87 



and those with seven winter rings comprised 17 per cent, of the 

 1921 sample. The fifth year growth of these fish is given below : — 



NUMBERS AT CENTIMETRES. 



Sample. ^ lnter 26 27 28 29 



Rings. 



21/2/20 6 — — 3 22 



12/2/21 7 14 11 14 



Such a difference in growth is considered to point to the 

 spring spawning herrings of the north-west of the Shetlands being 

 different from the shoals which frequent the waters of the east 

 coast of the islands. 



The samples from Great Yarmouth, 9th March, 1921, is the 

 first we have examined from the shoals of spents which appear 

 off Yarmouth in the spring. Of the 171 herrings comprising the 

 sample, 168 were spents or recovering spents. In the November 

 sample, 1920, most of the fish were at stages III. and IV., 195 

 out of 225. The percentage of herrings with four winter rings, 

 the last winter ring being inside the edge of the scale, was 35 in 

 the November sample, and in the March sample 27 per cent, had 

 five winter rings, the last winter ring coinciding with the edge 

 of the scale. The growth of these fish is so similar that it is given 

 below, and it is considered it points to a return of herrings to 

 Yarmouth waters after spawning has taken plaec. 



FIRST YEAR GROWTH. 

 Number at Centimetres 



Sample. !T. * 7 8 9 10 11 12 13 14 15 Total. 



Rings 



17/11/20 4 1 17 28 8 10 5 1 2 1 79 



9/3/21 ... 5 — 1 11 15 9 2 1 — 1 46 



SECOND YEAR GROWTH 

 Number at Centimetres 



THIRD YEAR GROWTH. 



Number at Centimetres. 



