Translation Series No.1211

Opcytenzet
Numbep
20
I0
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formation of mature ova. The strong growth of the female sexual products
through increase in the amount of cell content and through yolk deposition
and water uptake takes place after the diplonema stage of chromosome cor›-
jugation and before meiosis. Since this process can also be observed during .
the periodic - attainment of -spawning maturation in the second period of
life, it can be assumed that in the sexual cycle of adult fish maturation
begins with the enlargement of the oocytes.
.
The stock of salmon in the Baltic Sea is composed almost exclus-
ively of such fish that are in the first period of life and have nôt yet
spawned. The fish of the age class A.1+ have atill almost one or two years
of sojourn in the sea ahead of them and must be designated as juveniles
in the customary sense.
In the following it will be - examined whether the ovaries undergo
a change in the sea, and whether it is posàble to ascertain the probable
time of spawning already at this stage.
3.2.1. The ovary
of oocytes ,
, . . ,
,
, f
1
■
, ..• .
I ■ .
I
.. •
—■
ttesch.u. Cen %re diees
End discs .
,
Fig. 15. Size of egg in different regions of the ovary
. (means of 12 salmon, 74 to 79 cm total length).
• The ovary conditions were investigated in 68 females that were
) .
from 43 to 104 cm long. Three fish were in the first year of their star
in the Baltic Sea, 31 fdsh were in their second year and 34 fish were in
».11
20 mm
Egg- diameter
•
Enturchmesser