66 
WINTER RINGS. 
Winter Rings. 2 3 4 5 6 7 8 9 10 
Percentages ... 1 6 16 52 9 5 : 
A further sample taken in the first week of July gave a much 
different age composition, and consisted of mixed fish, recovering 
spents, developing herrings and virgins. The growth varied 
considerably, from fish with an oceanic growth-to those with a 
very slow growth. This sample indicated that the recovery of 
the fishery was due to migrations. 
One of the chief difficulties in considering a fishery like that 
of the west of the Shetlands is the origin of the larval herrings 
which drift towards the coast. Spawning grounds we know exist 
between Lewis and the Shetlands, and it would require little 
change in the direction of drift for the young fish to miss the west 
coast of the islands. 
Tue WasH.—An example of the effect of drift on the distri- 
bution of young herrings is afforded by the Wash. Mr. Donnison, 
Inspector, Eastern Sea Fisheries District, in reply to a query 
about sprats and young herrings in the Wash in May, 1920, wrote 
as follows :—* Sprats and young herrings have practically missed 
this district for some years. | have known 100 tons to be brought 
to Boston on one tide. The fishing gradually fell off until the 
men did not care to fit out for it.” 
It is considered that sufficient evidence has been produced 
to show that the conditions which govern the herring fishery are 
widespread, and may extend over the whole of the North Atlantic, 
and also that in some periods what may be considered as minor 
fluctuations in oceanic circulation bring about local changes. 
MrcRaTIons.—We know little of the migrations of the herring, 
and the following is written with the idea of showing the probability 
of increasing our knowledge by a consideration of statistics and 
trade descriptions relating to catches. 
In the early months of the year, January to March, catches 
are made from shoals of spring spawning fish from the north-west 
of Ireland, about the north of Scotland, including the Shetlands 
and Orkneys, and in the Firth of Forth. This fishery is followed 
in April by a fishery for spent herrings which, in the North Sea, 
are caught by drifter liners for the purpose of bait, practically 
