Pesut Dolphin and Habitat in East Kalimantan, Indonesia
BY RAMADIANI
“Pesut”
is belong to Irrawaddy dolphins class,
therefore, although living in the water, the dolphins are not fish but mammals.
Irrawaddy (Orcaela brevirostris) is one of the mammals that live in water,
breathe using lungs and reproduce by means of delivery. Adult dolphins have an
average weight between 90-200 kg with a length between 2 to 2.7 meters and
gray. In
general, the world knows “Pesut”
as the name of the Irrawaddy Dolphin. That name refers to
one of the sub populations located in the Irrawaddy river / Ayeryawaddy in
Myanmar, Southeast Asia.
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| A map of Irrawady dolphin location |
Overall,
the dolphins' color is grey to dark slate blue, paler underneath, with no
distinctive pattern. The dorsal fin is small and rounded behind the middle of
the back. The forehead is high and rounded; the beak is lacking. The flippers
are broad and rounded. The species found in Borneo, the finless porpoise, Neophocaena
phocaenoides, is similar and has no back fin; the humpback dolphin, Sausa
chinensis, is larger, has a longer beak and a larger dorsal fin. Vernacular
names for O. brevirostris include the following.
•
Burmese: labai
•
Chilika
dialect: baslnyya magar or bhuasuni magar (lit. oil-yielding
dolphin)
•
Filipino: lampasut
•
Indonesia: pesut
•
Lao: pha’ka
•
Oriya: khem or khera
•
Thai: pla loma hua bat
("alms-bowl dolphin", due to the shape of their head)
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| Size of Pesut Dolphin |
Behavior
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| Pesut Dolphin in Mahakam River |
• Irrawaddy dolphins communicate with clicks, creaks and
buzzes at a dominant frequency of about 60 kilohertz, which is thought to be
used for echolocation.
Bony fish and fish eggs, cephalopods,
and crustaceans are taken
as food. Observations of captive animals indicate food may be taken into the
mouth by suction. Irrawaddy dolphins sometimes spit streams of water, sometimes
while spyhopping, during
feeding, apparently to expel water ingested during fish capture or possibly to
herd fish. Some Irrawaddy dolphins kept in captivity have been trained to do
spyhopping on command. The Irrawaddy dolphin is a slow swimmer, but swimming
speeds of 20–25 km/hour were reported when dolphins were being chased in a
boat.
 |
| 2. kinds of food of Pesut Dolphin |
 |
| 1. kinds of food of Pesut Dolphin |
• It surfaces in a rolling fashion and lifts its tail
fluke clear of the water only for a deep dive. Deep dive times range from
70–150 seconds to 12 minutes.
 |
| 3. Kind of Pesut Dolphin food |
YEARS
|
POPULATIONS
|
DECREASE
|
PERCENTAGE
|
1975
|
1000
|
0
|
0.00
|
1980
|
800
|
200
|
21.05
|
1985
|
600
|
200
|
21.05
|
1990
|
400
|
200
|
21.05
|
1995
|
100
|
300
|
31.58
|
2000
|
50
|
50
|
5.26
|
2950
|
950
|
100.00
|
|
Source: BKSDA Kaltim: 2000
|
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From these data we can get the information that each range
years there has
been a very significant decrease. From the time span between 1975-2000 there is
a large decrease in the Irrawaddy 950 tail. Where there is a reduction from the
1975-1985 per 200 head or 21.05%. In 1980-1985 a decline in 200 tail or 21.05%.
Just as the span of a year earlier, in the range of 1985-1990 drop as many as
200 dolphins tail or 21.05%. While the range of 1990-1995 decreased dolphins
huge tail that is 300 or 31.58%. But the range of 1995-2000 decreased slightly
reduced Irrawaddy, 50 tails, or 5.26%. The decline in the number of dolphins population we get from year to year on these data, we can
conclude that the population of dolphins will be depleted if this still
happens.
Environmental
Impact on the Habitat of Dolphins
•
Forest damage
Forest vegetation is useful as many barriers to erosion
damage. So that when the rainy season arrives, the resulting erosion rates are
very high and result in siltation in the river as a habitat for dolphins. Sedimentation resulted in the silting of the river
dolphins are very significant areas of life. So that the dolphins are ideal
habitat to a depth of 9-12 meters are no longer ideal. This resulted in the
reduced population of Irrawaddy.
•
Decreased levels of oxygen in water
Oxygen is a substance that is vital for living beings.
Reduced oxygen levels result in decreased rate of metabolism of living beings
that ultimately can impact on mortality. The decrease in oxygen levels in the
water causes a decrease in populations of small fish which is the main source
of feed dolphins. Decreased levels of oxygen can be caused by several things
including industrial waste pollution by factories that discharge their waste
into the river Mahakam, household wastes such as detergents and booming exhaust
phytoplankton.
•
Siltation of rivers and lakes
The main cause of the silting of the lake is muddy
from Upper Mahakam River Basin. The results of the Public Works Department
analysis of 1993 East Kalimantan on the Mahakam river mud into the lake
physically can lead to siltation as thick as 10-12 cm / year. Damage to the
upstream sub watershed Mahakam caused by illegal logging, coal mining and oil
and plantation activities aggravate the deposition process in the Mahakam river.
This is especially devastating for the lives of dolphins because dolphins ideal
habitat for life on the river with a minimum depth of 9-12 meters.
•
Chemical pollution of the river
Contamination of chemicals such as mercury, DDT, coal
and so greatly affect the population of dolphins in the Mahakam river. In
addition to dolphins can be deadly, these chemicals can also lower levels of
immunity dolphins nature. Examples are coal pollution can change the skin
pigment dolphins and reduce the ability to adapt, so the impact on the population
of dolphins in the wild.
Decline in distribution and population decline
dolphins in the Mahakam River, can be overcome by.
It is necessary to the conservation area that
specifically protect the dolphins Mahakam. As a concrete step to protect
dolphins from extinction, which is integration, especially regarding the
maintenance and enhancement of fish populations feed dolphins, habitat improvement
and utilization settings.
Educate the public about habitat for dolphins in the
Mahakam to be more friendly with dolphins. Thus the resulting pollutions that can contaminate the habitat of dolphins Mahakam
more repressed existence.
Cessation of illegal logging
Forests are decimated by illegal logging will result in a lack of CO2 gas that
is synthesized back into oxygen gas. If carbon dioxide gas that is synthesized
and fewer still roam the earth without a controlled atmosphere, the carbon
dioxide gas will be trapped and cause the greenhouse effect.
Reforestation
As a further step the number of damaged forests, the reforestation are concrete
steps to rehabilitate the forest conditions that have been damaged.
Conclusion and Suggestion
- Area of deployment and the number of dolphins population continued to decline from year to year
- Environmental damage resulting changes and will impact back to the environment.
- The government to pay more attention to and care about dolphins habitat Mahakam is more real. One role that government should do is issue a law that protects dolphins Mahakam.
- To the communities surrounding habitats for Irrawaddy dolphins, and more concerned about protecting its existence.
- Strict law enforcement against violations primarily involving environmental damage.
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| Pesut Dolphin |
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