Translation 2783

• 267
In the Sea of jaoan lesser rorquals feed mainly on krill,
but at Hokkaido they feed on fishes (walleye pollock, etc.) and
crustaceans; in the Pacific Ocean thoy usually feed on crustaceans,
an.' less often on sand-eels and anchovies. They also eat herring,
capelin, and navaga.
The males attain sexual maturity at a length of 6.7 metres
and the females at -7.3 metres, when they are two years old. The
peak of the mating period comes at the end of February and the beginningsof
March, and the peak of parturition at the end of December
and the beginning of January, after
gestation lasting ) perhaf
nine months. lew-born calves are about 2.8 metres long; they are
milk-fed for less than six months. By the end of the lactation
period they have attained a length of about 4.5 metres.
Besides the main mating period there is a second one half a,
year later. The females bring forth young almost every year; some
do so 18 months after the previous pregnancy.
The behaviour of these whales is in many respects the .same
as that of lesser rorquals in the North Atlantic, There are frequent
records of them entering river estuaries and getting entangled in
fishermen's nets, They do not avoid ice, but when there is ice on
shallow water they do not dive. Their spout has an unpleasant smell.
The presence of crustacean parasites on their bodies is very
seldom recorded. Their internal parasites include helminths, mainly
in the stomach and intestine. Their diseases have not been studied.
.Instances of attack by groupe of killer whales, terminating
as a rule in the death of the lesser rorquals, have been recorded.
The lesser rorqual is the first species among baleen whales
to have been kept successfully in an oceanarium. In the city of
Mito, in Japan, a lesser rorqual lived for three months in 1936, and
another, 6.0 metres long, survived for 57 days in 1955-56.
In the northern part of the Pacific Ocean the hunting.of
lesser rorquals is most highly developed on the coast of japan.
From 512 to 532 are taken in a season. Data on the take are presented
in Appendix 12.
The products are generally the same as those obtained from •
lesser rorouals in the Lorth Atlantic. The weight of a female 7.9
metres in lenc:th was 4,S46 kg
The status of the stocks has not been determined.