Now the State Forest and Wildlife Conservation Department is carrying out a census of dolphins in the Bay of Bengal. Such operations are going on by the executive staff members of the department, particularly within the sites where dolphins are usually sighted.
When a census of animals or birds is conducted, their habitat and biotic field characteristics are taken into account which helps in accurate result. The dolphin is a sea mammal which prefers to live in shallow water of bay and sea gulf of the tropical and temperate climate.
This is a very ancient animal of the Indian Ocean. The dolphins are never seen single unless some adverse situations are faced by them. It is usually seen in groups. Dolphin is the fastest oceanic animal, which is capable of covering over 30 knots per hour. Each knot is equivalent to 1.85 nautical km.
The curious behavior of the animal always helps for enumeration of the spices. Dolphin produces numerous underwater sounds as means of communication among them. There is strong cooperation between the members of a group.
The injured and disabled are always helped by the group as an eco-gesture. Commonly, the animal eats fishes and the species generally lives in ocean floor. The distinctive feature of the species is that it has a prolonged snout like a long narrow beak.
Both jaws contain numerous small teeth which exceeds 35 in number in each row. Both pectoral and dorsal fins are found in its body which is slender and there is no hair in the body. The colour of dolphin is white. There are fulvous or ochre bonds in both sides of under parts.
Similarly, a ring of black circle is noticed in each eye. Dolphin is found from Sri lanka sea to the Sundarbanas and even in Arbian sea-coast. Dolphins are dancing dainties which are intelligent and friendly to man. They are highly social creatures. The general foods of dolphins are fishes, molluses and crustaceans.
The bow waves of boats generally attract the playful dolphins in the sea, which sometimes cause accidents and take their life. Dolphins sometimes dive deep to 200 meters in the sea for catching fishes and came back again to surface of water to breathe fresh air. They locate their prey in the dark through a sound- radar system which is quite unique in the animal world.
The Gangetic dolphins are found in river Ganga, Brahmaputra, and Indus and even in the larger tributaries of these rivers. These species are always seen in the tidal limits of the ocean and gulfs, but they do not enter into deep sea. The Gangetic dolphins are non gregarious as compared to common dolphins and always found in small groups in search of food. The Gangetic dolphins always enter into rivers for a short period during flood and rainy season.
A few years ago, two dolphins of Gangetic type had migrated into Budhabalang river of Similipal hill region during flood months. During monsoon months, the Gangetic dolphins descend to tidal regions of the sea for hunting and usually are caught in the fisherman’s nets.
The breeding season of dolphin is usually after winter and usually one or two youngs are born between April and July. The period of gestation is about eight to nine months. The dolphin is hunted for meat. Oil is prepared out of its flesh. The oil is used for preparation of several medicines.
Now, the census of dolphin is being undertaken by the Chilika Development Authority in collaboration with the Forest department. Six teams have been deputed in Barkul, Balugoan, Tangi, Satpada, Krishnaprasad, and Nuapada for the census of the animals.
Environmentalists and experts on dolphin have joined the operations. Chillika itself is a dolphin hub where round the year the mammal is sighted. In Odisha coast, five types of dolphins are found such as irrawady — dolphin, bottle nose, finless perpoise, hump back and Gangetic dolphin. As observed like the population tiger, the population of dolphin is also on a declining trend.
The main reason is destruction of habitat and reduction of habits. The habitat is polluted day by day for human pressure and poisoning for cultivation of prawns. Application of chemical fertilizers and pesticide and dwindling of the population of crustaceans and cat fishes are the causes.
During last census in 2011-12, the population of dolphin in Chilika region was 145 while it was 161 in 2009-10 and 156 in 2010-11. In Astarang region, the dolphin sites are Devi mouth, Chandrabhaga, Arakhkud, Keluni –Mahan, the stretches right from Astarang to Chandrabhaga.
Dolphins are also sighted in Bhitarkanika wetlands, which is a new trend. As reported in Bhitarkanika wetland, six varieties of dolphins are found. A research work on irrawaddy dolphin is going on in Chillika since 1997. The entire sea coast of Odisha covers 400 km right from Bengal border, Digha to Andhra- border, Gopalpur. The sea coast also covers various river mouths, estuaries and creeks.
(The writer is a former senior forest officer and an environmentalist. Tel no 9937460649)