Besides polluted water from factories and encroachment on the mangrove forest, Don Hoi Lot - a vast mudflat area in Samut Songkhram which is a major habitat of the razor clam - now has a new threat created by those whose lives depend on the creatures.

Instead of following their ancestors and using a small stick coated with lime powder to slowly open the hole where the clam lives, a new generation of razor-clam collectors splashes the area with caustic soda. This makes the clams leap suddenly from their holes.

"Sticking lime powder into clam holes one by one is too slow for them. With caustic soda, they can collect many clams in a very short time," said Anant Najchareon, deputy president of Bang Jakreng Tambon Administration Organisation, one of three TAOs overseeing Don Hoi Lot.

Anant said his TAO and the provincial authorities were concerned about the new practice, which is not easy to stop.

Located on the mouth of Mae Klong River, Don Hoi Lot is fertile. Sediment from the river makes it a perfect environment for numerous kinds of shellfish. The razor clam (solen regularis) - or hoi lot in Thai - is one of the main species of the area and a major source of income for generations of people in nearby areas.

Looking at the surface of the mudflats, it is difficult to see the holes where the shells live, so collectors have to use their hands or sometimes their feet to hit the mud so the vibration reveals the holes. Then a stick coated with lime is jabbed into a hole, and a clam will jump out, irritated by the lime.

Shellfish collectors then pick up only those big enough to be sold to nearby restaurants, while the smaller ones are left on the mud to grow. Though this method is still used today, the present generation of shell collectors has developed the new method, which they believe better suits the "new generation" of razor clams.

"The clams now resist lime, so they do not come out of their holes so often after being jabbed. Caustic soda is much better because it is much stronger than lime and the clams come out immediately," said Anusorn Noisiri, a shell collector.

Anusorn, 33, said he had, however, stopped using caustic soda as it had been banned by provincial regulations.

Anusorn's claim was disputed by a leading marine biologist, Thorn Thamrongnawasawadi of Kasetsart University.

"These clams have not evolved to resist lime. It's simply because there are not many clams left. With caustic soda, the clams will be eradicated from the area very soon," he said.

Thorn is afraid that caustic soda will not only kill the present generation of clams, but also contaminate the mudflats so the next generation of razor clams is threatened too.

According to Anant, caustic soda was introduced to Don Hoi Lot two years ago after the people there learned the tactic from razor-clam collectors in Pak Nam, Samut Prakan, where people have never used the stick method.

Information from the Fishery Department suggests the number or razor clams in Pak Nam is falling, and the area where the clam can be found is shrinking. Anant is concerned the same phenomenon will occur at Don Hoi Lot if people do not stop the "devastating" new shellfish-collecting tactic.

Anant said collectors dissolve caustic soda in water which already includes lime. They then splash the water onto the mudflats and all razor clams in the splashed area then surface and are collected, regardless of size.

Two years ago, the Don Hoi Lot Protector Team was established by Bang Jakreng TAO to monitor the way the people collect the clams. Those who used caustic soda were arrested and fined.

Anant said it is not easy to control the clam-collecting in Don Hoi Lot because of its vast area, more than 15,000 rai. At low tide every day there are about 300-400 people collecting the clams.

The mudflats are part of the Don Hoi Lot wetland, which covers more than 500,000 rai. It has been declared a Ramsar site under the Ramsar Convention of Wetlands.

Razor-clam collecting is a very cheap and easy business. With an investment of less than Bt20 to buy lime and caustic soda, a collector can earn about Bt100-Bt300 a day, depending on how many clams are collected.

"People believe the clams at Don Hoi Lot will never become extinct and many of them do not care about the long-term effect of their collecting method," Anant said.

While clam collectors insist the use of caustic soda is decreasing because it also damages the health of the collectors, Anant insists the use is increasing because of the price the clams can fetch.

Anant said razor clams were in great demand in the market, where supply is always short. "The clam has a very high price, about Bt40-Bt60 per kilogram," he said.

Bang Jakreng TAO is now collaborating with the Samut Songkhram governor to look for a way to eradicate the use of caustic soda. Several tactics being discussed are market controls and a price guarantee.

"The TAO could be the only agency to buy the shellfish from the collectors with a guaranteed price, but collectors would have a limited quota. A system to test the shellfish might be set up so that all clams sold at the TAO would be checked for whether caustic soda had been used," Anant said.

"If caustic soda was used, when the clams are boiled the water has many bubbles and the TAO would not buy them."

Clam collector Anusorn does not think the price guarantee will work. "There are so many collectors, I don't think they would have enough money to subsidise them." However, Anusorn said he was willing to cooperate with any plan the TAO introduced to protect the mudflats.

Pennapa Hongthong

The Nation