Translation Series No.1211

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however, not be compared directly with each other, so that the trend of
the development of the effort is not .easily seen. Therefore, the total lan-
dings have been re-calculated as values for hooks with the aid of the diary
entries.
There is an increase in the total effort by more than one-third
since the season of 1957/8. This deyelopment was interrupted by the col d .
winter of 1963, because the German cutters could not fish from January
until March 1963.
It is our goal to obtain an expression for the exploitation of
the stock of salmon. The extent of the exploitation is, however, dependent
not only on the number of the gear employed, but also on the spatial dis- .
of the effort and of the fish. That is, it will be necessary to tribution
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take into account besides the spatial distribution of the effort, also the
number of fish on the various fishing grounds. This value is the total ef-
fective fishing intensity. It is, however, not possible in our case to ob-
tain for this any values that are approximately correct, because it cannot
be ascertained how the entire fleet was . distributed over the fishing grounds
and what yields were obtained on the individual fishing grounds. This forces .
us to consider the effort as the measure : for the exploitation of the stock.
P. 240]
2.3.3.2. Catch per unit effort
In the above the yield of the fishery has been accepted as the
expression for the exploitation of the stock in order to make more plain
the role of the fishing effort. It can, however, easily be seèn that the
intensity of fishing is proportionaLto the exploitation only when the size •
of the stock remains constant. In contrast to this, a constant intensity
of. fishing can lead to strong depletion when the stock is very weak, whereas
it does diminish a strong stock only slightly. This shows that the intensity
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