Translation Series No.1211

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whereas the present data .(1957 to 1963) give 2.A per cent.
- 145 -
R. Kgndler and M. Lehman (1957) have already pointed out that
the share of the salmon with spawning marks 1epends on the age composition
of the sample of catch examined. The older the salmon are that have been
caught, the more specimens with spawning marks will be found among them.
This furnishes also the partial explanation for the fluctuations of the
values in Table 36, when one compares them with the composition in age.
Furthermore, it becomes also clear why G. Alm (1934) and T. H. and (1938)
[P. .315]
found the high percentages of 7.5 and 6.3 per cent, respectively, of salmon
who were spawning again. The percentage of fish with spawning marks in the
total catch thus gives hardly any information other than that obtained
anyway through age determinations. On the other hand, one can answer other,
important, questions:
(1) At which age do salmon migrate to spawn?
(2) How grèat is the percentage of fish with spawning marks in the indiv-
idual age groups?
(3) What percentage of the utilized stock migrate to spawn?
In Table 37 the fish with spawning marks have been divided ac-
cording to time of'spawning and the age at spawning. - The number of fish
that did sPawn in 1962 could not not be taken into account completely,
[p. 316]
because all survivors had not yet returned by the time of the last examin-
ation (spring of 1963); On the other hand, the number of the older fish had
already been reduced through mortality. If we compare the total result with
the age compositions for the years 1957 to 1961 that have been investigated
best, .there is found no substantial difference. About 50 per cent of all
fish on spawning migration consisted of fish that were in the third
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