Translation Series No.1211

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is true, have to be corrected only in regard to the wind conditions. During
the years 1955 to 1963 winds of over.4 Beaufort prevailed only on about 15
per cent of all days with net catches. For safety reasons fewer nets were
set on such days than on other days. Thus, if we neglect the results for
wind speed of over 4 Beaufort, the correction for wind speed of the net
catches has already been carried out. In order to eliminate a possible
[p. 255]
effect of the wind direction, every monthly value is formed as the simple
mean of the data for the four wind directions and calm. The mean for the
cz,tek
months February to April represents then the eapturTe per unit effort of a
season (Appendix, Table II). For 1956 and 1963 only results for April are
'available, which havelben corrected with the aid of the average monthly
trends (Table 7)..
The monthly means for the line catches can be calculated accor-
ding to the points 1 to 3 Of the above scheme. It is considered that a cor
rectiOn for food sùpply of the available data would be out of place, be-
cause the exact connection between line and net catches cannot be ascer-
tained at present.
In Table 15 have been entered the corrected net and line catches
alongside the uncorrected:mean Values according to . Table 7. A àraphic
presentation of the line catches shows that there is no correlation.iThe
correlation coefficient is r 11 0.22 ± 0 .27 6 .
According to the above discussions, we can indeed say that'the
cate.e.e..s
.-claria4zees Per unit effort by net have probably the smallest errors, we do
not know, however, whether they can be considered to be representative for
the entire season. Therefore, the data for the two kinds of gear offer
only a support. The improved values that are being added annually will
contribute to perfect Our knowledge of the extent of the stock of salmon