Translation Series No.1211

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100
50
60
100 cm
Totallarle
.
20
d = '9 = ----, n ------ 997
= Total length.
Fig'. 12 .. Distribution of lengths and--gonati--1-ength-s—ef
crç Sal- e-ko
eke 1.3..êtqc, .seixtryaed., b
- 61 -
fresh-water bodies (Labrador, Maine), in Lake Ladoga and Lake Vânern.
Dahl (1914-26) found them arso in the lakes of the river Otra. These
[p . 261]
salmon live in land-locked waters that were formerly connected with the
sea. Their entire life is therefore spent in fresh water. Females and males
become mature there and migrate'into the rivers to spawn.
This knowledge showed that salmon do not absolutely require
the change of environment from fresh water to the sea and back. It came,
however, still as a Surprise when Danish fishermen succeeded in about 1925
in raising females from artificially fertilized eggs. These females matured
after four years in the fresh-water ponds and spawned three times in suc-
cession (V. O. Otterstr8m 1933). To be sure, the fish attained a length
Of only 42 cm after five years.
Anzahl Lackse = 'Number of salmon
.Recently . Swedish scientists succeeded in . repeating the ex-
periment and they have furthermore raised Atlantic salmon already to the
fourth generation in fresh water (pers. communication from B. Carlin).
However, the other extreme is also possible up to a certain
'degree. I know of four cases in which female saimon-of 1959 to 1964 with