Translation Series No.1211

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• been ascertained from them are dependent on the number of the emigrated
salmon and may perhaps be greater than stated. Finally, it is very probable
that thè differences in the mean lengths that have been ascertained for
the age groups of a sea year class would be greater when the emigrated
salmon have been taken into account. This could have the consequence that
the statistical treatment of the differences yields significant differences.
The possibility is therefore not to be rejected that the size of the smet may
influence thé length of the salmon in the sea.
6. The food of the salmon of
the Bal tic Sea
The manner of life of the fish is determined in many respects.
by their food.. Thus investigations of the food will suPply information
about certain habits and behaviour. Furthermore, changes in the kind and
, amount of the food consumed influence the composition of the tissues.
Finally, the food forms an important component of the factors that deter-
mine the growth.
• 6.1. Previous investigations
The differences between the life of the salmon in the rivers
and in the sea have also affected the food investigations'. It is easier
[P. 334]
to obtain the material for investigation in the rivers than in the sea.
There are therefore few papers that treat the nourishment of the adult
salmon. •
.6.1.1. The nutrition of the juvenile stages
The nutrition of the salmonids in fresh water has been investigated