20 
PIVTH YEAR GROWTH. 
NUMBER AT CENTIMETRES. 
Winter : 
Sample. Trines DA) 26) 2 elon eo LOtal. 
Gazi PS A EMG h tS Ti a Sera 
MiGia wire.) Eee tie & As Ad 06tane == blades 
The age composition and development of the Firth of Forth 
sample compared with that of 1921, when so many herrings at the 
end of their third year were found in the sample examined, makes 
a comparison of the growth data desirable, and for this purpose 
the growth of both the 1921 and 1922 sample will be found in 
Table III. For first year growth the majority of the three winter 
ringed herring of the 1921 sample fall under centimetres 9 to 12, 
and four winter ringed fish in the 1922 sample are found chiefly 
under centimetres 8 to 11. For second and third year growth 
the majority of the fish will be found to be as follows :— 
Sample. Centimcetres, 
Second Year Growth ... 1921 18 to 21 
1922 17 to 20 
Third Year Growth _... 1921 23 to 25 
L922 22 to 24 
Data have been given* which show that variation in growth 
accompanies variation in maturity, and in last year’s Report it 
was stated that the difference in growth between fish with three 
and four winter rings in the Firth of Forth samples was taken as 
supporting the hypothesis that herrings, previous to reaching 
maturity, shoal according to size. From the data given above 
it appears that of the 1918 year-class it was the herrings which had 
made a comparatively rapid growth which joined the spring 
spawning shoals of 1921, and that the fish which had not grown 
so rapidly did not join the spawning shoals until a year later. 
The growth made by the herrings of five winter rings in the 
sample of 1922 is much the same as that for fish with four winter 
Tings in the 1921 sample. It cannot be said that this year-class, 
1917, has given any noticeable additions in 1922 to the spring 
spawning shoals of the Forth. 
The Girvan samples are the first which have been examined 
from the Clyde fishery, which has been a failure for so many years. 

* Report, New Series IX., 
