a decrease in the abundance of plaice during the pre-war 

 years and there was a marked restriction in the intensity of 

 fishing during the war years. In 1920 the size of plaice had 



