71 
From a consideration of first year growth the changes in 
the herrings on our fishing grounds oft Northumberland have 
been stated to be as follows.* Herrings with a comparatively 
small first year growth appeared on the grounds in the latter 
part of June and early July. Towards the end of July and in 
August fish with a comparatively large first year growth were 
more abundant, and in September the samples have been marked 
by the number of fish with a comparatively small first year growth. 
These changes in the shoals coincide with the catches made 
and the data here given suggest the possibility of timing the 
arrival of the herrings on the grounds. 
The close agreement between catches and movements of 
herrings to the Northumberland grounds as determined from growth - 
data, and changes in growth data observed in other shoals during 
the season,+ suggested the possibility of comparing the North 
Shields catches with those made from other ports. 
The catches landed in 1920 at North Shields, Scarborough, 
Grimsby and Great Yarmouth, as well as those made by Dutch 
luggers, are shown graphically in Figure If. : 
It will be observed that during July, August and September 
there is considerable agreement between the curves representing 
the North Shields catches (Northumberland coast) and those made 
by Dutch luggers in the vicinity of the Dogger Bank. Both curves 
show rises and falls in the catches, separated by the same intervals 
of time, but the highest catches made in the vicinity of the Dogger 
Bank are a week later than those made in Northumberland waters. 
After 25th September the North Shields catches were made 
chiefly off Whitby and Scarborough. 
The rise in catches made by Dutch luggers for the week ending 
25th September is followed a week later by an enormous increas 
in the catches made by vessels fishing out of Grimsby, and to a 
less extent by those made by Scarborough vessels. 
When the increase took place in September the Dutch luggers 
were fishing in an area bounded by 54° to 55° N., 1° to 2° E., and 
» the Grimsby vessels in 53° 30’ to 54° N., 0° 30’ to 1° 30’ E. The 

* Reports, New Serics VII. and IX., pp. 37, 25-31. 
7 Report, New Series IX., pp. 25-26. 
