37 



Tlie August samples, A2, 4, 10, came from practically the 

 same locality on the 2ncl, 6th and 22nd respectively. They 

 indicate in the case of the herrings with three winter rings the 

 joining of the shoal in August of fish with a comparatively large 

 first year growth, and towards the end of August the coming of 

 fish with a smaller first year growth. 



The first year growth for herrings with three winter rings was 

 as follows : — 



Percentage at Centimetres. 



Sample. 4 .3 G 7 8 9 10 11 12 13 14 :No3. 



A:' — — 2 12 2.3 28 22 8 2 — — 126 



4 _ _ _ 1 18 33 30 14 5 — — 101 



10 — — 2 15 31 35 14 3 — — — 104 



Herrings with four winter rings were not the predominant 

 year class in 1918, and sample A2 contained fifteen fish only of this 

 age. Th3 other two August samples show the same difference for 

 fish with four winter rings as they do for those a year younger. 

 The first year growth was as follows : — 



Percentage at centimetres. 



Sample. 4 5 6 7 8 9 10 11 12 13 14 Nos. 



A4 _ _ _ 6 39 34 20 1 — — — 70 



10 — — 2 26 31 27 12 1 — — — 81 



From the foregoing consideration of the first j'ear growth 

 made by the herrings of the Northumberland Coast shoal it would 

 appear that there are continued additions to the shoal throughout 

 the season. The herrings appear off the coast in May coming 

 from deeper water, being in April 100 miles from the coast (sample 

 1, 1914). During June and July there are additions to the shoal 

 of fish which have made a comparatively small first year gro^wth, 

 and these are followed in August by fish with a larger first year 

 growth, which in sample 10, 1914, showed a decreased growth 

 for the year of capture. In September, there is a further addition 

 to the shoal of fish with a comparatively small first year growth. 



It is assumed that these changes are brought about by 

 immigration into the shoal and not by emigration from it. Whilst 

 emigration may take place there is no evidence of it, and it is 

 thought that the heavy fishing to which the shoal is subjected 

 makes immigration necessary to maintain the herring population 

 of the fishing ground. 



