A latest census report of these aquatic species released yesterday by state Forest department showed there were 55 Irrawaddy dolphins in the water-bodies of Bhitarkanika and Gahirmatha.
Though it is been marginal drop from 2015 but officials say that since the sea was rough during the headcount, the actual number may be on the higher side.
The census conducted in the year 2015 had accounted for 58 Irrawaddy dolphins living in these water bodies, said forest officials.
Besides Irrawaddy dolphins, 27 Humpback and Pantropical spotted dolphin species were sighted during the one-day head count of these aquatic animals last month.
Irrawaddy dolphin (Orcaella brevirostris) is a highly endangered species. Total population of these animals in the world is estimated to be less than 7,500 with highest being little over 6,000 reported from Bangladesh. The population of Irrawaddy dolphins in Chilika is considered to be the highest single lagoon population with recorded head count of 121 this year, said forest officials.
During the 2015 census, 270 dolphins had been spotted.
Last year, the census operation had been suspended due to rough and adverse sea condition.
This year also, the rough sea had played spoilsport affecting the hassle-free head count drive. Though only 82 species including 55 Irrawaddy dolphins were spotted this year, the actual number may be on the higher side, Divisional Forest Officer, Rajnagar Mangrove (wildlife) Forest Division, Bimal Prasana Acharya.
As the marine sanctuary is largely free from human interference, these marine animals might be finding it to be an ideal habitat.
A status survey of these marine animals is vital for the study of growth pattern of species living within brackish water bodies and shallow sea waters of Bhitarkanika national park Ramsar international wetland site, said forest officials.
As the sighting of dolphins has become a routine feature for wildlife personnel during turtle patrolling duty, the forest department a couple of years back had decided to conduct census of these mammals.
Every year the forest department conducts annual head count of estuarine crocodiles, winter migrant avian species, monsoon migrant water birds.
A count is also done for Olive Ridley turtles engaged in annual mass nesting at Gahirmatha beach. Besides the head count of mammals such as monkeys, hyenas, jackals and fishing cats was carried out last year.