Translation Series No.1211

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expenditure, composition in regard to age, and morphological, as well as
physiological characters that serve to define a stock. The last definitions
have been offered in connection with population-dynamical investigations.
For the quantitative consideration of a stock it is necessary to delimit
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lp. 346 ]
a stock less from a biological point of view than from the standpoint of
fishery, in order to ensure that the figures of yield that are used as
basis relate only to a definite population. •
In the present chapter an attempt will be made to carry thropgh
a quantitative, analysis of the stock. Let us assemble the . characters def-
ining the stock that have been cited above and apply them to the salmon
of the Baltic Sea.
A.uniform.stock ("unit stock") inhabits an area that iS frequently
. delimited tbpographically and propagates within this area of distribution.
It can be fished in continuous isolation. Exchange with other populations
has an insUbstantial.influence on the composition of the stock.
If wa now consider the Baltic Sea salmon, we can state at the
• outset that these fish are unambiguously confined in their distribution
(see 4. migrations). The-western Baltic Sea with the Belts forms the western'
boundary of distribution. An'exchange with other regions does praàtically.
not ciecur. Within the area, however, quite a number of rivers are visited
for spawning. This fact, however, does not justify to consider each river
population(as . its own stock, 'because the spawning fish together with other
individuals are- being exploited . in the Baltic Sea before their return . td
. .theirivérs. In addition, several investigators could show that the great
changes:that occur in ébe riverï oan be followed quite uniformly in all
• the others .(G. Alm 1928a, 1928b, 1958; N. llagmann 1938; T. H. anti 1938,
:1948;. Lindroth.1950, 1957; G. Svârdson 1957a).
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