Environmental Engineering Reference
In-Depth Information
Rogue Reef, Three Arch Rocks, Cascade Head
and Shell Island of Simpson reef. Stellar sea lions
(
weight.
Sea otters
inhabit the northern Paci
c
Ocean. Instead, of thick layers of blubber, this
animal has a thick coat of fur to keep it warm.
Sea otters mainly stay close to shores, favouring
areas near coral reefs and kelp beds. They are on
the verge of extinction on account of hunting,
because of their valuable fur, and are now com-
ing back after international protective measures
were enacted.
c
Ocean from Japan to southern California. This
species has a tendency to remain offshore or haul-
out in unpopulated areas. Stellar sea lions aremuch
larger and lighter in colour than California sea
lions. The males weigh up to 2,200 pounds and can
be 8
Eumetopias jubatus
) are found in the Paci
11 ft, while the females are comparatively
smaller weighing around 600
(Eurasian otter) has
been documented in Indian Sundarbans.
Lutra lutra
-
-
800 pounds and
growing up to 6
8 ft long. Stellar sea lions roar
rather than bark and are much larger and lighter in
colour than California sea lions. Presence of a
thick neck representing a lion
-
Order Sirenia
The bulky lethargic small-brained dugongs and
manatees collectively called sirenians are the
only herbivorous marine mammals. They spend
their life grazing on seagrasses, marine algae and
estuarine plants in coastal temperate and tropical
waters of North America, Asia and Africa. Some
species also live in fresh water. The largest
sirenians reach 4.5 m (15 ft) in length and weigh
680 kg. Sirenians have been hunted extensively,
and only 10,000 individuals are now thought to
exist worldwide.
Manatees and dugongs
represent sirenians.
These animals were widely distributed at times in
the past, but they are now restricted to coastal areas
and estuaries of the tropics. The primary differences
between manatees and dugongs are in anatomy and
habitat. Manatees inhabit both the sea and inland
rivers and lakes. Dugongs are strictly marine
mammals living in coastal areas, where they can
feed on shallow water grasses. The head of the
dugong is larger and the
s mane is a striking
characteristic of the species. The breeding grounds
of stellar sea lions occur along the north Paci
'
c
Rim from Ario Nuevo Island in Central California
to the Kuril Islands, north of Japan, with the
greatest concentration in the Gulf of Alaska and
the Aleutian Islands.
Walruses
are much larger than either seals or
sea lions and may reach an average weight of
1,800 kg. Walruses resemble true seals
—
they too
have no external ears. But the true seal and the eared
seal have 18 teeth, while walruses have 34. Wal-
ruses can walk on their four
ns unlike other
pinnipeds, which have to drag their body around.
Despite having a heavy body, a walrus can move as
fast as man. The Paci
c walrus inhabits the coast
along the Berring Sea and its neighbouring waters,
while the ones in the Atlantic are found in the Arctic
from the Kara Sea till the Hudson Bay. Walruses
have tusks, which can grow as long as 68 cm and is
seen among both males and females. The thicker
and longer the tusk, the higher is the bull
ippers are shorter than
those of the manatee. The dugong
fl
'
srank.
Walruses also use their tusks to pull themselves out
of water and crack breathing holes in the ice during
harsh, cold winters. Walruses usually feed on
'
stailisnotched,
whereas the manatee
stailisrounded.
There are three species of
manatee
. The
northern manatee (
'
) is found
from the south-eastern United States to northern
South America. The Brazilian manatee (
Trichechis manatus
shes, crustaceans, echinoderms and molluscs. At
times, these animals were slaughtered for their
ivory tusks but now law protects them.
The suborder
Fissipedia
includes only one
ideal marine representative known as the
sea
otter
. The otters rarely exceed 120 cm in length,
eat voraciously, playful and intelligent. Their
daily diet includes molluscs, echinoderms, crus-
taceans, which constitute 20 % of their body
Triche-
chis inunguis
) is a freshwater species endemic to
the Amazon and Orinoco rivers. The African
manatee (
) is found in
coastal habitats, rivers and lakes of western
Africa. All three species of manatee have been
extensively hunted and law in Florida now pro-
tects the northern species.
Trichechis senegalensis
