8 



North European Seas. It was previously known that herrings 

 from the North Sea, Baltic, Norwegian coasts, etc., presented 

 various peculiarities — mainly in the proportions of the parts 

 of the body — and it was thought that these variations in form 

 were good evidence in favour of the idea that each great sea 

 area had a different " race " of herrings, and that there was 

 little or no inter-mixture between these various races. The 

 migrations and shoaling movements made by the fish were, 

 it was thought, all local ones. It was assumed that by making 

 large series of measurements certain bodily characters could 

 be found which would serve to distinguish between these 

 various races. The first series of measurements were made 

 by Mr. W. Riddell in 1913 and 1914, and the research was then 

 suspended until 1919, when it was resumed by Mr. W. Birtwistle 

 and Miss H. M. Lewis. 



It was suspected that even in such a small area as the 

 Irish Sea there would be more than one race of herrings. It 

 is known, of course, that there are at least two such races : 

 one which shoals off the S.W., S. and S.E. Coast of Isle of Man 

 sometime about May or June, and then spawns in August or 

 September, when the shoals disperse. Another school of 

 herrings shoals in Cardigan Bay sometime about October and 

 November, and then proceeds to spawn. In this case the 

 shoaling and spawning begin first at the southern extremity 

 of Cardigan Bay and then takes place a little later in the year 

 in Carnarvon Bay, and finally off the North Coast of Anglesey. 

 This is the usual progress of the fishing, and what we know 

 about it is derived from the catches made by the local boats, 

 for we have never been able to make big fishing experiments 

 ourselves. The herrings may, however, appear much earlier 

 in the spring, off the Manx coasts, than May, when the com- 

 mercial fishery usually begins, and it is quite possible that they 

 are there from the beginning of the year, but their quality is 

 so poor that it is not worth whi-le catching them. 



