— 117 — 
separate groups. The averages for all years show approximately the same number of 
loddefisk and skrei. The former is, in three of the years, represented by over 70 % (in 
one over 80 %), the skrei also, in one year, amounting to over 80 %. 
Loddefisk (under 65 cm.)  Skrei (over 65 cm.) 
Under 50—64 All under Allover 65—79 Over 
50 cm. cm. 65 cm. 65 cm. cm. 80 cm. 
TOR 22.9 52.8 75.4 24.3 OAI 5.2 
ODA 2.8 41.3 44.1 55.9 45.0 10.9 
AO : 50000 117.9 26.2 44.1 55.9 23.8 30.1 
IOS eos. 6.0 26.7 32:7 67.5 34.3 33.2 
iO OM eee as 28.6 46.0 74.6 25.4 19,7 2.7 
WD occace 6.9 73.5 80.4 19% 15.9 3.8 
IIB , © 00 0 0 0.9 18.2 19.1 81.0 56.5 24.5 
All years.. 12.2 40.5 52.7 47.2 30.9 16.3 
Within the loddefisk group again, I have distinguished a special subdivision, that 
of fish under 50 cm., varying in different years from 0.9 to 28.6 %. The corresponding 
field of variation for the groups from 50 to 64cm. lies between 18.2 and 73.5 %. 
If we now proceed to consider the different years in chronological order, we notice 
that the series begins in 1901 with a high percentage of loddefisk and a low percent age 
of skrei. Thence up to 1906 inclusive, the percentage of the former decreases, that of 
the skrei, on the other hand, increasing. From 1906 to 1909 we find a new increase in 
the percentage of loddefisk, with a corresponding decrease on the part of the skrei; from 
1909 to 1913 the reverse is the case. ( 
It is evident that these extremely complicated conditions must be due to various 
factors. The following possibilities immediately suggest themselves: an immigration of 
small fish into the shoals of the loddefisk, an emigration of Finmark fish joining the shoals 
of skrei, a movement of skrei from the spawning banks to Finmark waters. Each of 
these various points must be separately studied and elucidated. Before proceeding to 
further discussion of these fluctuations, however, we may glance at some typical varia- 
tions in point of size within one and the same year, thereafter, by observation of the 
age and growth of the fish, endeavouring to ascertain how soon one group can pass into 
another. 
Variation in size of the Finmark fish in one and the same year. 
We have previously referred to the fact that the Finmark stock must be regarded 
as consisting of two component parts, the loddefisk and the skrei. If we now compare, 
not only the average size of the Finmark fish as exhibited by the total of samples for 
a single year, but also the different samples one with another, we find that these are 
not invariably “mixed”; some of them are “pure” samples of one or other of the two 
components. This we might almost have deduced already from the table on p.115. And 
we now find, that both cases may arise, either an early arrival of the loddefisk (during 
the first part of the season) the skrei making their appearance later on, or an exclusive 
predominance of the skrei in spring, the others delaying their arrival until well on in the 
