Translation 2783

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of i:a.rch to the middle of ];a y. Copulation may take place both on
the ice ' and in the water. After fertilization the:ce' is a pause in
the development of the ova, lasting for 3-3.5 months. ',,:4re total
duration of gestation is about 11 months.
r, very snall proportion of the females mate. on attaining the
a^,e of five years, and the r.e:,ir:.inder at six years of a.-e.' The major
ity of fertile females take an active part.in reproduction before
they are eight years old. it is believed. th.;t sexu'ally--matu-re females
do not mrite every year, and the percenta^e of barren females may
reach a hin,h fil,,ure.
The moulting period of ringed soals bec,;ins at the end of
sprin- and lasts all through tiie sumnier. At that tirae the animals
form scattered groups both on fast ice and on large drift-ice masses.
f'he period of most intensive feeding begins after the moult
is completed, although the anir_1^.ls also feed durinr; other bioloÛical
periods of tiieïr lives.
The principal items in tiieir diet consist
of various species of small pelagic crustaceans and small fishes.
The conipositioi: of the diet may vary according to the locality. Up
to 72 food items have been found in the stomachs of these seals in
eastern Canadian waters, the predominant items being .^uphausi.acea,
Mysidacea, Amphipoda, and shrimps; Arctic cod took a prominent place
among the fishes eaten.
In the waters of the Eux'onean North rir.;ed seals feed on small.
crustaceans and fishes. In some areas Arctic cod is the chief' fish
species eaten (more than 90;u). The seals also feed on sand eels,
capelin, smelts, and flatfish. Crustaceans predornina te in the diet
in summer and fishes in winter. In the White and barcnts .Aa..s rin;ed
seals also eat s-veral species of commercial fishes, such. as navaga
30
and herring; and in ,::ome rivers in the Kola Peninrula they pursue
salmon durint• the period of salmon mi(,-ration, formi.n,-; fairly larÉ;e
concentrations. It is believed that the total -cle.,_?..^;e done there to
valuabli: snecies of commercial fishes is ne^;1.i^,ibl.e. In the Baltic
Sea ri.n;;ecl Leal:-, eat Ûo].nton, -i^o..l.tic heri'int;, sprat;;, cod, 1)i.l e-perch,
ee7.:,, and whitefish, and ai)pai.-ently do some to commercial
fi^her:Ce,a in that ro.-ion. i,in^•rd seals feed iuainlyin coa:,tal waters,
but tire,y may dive to a dc.nth of up to 1U0 i.rutroa in i,oa:i.,ch of food.
in lirctic waters l,it,: c,riu.i onom,y o.t' tnc :i-,à.n,,cd :.(!al