Net loss

Fishing practices in Chilika are threatening the Irrawaddy dolphin, which is not only rare but also little known

 
By R S Lal Mohan
Last Updated: Sunday 28 June 2015

-- (Credit: Rustam Vania)ORISSA'S Chilika lake is known for its natural splendour and beauty and the wealth of bird and marine life which it harbours. Recently, it has acquired additional prominence owing to the controversial prawn culture project initiated by big business houses, which the local marginal fishermen -- supported by the environmentalist lobby -- are opposing.

Among Chilika's myriad inhabitants is a species of rare dolphin -- the Orecella breviorostris -- also called the Irawaddy dolphin, which few people know about. In 1915, (Mr nnandale), the British naturalist and the former director of the Zoological Survey of India, first reported its presence in the lake and made some observations on the animal's food habits.

Chilika lake, being a lagoon with an area of 1,100 km, offers an ideal habitat for the species. Seawater is flushed into the lagoon during high tide, facilitating the entry of a variety of marine life through its deep and wide mouth facing the Bay of Bengal.

The dolphin of Chilika lake -- measuring about a metre at birth -- grows to a length of 3-4 m and weighs about 300 kg. It feeds on the smaller fish and prawns and matures at of 6-7 years. The distinguishing feature of the dolphin is its blunt snout. In most marine dolphins, the beak is elongated.

Local fishermen call the dolphin mugger mas (crocodile fish). At the mouth of the lake, there is a deep area known as the Mugger mukh. Usually, the dolphins prefer to romp around in this area as it is deep and has a good concentration of fish. Found in the middle of the lake during the rainy season, they confine themselves to its mouth during the dry season.

Available information about the Irawaddy dolphin is still sketchy, the animal being restricted to Southeast Asian countries like Myanmar, Malaysia, Thailand, and Vietnam. The iucn's Red Data Book lists the species under the category 'K', implying that it is an insufficiently known species. The practice of keeping these dolphins in captivity and training them was prevalent in dolphinariams in Malaysia. But this species lacks the popular feat-performing capacity of the Bottlenose or the common dolphin.

The primary threats to the existence of these harmless animals are the gillnets sunk in the lake by fishermen. More than 50 gillnets of 100-500 m lengths are used daily in the Chilika, exposing the dolphins to them on an almost daily basis. The dolphins try to take fish from the nets and get entangled in them; usually their flippers or the tail flukes get caught. Being mammals, they have to surface at least once every 5 minutes for breathing. If they are forced to remain underwater for more than 7-10 minutes, they drown.

The Irawaddy dolphin is also coveted by the local fishermen who kill it using hand-held harpoons and extract oil from it. The oil is reputed for its curative properties, particularly in cases of rheumatism and joint pains: 100 gram of oil costs about Rs 50 in fishing villages like Balugon, dotted around the lake. Ever year, 4-5 dolphins fall to the fishermens' harpoons. For a meagre population of about 20 dolphins, this mortality rate is extremely high.

The Irawaddy dolphin is included in Schedule I of the Indian Wildlife Act, 1972. According to this Act, anyone found guilty of killing or harming the dolphins can be punished with an imprisonment of 2 months or a fine of Rs 2,000, or both. It is also listed in Appendix II of CITES which regulates any international trade. Additionally, the species receives protection as its habitat is included in the Ramsar Convention.

While the tourism department of Orissa has chosen to highlight the presence of the birds and temples around Chilika, it makes no mention of this rare species. "Dolphin sighting tours" could have immense potential in attracting tourists. Such tours, besides creating awareness among the people, could prompt fishermen to protect the dolphins, since the friendly mammals' capacity to attract and enthrall tourists could be the source of considerable business for them.

R S Lal Mohan is with the Conservation of Nation Trust, Calicut

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