A dead Giant Freshwater Stingray that floated from the Mae Klong River to Khlong Bang Khan Taek in Muang district, Samut Songkhram, found on Friday.
Photo: Pattarapong Chatpattarasill
Thailand: Alarm over dead Stingrays in Mae Klong River
By Ploenpete Atthakor, 7th October 2016;
The discovery of 14 dead Giant Freshwater Stingrays (Urogymnus polylepis) in the Mae Klong River in Samut Songkhram has sparked suspicions some factories have discharged polluted water into the western region’s major waterway.
Fourteen dead Stingrays, a threatened species, have been found floating in the river since Sept 29, prompting an inspection that found the water’s condition has deteriorated, with the biochemical oxygen demand (BOD) level now delow acceptable standards.
An investigation has been set up to find the cause.
An environmental protection group in Ratchaburi has filed a complaint against a Ban Pong-based sugar factory, believed to have discharged water into the Mae Klong River.
Rattawut Wallathanaroj, secretary-general of the network for environment protection and corruption, said provincial industrial authorities took samples of water from the factory’s outlet pipe to check for pollutants.
He said the river’s banks are dotted with large industrial plants, some of which may be in breach of environmental regulations.
“It must be investigated if water discharged from these Ratchaburi-based factories is linked to the death of the Stingrays,” said Mr Rattawut, adding he believed there is connection given the location of Samut Songkhram at the river’s end, that makes it a catchment area.
An official at the Ratchaburi Industrial Office said he was still waiting for the result of the tests on the discharge from the sugar factory.
“In fact, the factory does treat the water but regulations state it must store the water for use by farms, not release it into the river,” he said.
The Ratchaburi-based factory was a long way from where the Stingrays were found. At this stage it was not known if the factory was to blame.
“We are working with officials in Samut Songkhram to establish the cause,” said the official, who asked not to be named.
He said it was possible that, given Samut Songkhram’s normally saline water, a sharp rise in the freshwater level as a result of heavy rains in recent weeks may have caused the fish deaths.
“Fish can go into shock in such conditions,” he said.
However, Chavalit Vidthayanon, an ichthyologist, ruled out the suggestion a rise in freshwater levels may be the cause. He blamed it on water pollution from factories.
The Giant Freshwater Stingray is on the IUCN’s red list of threatened species and is highly sensitive to pollution, he said.
“If the freshwater level rises, it can swim to the river mouth and out to sea,” he said.