Bhubaneswar, Feb. 27( Odisha.in ) Population of Irrawadi Dolphins which is one of the rare species and has been declared as an endangered species, have recorded a slow rise in Chilika lake located at a distance of about 110 kms from Bhubaneswar.
While according to 2007 census the number of this species was recorded at 133 during the latest census completed on 26th February, 2008 ( Tuesday ) the number has been recroded at 138 , which is a rise of only 5 above the last census. However during this period there has been casulty of 5 Irrawadi Dolphins in this lake.
The census was carried by Chilika Dvelopment Authority along with scientists from Japan University Tokyo, Indian Institute of Technology, New Delhi, Natural History Soceity, Mumbai, World Wildlife Fund and few other organisations on Monday and Tuesday. Local fishermen were also associated in the census.
Dr. Sudarshan Panda, Chief Executive, Chilika Development Authority organised and co-ordinated the census.
Total number of 18 teams participated in the census. The census was carried on head count as well as by using hydrophonic systems recording the sound was of the dolphins.
This species has a large melon and a blunt, rounded head. Its beak is indistinct. The dorsal fin is short, blunt and triangular. It is located about two-thirds of the way along the back. The flippers are long and broad. It is lightly colored all over – slightly more white on the underside than the back.
Length is about 1 m at birth and 2.3 m at full maturity. Birth weight is about 10 kg. Adult weight exceeds 130 kg. Lifespan is about 30 years.
The Irrawaddy Dolphin is a slow swimmer. It surfaces in a rolling fashion and lifts its tail fluke clear of the water for a deep dive only. Irrawaddy Dolphins spit streams of water from their mouths while spyhopping. Dolphins of the species kept in captivity have been trained to do this on demand.
The Irrawaddy Dolphin was identified by Sir Richard Owen in 1866 and is one of two species in its genus.
On account of their coastal nature Irrawaddy Dolphins are more susceptible to interference than other river dolphins.
The most direct threat is the capturing of Irrawaddys for their oil. As an endangered species, they are legally protected from hunting; however, enforcement may be poor along tens of thousands of miles of coast line. Entanglements in gillnets and deaths injury due to explosives used in fishing are common .
All along its distribution population and other habitat degradation worries conservationists. Human influence such as nets crossing river channels restrict movement and isolate populations, causing them to decline.
However increase of population of this species in Chilka lake have come as a sigh of relief for the conservationists.