Translation Series No.1211

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and nape corresponds to a total length of 91 to 112 cm. Furthermore,
small as we ll as large fish, who are not retained by the net on account
of the body circumference, can become entangled in the net by their teeth
and may be captured in this manner.
According to what has just been said, one cannot expect a com-
plete selection for small as well as for very large fish ., whereas for a
mesh of 80 mm the highest selection can take place for lengths of between
about 74 cm and 92 to 112 cm.
In practice there are certain differences in selection that
depend on the material of the nets. It has already been mentioned that
the heavy hempen nets are not as effective as perlon nets (Table 2). In
a net of gynthetic fibres even those fish can still become entangled whose
circumferenOe at the head is greater than the mesh sise, since some of
them can become entangled in the thin net material, or become àtuck in the
fine yarn with their teeth.
Table 8. Selectivity of salmon driftnets with an average
mesh of 78.75 mm.
1 2 3 4 5
Total Number of salmon Net catch Tripartite Value of column 4
length Hook, Net Line catch adjustment when 7.5817 100
cm
52,5 ' 6
57,5 7 0,1895 2,50
62,5 31 17 0,5484 0,4038 5,32
67,5 92 61 0,6630 0,9607 12,67
72,5 82 137 1,6707 1,9969 26,33
77,5 35 128 3,6571 2,9759 39,21
82,5 20 . 72 3,6000 5,7267 75,50
87,5 13 129 9,9231 7,1991} 94,85
92,5 , 27 218 8,0741 8,4824 0 7,5817 111,90
97,5 20 149 7,4500 7,0636 93,08
102,5 6 34 5,6667 4,8722 64,25
107,5 2 3 1,5000 2,3889 31,50
112,5 1 0,5000 6,59
341 949