Translation Series No.1211

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November to March for forming the mean value. Since sufficient data for
driftnet fishing are available only from February onwards, it will be
best to use the period February till April for the calculation of the
representative carbtiee per unit effort.
°led,
An exact correction for the cap-titre-per unit effort by line
in regard to the wind conditions could be made in the following manner.
1. All data for each of the months November to March are to be divided
into those for wind speeds above and below 5 Beaufort, and then sep-
arated according to the four wind directions.
2. It is possible to eliminate the wind effect by calculating the mean(Pf
ç'th-
the five data)for the wind directions and calm. This provides corrected
values for each month above and below 5 Beaufort.
3. A mean monthly value can be calculated from these data for the two
wind speeds.
4. The monthly trend of the melees per unit effôrt that is now available
must be corrected in regard tb the food . supply through the comparison
of net and line catches for the months February/March.
5. Finally the arithmetic mean Of the data for the months November to
March has to be calculated.
When a complicated procedure of correction as —that outlined here
Is to have any meaning, it will be necessary that the individual data menm
tioned under point 1 are based on representative catches. Each of these
statementà must have the same statistical value as the finally calcula,ted.
yearly mean value. However, for the present material this does not hold
true: The result of a correction as outlined above can . therefore be used
only with reservations. '
•
To begin with, let us inspect first the net catches, which, it