The Ganges River indus dolphin Platanista Gangetica Gangetica and Indus River Dolphin Platanista Gangetica minor are two sub species of freshwater or river dolphins found in the Indian sub continent. From the 1970s they had commonly been regarded as separate species. However in 1998, a seminal work on cetacean taxonomy listed them as a single species once again see taxonomy below. The single species is likely to have either the Ganges and Indus River Dolphin or Indian River Dolphin as its common name, although neither has yet spread into wide usage and the latter does not reflect that the Indus subspecies is resident primarily in Pakistan.
Until the 1970s the Indus and Ganges River Dolphins were regarded as a single species, first named by Roxburgh in 1801. However at that time it became clear that two populations, one centered on the Ganges River in India and the other in the Indus River in Pakistan had not interbred for many hundreds of years. Based on differences in skull structure, scientists declared the two populations as separate species. However Rice, in his taxonomic classification of cetaceans that has become standard in the field, found that there were insufficient morphological differences to warrant distinction at the species level. Thus just one species is recognised in the genus Platanista and four true river dolphin species, each in its own family as well as genus.
The Ganges and Indus River Dolphins are essentially identical in appearance. They have the long, pointed snout characteristic of all river dolphins. Both the upper and lower jaw sets of teeth are visible even when the mouth is closed. The snout thickens towards its end. The species does not have crystalline eye lens, rendering it effectively blind, although it may still be able to detect the intensity and direction of light. Navigation and the hunt for food is carried out using echo location. The body is a brownish colour and stocky at the middle. The species has only a small triangular lump in the place of a dorsal fin. The flippers and tail are thin and large in relation to the body size, which is about 22.2m in males and 2.4 2.6m in females. The life span and other life history data is unknown. The species feeds on shrimp and small fish that prefer the waters close to the river bed. Dolphins are usually encountered on their own but have traveled in groups more often historically, when populations were larger.
Population and distribution
The Ganges subspecies can be found in the Ganges River as well as the Brahmaputra, Meghna, Karnaphuli and Sangu river systems of India, Bangladesh, Nepal and Bhutan. Relatively high population densities have been observed near the Vikramshila Gangetic Dolphin Sanctuary in Indian and in the Sangu River in southern Bangladesh. Very few individuals perhaps 20 are present in Nepal in the Karnali River. The total population is unknown, but certainly numbers in the hundreds and there are perhaps as many as a few thousand but see Human interaction below. The Indus subspecies resides primarily in the Indus River in Pakistan. In the nineteenth century its range was approximately five times greater than it is today, and included the Sutlej, Ravi, Chenab and Jhelum tributaries of the Indus. The highest population density occurs in Sindh Province. A comprehensive population census of the Indus Dolphin that was completed in 2001 by WWF Pakistan concluded that there are approximately 1,100 individuals alive today.
Both species have been very adversely affected by the use by humans of the river systems in the sub continent. Entanglement in fishing nets can cause significant damage to local population numbers. Some individuals are still taken each year and their oil and meat used as a liniment, as an aphrodisiac and as bait for catfish. Irrigation has lowered water levels throughout both subspecies ranges. Poisoning of the water supply from industrial and agricultural chemicals may have also contributed to population decline. Perhaps the most significant issue is the building of more than 50 dams along many rivers, causing the segregation of populations and a narrowed gene pool in which dolphins can breed. There are currently three sub populations of Indus Dolphins considered capable of long-term survival if protected.
Indus dolphin rescue drive from 15th
KARACHI: A five day operation for the rescue of the blind Indus dolphin Platanista minor, one of the worlds most threatened species of freshwater dolphin, will begin on Jan. 15, sources in the Sindh Wildlife Department, which will conduct the operation, told Daily Times on Thursday. The operation, which will continue until Jan. 20, will be in collaboration with the Lahore Zoo and United Nations Development Program UNDP. The sources said that between August and December, the department spotted 33 dolphin stranded in the canals of the Sukkur and Guddu Barrages in Sindh. So far, nine of them have been rescued. Seven of the stranded cetaceans are as young as one or two years, the sources said. It is for the first time that so many stranded dolphins have been spotted in canals, the majority of them calves, the sources added. The sources said shortage of water and food and the current repair work on the Sukkur Barrage were the main reasons for the stranding of the aquatic mammals, which belong to the family Delphinidae and are related to the tooth whales. The Blind Indus Dolphin Rescue a $50,000 UNDP fund, is helping the Sindh Wildlife Department to rescue the endangered species, the sources said. Many Indus dolphins slip into canals from the river during flood seasons, or at the time of the opening of barrage gates, and become stranded. The stranded animals are put in large tubs to be transported back to the river, the sources said. Unlike the large marine species of the dolphin, the Indus dolphins are only five to six feet long. The sources said conservationists from Pakistan and abroad have been invited by the department to oversee the rescue operation. Among the foreign invitees is French
Indus Blind Dolphin Names
|Local Name:||Bhulan ( SINDHI & URDU )|
|Both subspecies:||Blind River Dolphin, Side swimming Dolphin, Susu|
|Ganges subspecies:||Gangetic Dolphin, Ganges Susu|
|Indus subspecies:||Bhulan, Indus Dolphin,Indus Susu|
|Class||Mammalia , Eutheria|
|Platanista gangetica gangetica|
|Platanista gangetica minor|