17 



abundance of yoang herrings, fish with three winter rings on their 

 scales. The grounds frequented by the shoals of herrings of this 

 class are invaded in the autumn by spawning shoals of older herrings. 

 The winter samples coming from shoals of herrings which are 

 spring spawners, are predominately old fish, the chief year classes 

 being fish with six and seven winter rings. These fish are of great 

 interest, for their presence is of importance in the sami)les from all 

 the grounds, Stornowa}^ Lerwick, north coast of Sutherland and 

 the Firth of Forth. They are fish which during the years of the 

 war have been protected to a large extent by less intensive fishing 

 than obtained in pre-war days. 



For all samples of winter herring caught in 1920 the last 

 winter ring has been considered to coincide with the edge of the 

 scale. Fish in these samples with five winter rings are assumed 

 to be similar, therefore, from the standpoint of age to those with 

 four winter rings caught in 1919. Herrings of this age become 

 poorly represented in the sample of 20th November from Yarmouth, 

 and their occurrence in comparatively small numbers is a general 

 feature of the samples of winter herrings. 



Stornoway Samples.— The first of the samples from 

 StornoAvay, caught 20 miles north of the Butt of Lewis, 27th May, 

 consisted of fish varying in age. Young fish with three winter 

 rings were fairly abundant, and amongst the older fish herrings 

 with five winter rings were not well represented. These fish were 

 practically all at stage II. of maturity. It will be shoA\ii later 

 that there is reason for supposing that this sample contained a 

 large number of recovered spents from a spring spawning shoal. 

 The samples of 22nd July and 23rd September were from the 

 summer shoals of young herring and the autumn spawning fish 

 respectively. The former shows the abundance of j^oung fish, 

 mostly virgins and developing herrings, present in the shoal, and 

 the latter illustrates the influx of older spawning herrings and the 

 presence amongst the spent fish of a number of young herrings 

 which had spawned probably for the first time. There was also 

 in the September sample a small number of young fish which had 

 not spawned, some virgin fish and others at stage II. which could 

 not have become autunni spawners in the year of capture. 



The winter samples both show how poorly the herrings with 

 five winter rings were rej)resented, but they differ much in age 



