Translation 2783

• 142
•ith the onset of autumn frosts and .tne approacn of winter,
when the coastal zone of the sea begins to be ice-covered, the seal s .
on the fast ice or on floating ice near the coas. t..
her make breathing-holes in the ice, which they use all winter.
winter tney spend the greater part of the time in te water, where
There
concentrate
the temperature is more constant. It . has been observed that not all
adult seals spend t • o ,inter in their•former breeding areas. Some of.
thon go out into the open sea, where they live on •drift-ice.
sexually-mature females return every sprin t ; to toe breedini, areas.
Two views are held regarding the location of sexually-immature *seals:
some investigators hold that there are no juveniles in the adults'.
breeding areas (e.g.• a% I.cMurdo station); others believe that they
live_on the ice together with tue adults (in tue region of Mirnyi
station). The biology of sexually-immature Weddell's seals has not
yet been investigated.
The life of Weddell's seals is much shorter-than that of many
other members of the family Phocidae.
The
In
Some investigators belieVe that
they live to a maximum age of 16 years, and •that the average duration
of life is eight years.
Some of the.pups die as a result of tile break-up of ire-floes
and from other causes.
Among internal parasites, fla%worms and
roundworms have been observed; . altogether 20 helminth species have
been recorded, including six species of nematodes. It has •also been
suggested.tnat one of the mortality factors may be rapid wearing-down
of the animals' teeth. .
Weddell's seal is a dweller in the coastal zone and, above .
all, in the fast-ice zone.
Observations made .at Antarctic stations
indicate that those animals do not form concentrations on the ice,
but occur singly and less often in small groups. According to American
investigators, in 1968 tue number of seals,in Weddell Sea varied
•rom 0.1 to 2.5 animals per square . nautical mile
It has been observed that in several parts of the Antarctic..
fast ice Weddell's seals . are entirely absent. •L . hey also do not form
large concentrations on toe sub-Antarctic iiaands; usually tney lie .
singly, at a djotance from one another, or in small groups. Oase s .
are known os' larTe groups of theme seals, -
seen on the shore.
numberin„; lup to 250, being
tenent data on tue distribution of , eddells
seals in various regions of the Antarctic sugest that their total
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