Dwarf or Mangrove Whipray (Himantura walga)
Sungei Buloh Wetland Reserve, 17th March 2016

This photo of a Stingray on a railing was shared by Noeleen Tan.

This is possibly the Dwarf or Mangrove Whipray, a species that is commonly found in inshore waters, as well as mangroves and river estuaries, although there are other species of Stingray found in the region that might look superficially similar.

Find out how you can contribute to Monday Morgue too.

• Wild Fact Sheets
• A Guide to Common Marine Fishes of Singapore
• The Tide Chaser: Cartilaginous Fishes (Phylum Chordata: Class Chondrichthyes) of Singapore
• Handlinefishing.com
• Sharks and Rays of Borneo
• Fishes of Andaman Sea
• Length-weight relationship of stingrays in Kuala Selangor, Malaysia
• Exploited but unevaluated: DNA Barcoding reveals skates and stingrays (Chordata, Chondrichthyes) species landed in the Indonesian fish market
• Species and size composition and reproductive biology of rays (Chondrichthyes: Batiodea) caught in target and non-target fisheries in eastern Indonesia
• Shark-References
• FishBase
• IUCN Red List

Photo: Pattarapong Chatpattarasill, in Bangkok Post

Thailand: 70 Car-Size Stingrays Die Mysteriously
The huge freshwater fish may have been killed by pollution in Thailand’s Mae Klong River.
By Brian Clark Howard, 10th November 2016;

More than 70 Giant Freshwater Stingrays (Urogymnus polylepis)—some of them nearly as large as cars—have been found dead in Thailand’s Mae Klong River over the past few weeks, according to National Geographic explorer Zeb Hogan, who is currently in the country studying the fish.

The die-off is alarming because so few of the river giants remain. Giant Freshwater Rays are listed as endangered by the International Union for the Conservation of Nature, and scientists say they need to learn more about their populations and biology.

Thai officials are currently studying the dead Rays with the goal of figuring out what killed them. They have reported that the river is slightly more acidic than typical around where the dead Rays were found, though it’s unclear if that is related yet.

Some Thai environmentalists have suspected a recent spill from an ethanol plant could have poisoned the Rays. Others believe they may have been poisoned by cyanide, possibly intended to kill other more desirable fish.

Freshwater Rays are rarely targeted directly by fishermen because they are not considered good to eat. They are also so large and strong that they tend to break most fishing gear.

A Ray recently found alive in the Mae Klong River was 7.9 feet across and 14 feet long and weighed an estimated 700 to 800 pounds, says Hogan, a professor of biology at the University of Nevada, Reno, and the host of the series Monster Fish on Nat Geo Wild.

Even though they’re not hunted, the Rays are occasionally entangled and killed as bycatch. They are also threatened by pollution, oil spills, and dams that have fragmented their habitat.

“One thing is clear: a reduction of pollution from surrounding factories is needed to improve the health of the river and save the Stingrays in the long term,” Hogan says.

Freshwater megafish, along with freshwater marine mammals, are among the most threatened species in the world, Hogan notes, thanks to pollution, overfishing, and heavy human activity along rivers, from shipping to dams.

“I am hoping that international coverage will encourage more measures to protect this incredible fish,” Hogan adds.

Source: National Geographic

Photo: Pattarapong Chatpattarasill, in Bangkok Post

Thailand: Enforcement needs sting to save the Rays
23rd October 2016;

After a preliminary examination showed that the spate of deaths of endangered Giant Stingrays (Urogymnus polylepis) was most likely linked to poisonous discharge from an ethanol factory, the relevant state agencies must now take action against the alleged polluter and work to prevent the problem from being repeated.

On Friday, the Pollution Control Department said the department presumed the death of the Stingrays was a result of high levels of ammonia from waste discharged from Rajburi Ethanol in late September.

The river led the discharged waste to Samut Songkhram which affected natural habitats in early October, causing hazardous effects. A number of Stingrays, along with other fish, were subsequently found dead in the Mae Klong River.

The incident shows environmental issues cannot be treated as isolated cases because they can affect all of us. Natural resources such as air and water are shared by everyone. Pollution in one location can be harmful to inhabitants on a much larger scale, as was the case here. The case cannot be dismissed or ignored simply because there have been no human casualties.

After the preliminary findings, the department said it plans to take legal action against the alleged polluter.

Let’s just hope the incident isn’t swept away from the spotlight any time soon. The case has to be pursued vigorously to set an example for other factories sprouting up as part of Thailand’s quest for industrial growth.

The death of the Stingrays is only the tip of the iceberg. It exposes the bigger issue of insufficient control over waste discharge from factories. Public waterways should be preserved because they serve as the community’s bloodline, an essential part of the agriculture-based society in Thailand.

The case also shows people’s inability to balance economic development with environmental health. Industrial development does not necessarily come at the expense of nature but, as is the case here, it happens too often.

There is an old saying that goes: “In Thailand, there is rice in the field and fish in the river.” Unfortunately, in this case instead of living fish, there are high amounts of ammonia waste in Thailand’s rivers.

