Description
The Indus River dolphin
whose scientific name is Platanista minor is a freshwater cetacean
closely related to the Ganges River dolphin (Platanista gangetica).
The Indus
dolphins are mammals, not fish, although they live their entire lives
in the water, they breath air. These dolphin can hold their breath,
but must come up to breath air.Platanista minor
occurs only in the Indus River system, while Platanista gangetica
inhabits only the Ganges River system. The species is characterized
by a long beak, rounded belly, stocky body, very small dorsal fin and
large flippers. Although its eye hasn't developed a lens (this
species is also referred to as the "blind dolphin"), the
dolphin still uses its eyes to differentiate between light and dark.
It relies on echolocation (sound sensors) to find fish, shrimp, and
other prey in the bottom mud.
Indus
River Dolphins
- Length – 7 ft – 8 ft
- Weight – 150 lbs – 200 lbs
- Height – 8 ft to 10 ft at the shoulder
- Life Span – 20 to 30 years
- Color – Gray with White or Pinkish underside
- Eyes – Functionally Blind, has no lens
Population
Numbers
The
Indus River Dolphins population is estimated at 1,100. Indus River
dolphins become sexually mature at lengths of about 5.5 ft or more
and begin breeding between 6-10 years of age. Females give birth to a
single calf that is about 2-3 ft long. The gestation period of the
female is 10 months. The babies stay close to their mother for the
first six months of the life. The mothers may also nurse calves for
about 1 year before weaning.
Habitat
and Range
Indus
River dolphins prefer the fresh and possibly brackish, shallow
(usually less than 100 ft), murky waters of the Indus River in
Pakistan. Their current range is about 435-620 miles along the Indus
River and its tributaries. Their migrations have been linked to the
monsoon. Historically, their range extended from the Indus River
delta to the shallow, rocky foothills of the Himalayas (2,100 miles).
The tributaries they once occupied include: the Sutlej, Ravi, Chenab,
and Jhelum Rivers. Today, their distribution and range is extremely
limited; it is currently just 20% of its historical extent.
Cause
of Decline
The
main reason for the decline of the Indus River dolphin was the
construction of numerous dams and barrages. These split the
population into small groups, degraded habitat and impeded migration.
Accidental capture in fishing nets and hunting for meat, oil and
traditional medicine have also had an adverse impact.
The resulting habitat fragmentation has lead to strandings of the species in irrigation canals. These stranding usually go unreported, and as a result, individuals are left to die. Dolphins are no longer found in the lower parts of the Indus due to water extraction which dries-up downstream channels for several months each year.
Another cause of the decline of the
Indus River dolphin is bycatch, which is the accidental catch of
these dolphins. Because fishing nets are set for extended hours,
including overnight, dolphins sometimes get trapped and drown.
Finally, pollution is also suspected of killing the Indus River dolphins.
Important
– Why Indus Dolphins Matter
Dolphins play an important role in the ecosystem, helping
maintain a healthy balance. Without dolphins, their prey would
increase in number, and their predators wouldn’t have as much food
to eat. This would disrupt the natural balance in the food chain, and
could have a cascading effect – negatively impacting other
wildlife, and damaging the health of habitats and ecosystems.
Dolphins are a key indicator of the health of their environment
because they are high up in the food chain. If there wasn’t a
healthy habitat with lots of fish for them to eat then the dolphins
wouldn’t be able to survive there. By protecting dolphins we’re helping preserve healthy marine habitats – which a large number of the world’s people heavily rely on for their livelihoods and food.
Conservation
Efforts
The
Indus River Dolphin is legally protected throughout its range and is
listed in the CITES. Two sanctuaries, the Taunsa Wildlife Sanctuary
(est. 1983) and the Chashma Wildlife Sanctuary (est. 1984) in Punjab
Province also appear to be helping to address the rapid population
declines. A program sponsored by the United Nations Development
Program (UNDP) to rescue dolphins trapped in irrigation canals and
return them to the Indus mainstream has had some success in reducing
mortality.Also being address is the problem with pollution in the river; WWF staff have also been involved in rescue missions when individual dolphins become trapped in canals. WWF-Pakistan assists in a number of education initiatives and has arranged training courses for various institutions.
The average person can help tremendously by reporting any dolphins that they may see trapped in the dams and canals, which is one of the major issue for the Indus River Dolphins.
Works
Cited
