Translation 2783

..... 20 6
: r. Là}..^ Je and in the Porto Alexandre region at the
of ,:une, ;i t;i a, rca.l: in :.re ?niC,cle of Ju].y. The first
hutllp-ba.ck i•!h£l,les a3.-,:tL?ear of.:.' the l•.T"rtS^ coast of Australia in June.
The first of them reeach the coast of eastern Australia at the end
of May. They pass ?ieti•r Zealand from ^.Ia.Jr to August, with a peak in
the middle of Ji.i_ne.
The rate of travel of adults during the northward migration
is from two to four knots, and. that of females with calves is 1.5
or two knots. They stay in the breeding areas from 1.5 to 3 months.
Hump-back whales reï::ain in Antarctic waters from three to
five months, fattening in areas of krill concentration; krill forms _
practically thnir sole item of diet, as with other baleen whales.
Only in more northerly regioTls is krill replaced by other species
of Eu??hausiacea.
In the fattenin,;--Y,rounds hu:tip-back whales are found both at
the edge of the ice-field and in the open parts of the sea, even
among numerous icebergs.
They eat five or six times a clay (every
three or four hours). Their stomachs contain from 500 to 750 kg of
food, and sometii:ies even up to 900 or 950 kg. During its sojourn
in Antarctic waters an adult hun,p-bac.k whale cons-ames u,^p to 450
tons of crustaceans.
In winter hump-back whales ap.parently feed much less often
and on smaller amounts of concentra.tion-forming organisms, such as
crustaceans and a few fish species.
There are two races of hump-ba.ck whales in the southern
hemisphere. In the larger race, which includes the South Georgian,
West African, and. East African herds, the males attain se.tiual maturity
at a body length of 11.9 metres, and the females at 12.4 metres.
Hating tak.es place within a relatively short period of time (two or
three months).
Gestation lasts for more than 11 months. The average
length of a new-born calf is 4.7 metres (most are from 4-5 to 4-9
metres). 'l'hey are suckled for about six months. By the end of the
lactation period they have attained a length of eight or nine metres.
Most of the adults mate almost every year, mainlÿ in July and Iiùgllst.
The hump-back whales of the Australia-Yew Zealand-Peru ^;rou1i
bccome sexually mature at the folloi.rin{, minimum body lengths; :Aa les
11.2 metres, females 11.7 metres.