By Maung Tha (Archaeology)
Out of the myriad of aquatic animals that flourish in the water of the present world, only three species of warm-blooded mammals are found living in aquatic habitat. Those mammals are dolphin, whale and dugong all of which except one species of dolphin are found in sea water. (30) different species of dolphin are known so far and only one is found as fresh water species and its scientific name is Orcaella brevirostris. It is widely known as Ayeyawady Dolphin.
Sir Richard Owen recorded in 1866 about his discovery of Ayeyawady Dolphin species in 1852 near the harbor of Visakhapatnam on the eastern coast of India. An English naturalist, John Anderson had been to Myanmar and made a research exploration along Ayeyawady river from 1871 to 1879. During his research trip he discovered the round-snouted ash grey dolphin in Ayeyawady river and he became the first person who ever had discovered such type of fresh water dolphin. When he got back to London he wrote a research paper under the title “Description of a new cetacean from the Irrawaddy River, Burma” and submitted to London Zoological Association. He described those ash-grey dolphin as Ayeyawady Dolphin in his paper and henceforth it has been widely known as Ayeyawady Dolphin. The similar species found in other parts of the world are also referred to Ayeyawady Dolphin.
Myanmar and its Ayeyawady Dolphin
Professor H.G Luce of History Department, University of Rangoon wrote a research paper in Burma Research Association Journal with title “Ancient Pyu” in which Professor Luce mentioned that he found out the fact that the dolphin was discovered in Ayeyawady river and was then called “River Pig” in a record that had been written about Pyu. According to that record of Pyu era we can deduce the fact that the Ayeyawady dolphins have been inhabiting in the Ayeyawady river since the time of Pyu ie. more than 1000 years ago.
Apart from Myanmar waters, the species are also found in Chilka Lagoon near Orrisa State sea coast of India, Mahakan River of Indonesia Borneo Island, Songkla Lake of Thailand and Mekong River.
Though Anderson recorded his finding of Ayeyawady dolphin between Yenanchaung and Bhamo, Ayeyawady dolphins now occur only in the upstream of Mingun of Ayeyawady river. Myanmar Fisheries Department and Fauna Conservation Association has acted on the conservation of dolphins by dividing the 275 miles long part of Ayeyawady river between Mingun amd Bhamo into 6 segments as follows:
1. From Myazedi village upstream of Bhamo to Sinkhan
2. From Sinkhan to 2nd Defile near Shweku
3. From 2nd Defile to Tagaung
4. From Tagaung to Sanpanago
5. From Sanpanago to 3rd Defile of Kyauk Myaung
6. From Kyauk Myaung to Mingun
Out of those segments, the part between Kyauk Myaung and Mingun is the area most flourishing with Ayeyawady dolphins. 20 to 23 dolphins are usually found in this part of the river and 46.25 mile long segment 6 between Kyaumk Myaung and Mingun has been designated the main area for dolphin conservation.
Dolphins and fishermen
The dolphins thriving in the segment between Mingun and Kyauk Myaung are famous for having the very peculiar and interesting characteristics. The dolphins in this area demonstrate the enigmatic relationship with fishermen. They are supposed to assist the fishermen in finding the clusters of fish. The strange activities of dolphins are fascinating the people, both local and foreign and the dolphin lovers usually visit the place to watch the peculiarity of dolphins, thus forging a business in tourism like Dolphin Watching Tourism.
There are 10 villages between Kyauk Myaung and Mingun, fishermen from 7 villages are fishing with the help of the dolphins. It is so enthralling to watch the fishing with the help of dolphins that Dolphin watching Tourism will boom in near future.
A fishing boat is usually handled by two fishermen, one at the stern pedaling and steering the boat and the other throws the net into the water for catching the fish. The rower usually brings two oars, one short and another long one. Short one is used for propelling and the long one is used as punting pole for pushing the boat ahead in the very shallow part of the river where propelling by oar is impossible, by thrusting the long oar at the river bed and force the boat forward. The rower also brings a short wooden stick about one foot long with one end having about one inch in diameter and tapering to the other end.
