Translation Series No.1211

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The conclusions that have been drawn from Table 32, will remain
unchanged in any case even if the mortality is dependent on size. Because
the smaller fish fall prey to predators only during the first monthS, all
values would be slightly lower. For the saine reason it is possible to com-
pare the mean smolt age of all fish in different fishing seasons with one
another. It is found that the fluctuation are very small and amount at
most to 0.25 years. The lowest smolt age could be established as 2.54 and
2.51 years, respectively, in January195 8 and April 1963. It was . highest
with 2.78 years in January 1962 (Table 31).
yeee - cLue s
It might now be attempted to compare the brood y---set. with .
one another in regard to their average smolt age (Table 31). Since age
-yet.e-eieLes
*analyses for the entire life in the sea are available only for the year l o
of 1955, a period of that length cannot be used as the basis for a
yew-eLss
comparison. It is true that this is not necessary, because a brood year's
ite4..plays : a role for the catch only during five years and is of importance
even for three years only. More than 90 per cent of the tetal-yields from
yea. - 'J
a yeeeLs-set are obtained during this period.
yeev - S
Let us consider first the year's-meta that can be followed com-
'yeee -akcs
paratively for five years, namely 1955 and 1956, and then the yearle-sete
yege-dA.s.r
1954 to 1957 that can be compared> for three years. For the yearts-set.
1955 is found an average smolt age of 2.36, 2.41 and 2.42 years, when 3,
5, or 6 years, respectively, are used as basis. On the other hand, the
etét.ee •
yesei-e-sett 1956 shows a smolt age of 2.93 or 2.82 years, respectively,
when 3 or 5 years of life are taken into account. Thus, the values change,
because the fish with a smolt age of one and five years are not taken care
of sufficiently in the composition that is obtained during the fourth to
'sixth years of life. The deviation, however, is not large so that wescan