'The dolphins killed by fishing nets can be easily identified because of the wounds on the their bodies," Santi Ninwat says.
CASUALTY OF CARELESSNESS: Left, the carcass of an Irrawaddy dolphin is recovered from Songkhla Lake after it became trapped in a fisherman’s net.
A marine biologist at the Southern Marine and Coastal Resources Research Centre, Mr Santi has been studying the Irrawaddy dolphin population in Songkhla Lake since 2007.
His findings are alarming.
With the lake's dolphin population now on the brink of extinction, he says overfishing and development are contributing to their ongoing demise.
"Some of the dead dolphins are found without a tail. Fishermen had cut their tails off to avoid them damaging their nets," he said.
"Also, some carcasses were torn into pieces in order to eradicate evidence, because it could a create public outcry.
"Many carcasses were too decomposed to find any evidence, particularly the young ones."
Since 2007, some 66 of the lake's dolphins have been found dead _ 12 have died this year alone.
The situation has marine scientists and local conservation groups worried. They estimate that only about 20 or 30 of the threatened dolphins are left in the lake. With an average of 10 deaths per year, and females giving birth to just a single calf every two or three years, the situation looks dire.
Irrawaddy dolphins can be found in both freshwater lakes and rivers as well as near coastal areas in South and Southeast Asia.
But freshwater populations of the marine mammal are rare, found only in five places worldwide: Songkhla Lake; Myanmar's Irrawaddy river, from which the dolphin takes its name; Mahakham river in Indonesia; Chilka Lake in India; and a section of the Mekong river in Cambodia and Laos.
The dolphin is listed in Appendix I of the Convention on International Trade in Endangered Species of Fauna and Flora (Cites), which forbids all commercial trade in species which are threatened with extinction.
MOUNTING TOLL: Right, officials from the Marine and Coastal Research Centre in Songkhla province inspect the carcass of a young Irrawaddy dolphin to try to determine the cause of death.
A small Irrawaddy dolphin population can be found in the central area of the upper part of Songkhla Lake, which is located in the provinces of Songkhla and Phatthalung.
In the past, the dolphins were believed to have been able to swim through canals which linked the lake to the adjacent Gulf of Thailand. But due to the construction of sluice gates and dykes, and major fishing activity in the area, they can no longer travel to the coast and have been forced to adapt to their new, confined, environment.
Research conducted by the Marine and Natural Resources Department found that the dolphins now live and hunt in the same area where fisherman cast long nets to catch giant catfish that were released into the lake about two decades ago.
"We don't know how many giant catfish are in the lake, but the Fisheries Department a few years ago agreed not to release any more. They are not a native species in the lake, and they cannot breed naturally in the lake environment," said Somchai Man-anansap, director of the Marine and Coastal Resources Research Centre for the Lower Gulf of Thailand.
About 20 local fishermen cast their nets in search of the giant catfish, whose population started to boom in 2008. They use large-hole nets suitable for big fish, with the nets sometimes reaching as long as three kilometres. Sometimes, they catch dolphins too.
CAUSE OF DEATH
The reasons behind the decline of Songkhla Lake's Irrawaddy dolphins are more complicated than fishing alone.
In past years, most of the deaths have been attributed to the giant catfish nets.
According to Mr Santi's research on the lake's dolphins from 2007 to 2009, 35% of the 24 recorded dolphin deaths in that time were caused by fishing nets, 15% were caused by unknown fishing equipment, and 10% from disease. The cause of death for the other 40% could not be determined.
To solve the net problem, the Southern Marine and Coastal Resources Research Centre and other government agencies have placed buoys to mark off the area where the dolphins live and hunt.
"It is about 100 square kilometres. Still, we have found fishing nets in that area, leading to more dolphin deaths," Mr Santi said.
Authorities have also conducted campaigns to discuss the issue with local fishermen over the past few years, some of which have been fruitful.
"We received more reports on the dead ones, and also received information on the whereabouts of the living ones [after speaking to fishermen]," Mr Santi said.
This year, he said none of the 12 dolphin deaths could be conclusively blamed on fishing nets.
"One possible reason for that is that the campaign for fishermen to stop catching giant catfish with large nets has been successful in certain parts of Songkhla," he said, adding that authorities are also working to persuade fishermen in Phatthalung province to follow suit.
"Twenty fishermen seems a small number. But each one owns so many huge fishing nets," he added.
If none of the deaths this year were caused by fishermen, however, it leaves unanswered questions about what exactly is driving the decline in the population. The disproportionate loss of young calves is a particularly worrying trend, with Mr Santi pointing out that among the dead dolphins, some 50% were juveniles.
"The loss poses serious problems to future reproduction," he said.
One theory about the deaths of the young involves inbreeding, caused by the already dwindled population.
"Inbreeding can result in physical defects and genetic problems. At the same time, it reduces the gene pool. With a small and isolated population, this will be critical to the survival of the species in Songkhla Lake," Mr Santi said.
The centre has yet to conduct a comprehensive study into the genetic problem plaguing the group.
Mr Santi believes deteriorating water quality in the lake is also harming the dolphins. The lake is surrounded by rice fields and plantations that make heavy use of chemical fertilisers and pesticides. The water has become polluted from chemical run-off and wastewater, he said. "We also have a problem with soil erosion and sediment [from nearby farmland running into the lake] which has made the lake shallower. This reduces food sources for the dolphins," Mr Santi said.
TOO LITTLE, TOO LATE?
Early this month, several government agencies signed an agreement to cooperate on a project to save the Irrawaddy dolphins in Songkhla Lake. Mingkhwan Tornsirikul, of the Office of Natural Resources and Environmental Policy and Planning, which is part of the Natural Resources and Environment Ministry, said the one-year project, starting next fiscal year, will see provincial authorities from Phatthalung and Songkhla take responsibility for eradicating the use of giant catfish nets in the area where the dolphins reside.
Legal measures will be put in place to enforce penalties against those using fishing gear which is harmful to the dolphins.
"Improving the fertility of the dolphins' food sources is another important method to prevent them from being forced into other areas," Ms Mingkhwan said.
Mr Santi agreed. "From December to January, the dolphins find food in outer areas of the lake. It is dangerous for them. With enough food, they would not have to travel far and get trapped in the fishing nets," he said.
"At the same time, if the dolphins can remain in a more confined area, it makes it easier for us to protect them.".
GETTING ON BOARD
Uthai Yodchan, 59, a local fisherman and chairman of the Irrawaddy Dolphin Conservation Club of Ban Laem Had, said five Songkhla fishermen who catch the giant catfish have already pulled their nets out from the lake in response to the dolphin issue.
"But another 15 fishermen in Phatthalung do not want to give up. We are very worried," he said.
Mr Uthai and other locals founded the conservation group seven years ago after they helped officials survey the dolphin population in the lake. His group has urged provincial agencies to help protect the species and to conduct campaigns for local fishermen to stop them endangering the dolphins.
"I always go to observe the dolphins in the lake. I think there are only about 20 left. We do not want to lose more," he said.
Mr Uthai said the dolphins were currently searching for food on the Phatthalung side of the lake, where fishermen continue trawling for giant catfish. Did that mean more deaths were likely? "Probably," he said.
About the author
- Writer: Tunya Sukpanich