Are the Irrawaddy dolphins in Burma holding steady or are they headed for extinction?
In Burma, Irrawaddy dolphins have generally been revered by local people in addition to providing direct economic benefits to cast-net fishermen through their role in a human-dolphin cooperative fishery. As with other dolphins who live in such close proximity to humans there are several threats to their survival however, in Burma there is concern that one threat in particular is on the increase with potentially devastating effects – the extirpation of the Irrawaddy dolphin from the very river that they were named after.
Electric fishing, cited as being responsible for the largest number of known deaths of the now functionally extinct baiji, has been a problem along the Ayeyarwady River for many years however in recent years the magnitude of this problem has increased substantially. Other threats include entanglement in gill-nets, chemical and noise pollution from mercury and blasting both used in nearby gold-mining processes and habitat modification as a result of increased sedimentation also from nearby gold-mining processes.
Between 2002 and 2004, WDC in collaboration with WCS and the Burmese Department of Fisheries (DoF), conducted surveys to determine the range and abundance of the species in the river. Results showed that the range of the dolphins had declined dramatically (by over 50%) compared with historical reports and the population was estimated to be between 59 – 72 individuals. This information along with other information on the growing threats to the dolphins resulted in the population being classified as Critically Endangered (CE) – a classification given to all populations of Irrawaddy dolphins found outside of India and Bangladesh.
As a result of this, in December 2005 the DoF created a protected area for the dolphins in a 74-km river segment which included requirements for fishermen to immediately release dolphins if they were found alive and entangled in their nets, prohibited the catching or killing of dolphins and trade in whole animals or their body parts, banned the use of gill-nets that obstructed the water-course and reiterated the ban on electric fishing.
Recent surveys undertaken by the DoF put the population of Irrawaddy dolphins in the Ayeyarwady River at 63 individuals. This number sounds low (hence their status as CE) however, given that the population estimate from 10 years ago was 59 – 72 individuals perhaps the Irrawaddy dolphin is managing to hold on in the face of extreme adversity.
The real decline seems to be in the number of dolphins fishing co-operatively with the local fishermen. They believe that this is due to the fact that the noise they make to attract the dolphins is the same as the noise emitted from electric fishing operations and the dolphins are just scared of getting trapped and killed by those fishermen engaging in the illegal practice. In Burma therefore, although the friendship and mutually benefical relationship between man and dolphin may be falling apart it looks as if the population numbers are holding steady. The sad truth is that perhaps the only way for them to survive in the long term is to distance themselves from mankind even further.
Watch this report from the BBC investigating the decline of Irrawaddy dolphins.