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Most seals live
in the artics and survive in the harsh
and bitter cold weather because they
have a layer of thick fat called blubber.
Seals and sea lions live most of their
lives in the water but come out on
land to bask in the sun. They come
up during the breeding season. They
like deep salt water because it provides
plenty of fish to keep them alive
and healthy. Seals live in places
where disturbance is minimal. They
like islands and rocky shores where
they can bask in the sun and be close
to their source of food. Also, they
like sandbars, where they can also
bask in the sun. They feed in cold
open waters so that there is a wider
variety of fish to choose from.
The Antarctic Fur
Seal breeds in summer on islands ranging
from South Georgia at 70° W round
to about 80° E (Kerguelen Islands).
Additionally there is a breeding ground
at Macquarie Island, 165°E - south
of New Zealand. All of these islands
are between 45° S and 60°
S. The animal's winter range is not
known. During these long dark months,
the seal spends its time almost surely
close to the Antarctic ice —
spending virtually its time at sea.
A population count
is due in 2007 or 2008, and estimates
can only be very rough until this
is carried out. Best guesses suggest
there may be two to four million individuals
breeding at South Georgia and 15,000
at Heard Island. The concentrations
at South Georgia are the densest aggregations
of marine mammals on earth. Some people
believe these populations have grown
to such levels because the removal
of whales by the intensive whaling
of the 20th century left a surplus
of krill. Other islands in Antarctic
waters may have a few hundred to a
thousand such seals.
Characterized as
showing a strong degree of site fidelity
in their choice of resting sites,
they may spend several days at sea
and travel up to 50 kilometres in
search of feeding grounds, and will
also swim some distance upstream into
freshwater in large rivers. Resting
sites may be both rugged, rocky coasts
such as that of the Hebrides or the
shorelines of New England, or sandy
beaches. They also inhabit sandy intertidal
zones; some seals may also enter estuaries
in pursuit of their fish prey. Some
have even taken to feeding in New
York Harbor and Boston Harbor in recent
years. The seals frequently choose
to congregate in harbours, lending
the animals their other common name.
The feeding habits
have been studied closely in many
parts of their range; they are known
to prey primarily upon fish such as
menhaden, anchovy, sea bass, herring,
cod, whiting and flatfish, and occasionally
upon shrimp and squid. They are able
to dive for up to ten minutes, reaching
depths of 457 metres (approx 1500
feet) or more, but average dives may
be three minutes long at depths of
about 20 metres. |
