— 173 — 
7 8 9 10 11 12 13 14 cm 
IQ... 49 il, 25.7 33.6 18.7 7.2 0.7 0:6 
NOOO ceed 88 2.0 Toe) 37.2 38.7 10.9 a0 7 
THON AURES PAIE ARE: 1171 33.1 26.1 19.0 N ied 
It will be noticed that there were far more small fish (7—9 cm.) in 1908 than in the 
other two years. In 1909 the fish consisted almost exclusively of individuals of 10—11 
cm. long, whereas in 1910 the sizes were more evenly distributed among the groups from 
9—12 cm. These fluctuations are of great importance in the practical industry, the varia- 
tions in the size of the sprat being often regarded as variations in quality. 
9 
8 
7 
6 
5 
4 
3 
2 
| 
673 9 MMR 0 23845 678 © Dl RP F1 2 3 Æ 5 6 7 
Fig. 104. Amount of fat in West Coast sprat; mean percentages for each month. 
x mean surface temperature of the sea for the month, taken at Helliséy, near Bergen (Sunp). 
On examination, it was found that the fluctuations in size were here, as in so many 
other cases, due to a difference in the composition with regard to age, or to the different 
numerical value of the year classes represented. Oscar Sun», in the work above referred 
to, gives the following table showing the composition in point of age of the stock of 
sprat in the Norwegian fiords during the years 1908—1910: 
From samples Group I Group II Groups Ill and IV 
examined in Averagelength No. % Average length No. % No. % 
OS ae lanes 10.15 90.6 11.73 6.4 3.0 
1909—1910...... 10.20 22.7 11.09 74.8 2.5 
A very great difference is here noticeable in the composition with regard to age, 
which would seem to indicate that the species is subject to great and rapid changes in 
this respect, “possibly greater than is the case with any other of our food fishes, a pheno- 
menon which may doubtless be explained as chiefly due to the shorter life of the fish”. 
