by one-half, i.e. 24, making 71% of the large fish originate from Nordland fat 
herring. In a similar manner, the percentage for the spring herring was found to be 
48. This indicates that the spring herring shoals had recruited from fish of more south- 
erly origin to a greater degree than the large herring. Investigations as to the growth 
of the spring herring also show that a part of these must have grown faster than the Nord- 
land fish, maturing at an earlier age. Although the 1904 year class furnished so great 
a percentage of the spring herring both in 1908 and 1909, none of them were found to 
be marked. Not until 1910 did the marked Nordland herring make their appearanec 
among the spring shoals. 
In the south-western part of the Norwegian coastal waters, the herring mature 
at an age of 3 (though very rarely), 4, or 5 years, whereas in the northern waters maturity 
is only reached by any considerable number at an age of 5 or 6. It is thus extremely 
natural that the percentage of the 1904 year class in the spring shoals should have in- 
creased up to 1910 (when the fish were 6 years old). As will be seen from Fig. 24, 
a sample from the Faroes, examined in 1910, containing 51 % of the 1904 year class, 
was found to include marked fish, whereas samples from the same waters taken in 1908 
and 1909 revealed only a minimal quantity (less than 1 %,) of the 1904 class. These 
fish spawned in Faroe waters in 1910. As to how far any of them may later have joined 
the Norwegian spring shoals, nothing is known. 
Recapitulation. Sketch of the natural history of the herring. 
It may now perhaps not be out of place to give a rough outline of the life history 
of the herring in Norwegian coastal waters. 
The spawning shoals of spring herring, which are taken in West Coast waters, form 
a stock of very variable age and size. The youngest fish reaching maturity are three 
years old; these are, however very few in number. Of those fish which grow up in the 
southern waters, many join the spring shoals at an age of four years, the majority, ho- 
wever, probably a year later, whereas those of northern origin do not enter the spring 
class in any considerable numbers until they are six years old. The average size and 
age of the shoals vary according to the numbers of the years classes represented. We 
may therefore find small (young) spring fish with an average length of 27 or 28 cm., 
and larger (older) ones with an average length of 31, 32, and even 33cm. Previous ex- 
perience (year class 1899) seems to indicate that the spring herring do not, in any great 
numbers, reach a higher age than 10 years; the present material, however, clearly shows 
that the number of years here taken into consideration is too small to permit of our for- 
mulating any definite opinion as to this. Further investigations will here be necessary, 
and it will be not least interesting to observe how soon the 1904 year class will die out, 
i.e. what percentage it will form of the stock of spring fish during the next few years. 
The young fry are carried northward along the coast by the current. (The 
chart in Fig. 25 may here be used for comparison). They spread as if sown all along 
the extensive range of coast, and everywhere some small fish develope, beyond doubt 
mostly in the northern waters. In the autumn, when these small fry are 8—10 cm. 
long, and 2/, year old, or in the winter, at the age of about one year, when they are called 
“musse” or “kril?, they begin to make their appearance in the semes. Next spring they 
begin to grow again, in May, and soon become “bladsild” (12—15 em. long). Most of 
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