Greinar (Vísindafélag Íslendinga) - 01.01.1943, Page 200

196
Finally, it should be pointed out, that in the material
from Keflavík, which is by far the best of the two samples,
I have found a slight difference between the different
age-groups, the number of vertebrae in the females
showing a tendency to increase with age. The results ob-
tained are these:
2 years old: N = 15; M = 69.200 ± 0.490
N = 479; M = 69.489 ± 0.041
N = 21; M = 69.571 ± 0.127
N = 2; M = 69.500 ± 0.357
3
4
5
Apart from the M5 = 69.500, which is only based upon
2 individuals, the correlations between age and number
of vertebrae seem very clear, and is not difficult to ex-
plain. The capelins spawning time is extended over many
months, about half a year, because which the latest-
hatched individuals must have reached much less size at
the end of the first growing period than those, that were
hatched first. Further, the latest-hatched individuals
grow up in colder waters than the others, and it will
therefore take them a year or a longer time more to reach
the stage of maturity than their companions. All this is
in accordonce with a higher number of vertebrae, or an
origin from colder water for the older age-groups.
U- The Relative Number of Males and Females. In the
three samples, I have examined as to sex, the number
of males has amounted to only a fraction of the whole
material. The material from Keflavík comprised 4918
individuals in all, of which all but 71, were females.
Of the Hvalfj.-material, June 24th 1939, 93 were sex-
determined, and only 2 males found. Finally, there were
8 males, in a sample of 205 individuals investigated from
Hvalfj., April 2nd 1939. The percentage of males and fe-
males in these three cases was therefore:
1938 M. 1.4 F. 98.6 Keflavík Apr. lst
1939 — 2.2 — 97.8 Hvalfj. June 24th
1939 — 3.4 — 96.6 Hvalfj. Apr. 2nd