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Values of Biological Diversity
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Hạ
Long Bay has a very complicated structure with its meandering
coastline and many river mouths. Rich and diversified sources of
food for many species of plants and animals are also found here.
In particular, the bay, partitioned by thousands of large and
small islands, creates areas of water with an average and stable
sea level. Meanwhile, the climate in Hạ Long Bay is also very
stable, with an average temperature of between 19 and 25ºC, and
an average heat radiation rate of 17 kcal/ sq. cm/ month. It sees
an average rainfall of 2,000 to 2,200 mm/ year. These
favourable conditions have seen the development of many varied
ecosystems.
Results
of scientific research show that Hạ Long Bay features ecosystems
of a tropical ocean region, such as: salt water-flooded forests,
coral reefs and tropical rain forests.
In
the sea surrounding Hạ Long, coral grows in many places, but is
densely concentrated on the eastern and southern sides, far from
the mainland. According to research conducted by scientists from
the Oceanographic Institute, Hạ Long Bay is home to 163 species of
coral, from 44 lines of descent and 12 families.
Coral reefs are distributed everywhere, generally at a
depth of 4 to 6m. The coverage rate of coral reef is 30% on
average, but there are areas where it attains 70 to 80%, such as
at Cống Ðỏ and Bọ Hung. The coral forests of Hạ Long Bay are a
wonderful sight, with many extraordinary shapes and diversified
colours. When the tide flows, the coral moves with the water,
pumping as rhythmically as a heartbeat. At the same time, the
reefs are residence to a great number of species: fish (107
varieties), water plants, algae and transitory animals and plants.
The
salt water-flooded forests also offer especially interesting
scenery along the coastline of Hạ Long Bay. These forests are
chiefly concentrated in the zones of Tuần
Châu, Cửa Lục
and Ba Chẽ. Many species of salt
water-flooded plants, the most diversified collection in North
Vietnam, are found here. Also living in these flooded forests are
a great many species of animals: migrating birds (37 species),
sea-bottom animals (81 species) and fish (90 species belonging to
55 families). In particular, bottom-feeders account for 61% of the
total species in the whole tidal region, with many species being
of great economic value: arcae, meretrixes and all kinds of
crustaceans.
The
tropical rain forest ecosystem also features a rich quantity of
species: đinh, hương,
sến, táu trees. This is the
residence of various rare and precious creatures: deer, weasels,
squirrels and in particular, white-tabby and red-haired monkeys.
At
the same time, there is a system of small caves along the sea,
which are the living and development places for many animals and
plants: seaweed, water plants, algae, fish and shrimp. Deeper into
the water, there are also many species of shrimp, fish (almost
1,000 species), abalone and other sea-specialities; harvested
every year to the tune of several thousand tons.
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