Translation 2783

N
277
were 1,583 kg and 2,012 kg respectively, and that of a male 6.5
- metros in length was 5,270 kg. ,
Dall's Porpoise (Phocoenoides dalli) 181
Dallis porpoises are found both in the open sea and in
coastal waters. On the coast of America these porpoises are seen
in Lower California waters from October to June. In summer their
numbers increase farther north, particularly in the British Columbia
region and in the Gulf of Alaska. 'Ihey approach different parts of
the coast of Asia in pursuit of shoals of fishes. Migrations in
pursuit of salmon heading for their spawning-grounds are observed.
Their diet consists mainly of various species of cephalopods,
and to a lesser extent of fishes (capelin, herring, horse-mackerel,
etc.). In an ocennarium they consume from 15 to 20 kg of mackerel •
and horse-mackerel each per day.
The females attain sexual maturity at a body length of about
170 cm, and the males at 185 cm, at the age of three years or more.
Mating takes place in summer. The duration of gestation is slightly
less than a year. The embryo, which develops only in the left horn
of the uterus (the right ovary remains in the sexually-immature
condition) is about 100 cm long before birth. Birth takes place
from the middle of July to the first ten days of August. A female
embryo 77.5 cm long weighed 7.3 kg..
Both small groups of a few Dail's porpoises and herds of
some hundreds of the animals may be observed at sea. They readily
approach ships, and follow them at a speed of more than 11 knots
(sometimes up to 20 knots).
There is no special hunting for Dall's poroises. Japanese
fishermen in salmon-fishing fleets operating in the Bering Sea and
farther south (to the east and southeast of Kamchatka, between 46 °
and 60 ° If, as far as 175 ° W) are said to take up to 10,000 (!)
from their nets every year and to throw almost all of them back
into the sea without making any use of them ..
The weight of adult males measuring from 172-to 210 cm is
from 93 to 150 kc, and that of females measuring from 176 to 190
cm is from 100 to 135 kg.