Translation Series No.1211

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oocytes can be demonstrated in the ovaries of salmon (Fig. 20 b, fish 43 to
54 cm long). (It is possible that the differentiation into these categories
had taken place already earlier.) Whereas the size of the recruitment oocytes
changes little during the subsequent time, the maturing oocytes show an
3
2
Oocytendurchmesser Diameter of oocytes
mm
Fork length
10 30 50 70 90
Crobelleg4grm
Fig. 20 b. Relation between fork length and diameter of maturing oocytes,
Nov. 1959,. length distribution of the sea year classes: "A.1+, 57 to 77
cm, A.24., 82 to 97 cm, A.+, 43 to 54 cm.
almost linear increase" in their diameter that is correlated with the length
of the fish (Fig. 20 h) until the second winter of their life in the Baltic
Sea. During the progress of the growth of the oocytes this correlation does
[p. 2721
no longer exist later (Figs. 20 a, c). Salmon who have a diameter of the
oocytes of more than 1.2 mm spawn already in the approaching fall4"that
is, after a stay of 2.5 years in the sea. The other fish proPagate a year .
later (Fig. 21). A Resell. (1893) gives a table of the egg maturation during
the course of a year in his_investigation of the salmon in the Elbe. The
values given for the months February to November fit excellently the curve
for the age class A.3 in Fig. 21. Fritsch, however, did not state the age
of his fish.
It becomes clear in general from the data for April (Figs. 20