The fishermen, when they are out fishing, try first to find the dolphins by inquiring the farmers working on the nearby bank and those working on sand bars in the middle of the river. Dolphins, being the warm blooded mammals, do not live long under water and often come up to the surface to breathe in the air. So people even on the distant bank can see the location of dolphins.
When the fishermen find the place of dolphins, they row their boat and approach the dolphins as nearly as possible and beat the side of the boat by the stick they bring rhythmically. Dolphins know the vibration produced by beating and they have sharp sensor to detect the location from where the vibration comes. Commonly two to three dolphins come to the fishing boat and stay at a reasonable distance.
A dolphin supposed to be the leader of the group surges its head above the water and then sets its tail vertically above the water. The formation of this type of display indicates the signal for the fishermen to be ready to catch the fish. When the dolphin exposing its tail horizontally above the water and slaps the surface of the water, the fishermen understand it is the signal to follow them. The fishermen then follow the dolphins which lead to the place where they can find the fish.
The strange relationship and understanding each other between the fishermen and the dolphin is quite interesting. The dolphins signal the fishermen to be ready for fishing by showing its tail straight up above the water as they see the cluster of fishes in the water below. When the fisherman at the bow of the boat, on seeing the signal from dolphins gets himself ready for fishing.
The leader having its tail straight up above the water and swimming in a semi-circle shape is actually trying to drive the fishes stay in group in a circle. The other dolphins are also swimming around the fish with intention to deter the fishes from straying away. Those activities of dolphins are known as “scaring fish”(ngar chauk) “assembling fish” (ngar su) and “showing for fishing” (kunchet pya). Those three separate terms are collectively called “Si Kho” by local people. The places of fishe presence shown by dolphins are commonly around the sandbars, in the channels between two large sandbars and in shallow parts of the river.
Once the fisherman saw the dolphin’s tail straight up above the water and swaying sideways, he throws the fishing net into the water. Dolphins never take the fishes caught in the net for food, they are just devouring fishes outside the net. It is quite amusing to see the natural rule exhibiting the sharing of food between the fishermen and dolphins. They help fishermen in finding the fish but never breach the nature’s law of sharing food.
The relationship between fishermen and dolphins is something like a joint venture practiced in human business. Combined effort of dolphins and human beings can make an appreciable volume of food that is shared between the partners according to the natural rule. The fishes in the net are for man and those outside the net are for dolphin. Another amazing thing about the astuteness of the dolphins can be seen in their nature that they never show the fish-flourishing place in deep water where most of the fishes are usually caught in the net and their share outside the net is remarkably reduced. They usually show the spot rich with fishes in shallow water where their shares are increased.
Conservation of dolphins
Average weight of Ayaywaddy dolphin is between 200 and 400 lbs. and it has 12 to 19 teeth. The body is measured to be long about 7 ft. and the girth is about 4 ft. A male dolphin found in Thailand measured 9 ft. in length. Life span is about 30 years and can do reproduction at the age of 7 to 9 years. Conception period is 14 months and usually give birth a single baby. Dolphin can swim 12 to 14 miles an hour and hear the sound with vibration wave 60KHz.
The population of dolphin in the world is reduced to 7000 and they occur only in Myanmar, Thailand, the Philippines, Indonesia, Laos, Cambodia, India and Bangladesh. Every country is now striving to conserve the dolphins and Myanmar is also doing its best to conserve the dolphins by monitoring, controlling and detering the catching, catching by electric shock and killing of dolphins.
In 2007 and 2008 NHK of Japan and German television and news media came to Myanmar and made television documentary on the life of dolphins and their activities in connection with finding the fish-thriving spot for the fishermen. The documentary was shown in their countries and Myanmar Ayeyawady dolphins could have attained worldwide interest and attention. The tourists taking riverine trip along the Ayeyawady river take television or photo records of the Ayeyawady dolphins. Dolphin lovers are also visiting Myanmar to watch the activities of dolphins in support of the fishing of local fishermen.
Despite high growth of population in the past, the Ayeyawady dolphin population is dwindling and only 70 dolphins were counted by the survey in 2014. Local people should have more awareness for the conservation of dolphins whereas the institutions concerned are now taking measures to prevent dolphins from extinction.—Translated by Khin Maung Win