Regardless of what the industries may say, the incident shows they have not done enough to prevent it.

Even without this case, people have been unkind to nature far too long. Freshwater Stingrays have been rapidly declining in Thailand.

Stingrays can grow to two metres in length and can weigh as much as 600kg. The global population of Giant Freshwater Stingrays has declined between 60-80% in the past 30 years. Their habitats range from rivers in the Central region of Thailand, to the Mekong Delta and Borneo.

Thailand has lost 90% of its Freshwater Stingray population in those three decades. It would be shameful if we failed to preserve one of the world’s largest cartilaginous fish.

There is now a 90% chance that the fish will become extinct in Thailand in the next 50 years if no serious protective measures are implemented.

The Central region’s rivers have reportedly grown increasingly polluted, which would affect the Giant Freshwater Stingray. Animal health is an important indicator of the environment’s well-being. However, past cases of mass fish deaths show that it’s always difficult to pin down a culprit.

This time around, the Pollution Control Department and related agencies should show that they will forcefully address the matter.

There are hundreds of factories which could discharge toxic substances into public waterways or emit pollution into the atmosphere every day.

According to PCD’s Thailand Pollution Report from 2015, 9.59 million cubic metres of community wastewater were produced each day at the national level. Only 26.9% went through wastewater treatment before being released into the environment.

Unfortunately, nearby communities currently do not have the power to examine these factories because there is no legal requirement for the factory to make data on pollutant levels available to the public.

Currently, factories are required to submit pollution-related information only to government agencies such as the Industrial Works Department.

Communities should be able to play a more active role in protecting their homes or in holding industry accountable for destructive environmental incidents. The community itself could also monitor activities to prevent waste dumping.

The government should provide supportive laws and requirements to strengthen communities while taking serious action against polluters to show that the destruction of the environment will not be tolerated.

Source: Bangkok Post

A resident secures one of the 15 dead Giant Stingrays found floating in front of Wat Khu Thamsathit in Khlong Bangkantaek, which is linked to the Maeklong River in Samut Songkhram’s Muang district.
Photo: Pattarapong Chatpattarasill

Thailand: No rays of hope here
13th October 2016;

After dozens of endangered Stingrays died and more aquatic animals went belly-up on the Mae Klong River, why is it that the Department of Pollution Control and related state agencies are still in the dark about what caused the deaths?

Probably frustrated at the apparent hopelessness of the situation, a black banner bearing a message: RIP Mae Klong River and Himantura chaophraya, the scientific name of the dying Giant Freshwater Stingrays (Actually it’s Himantura polylepis Urogymnus polylepis), has been widely circulated among concerned citizens and environmentalists online.

Mae Klong River residents and aquatic culture farmers have every reason to feel let down by the pollution control authority, in particular, in this case. Also in the dark is the provincial industrial office which is authorised to regulate factories to ensure they comply with environmental protection rules. It has been almost two weeks since the Stingrays, a rare and magnificent creature that is considered among the largest freshwater fish in the world, started to die in large numbers on Sept 29.

The unusual deaths of the bottom-feeding large-sized Rays that are also classified as being endangered by the International Union for Conservation of Nature should have raised alarm bells with the pollution authority immediately. While it is possible that natural causes could be at play, a more likely explanation for the sudden deaths is that pollution is to blame.

Mae Klong River residents and conservation networks started to detect a possible surge in wastewater volume on Sept 27. There was no word from the authority at that time as to whether water quality in the river remained safe or whether there were any attempts to monitor the situation.

The pollution control authority failed to react even after the death toll of Stingrays increased to more than 20, or after commercially cultured fish and clams were found dead as well. It was only after the damage to the river and aquatic animals provoked an uproar from society that officials from the pollution control department went to collect water samples and sediment from the river.

Lab results of the water samples will not be available until tomorrow. The delay by the officials to react to the possible pollution problem is likely to result in it missing an opportunity to identify what exactly caused the sudden deaths of the Stingrays and other animals, and who should be held to blame.

But that is not the worst that the public can expect from the authority. While suspecting that wastewater discharged from factories located along the river’s course is likely to be behind the sudden death of the endangered species and other animals, the department conceded in the same breath that even with its delayed lab findings, it will be impossible to single out the factory that polluted the river.

The Mae Klong River incident does raise a serious question: What is the use of the pollution control authority if it cannot effectively monitor pollution levels in public waterways, cannot prevent illegal dumping of toxic waste and cannot find any culprits in the event such irresponsible acts occur?

The deaths of the endangered species of Stingray, whose population may have come down to only a hundred or so and become too small for it to be viable in the future, and the damage to commercial aquatic culture industry is a reminder that selfish behaviour seeking personal benefits over the country’s common good still exists.

A more worrying point that the incident has brought to the fore, however, is whether we have an effective mechanism to monitor the violations and to take those responsible for them to task. Considering what has happened in the Mae Klong River, the answer to the question seems bleak.

Source: Bangkok Post

A resident secures one of the 15 dead Giant Stingrays found floating in front of Wat Khu Thamsathit in Khlong Bangkantaek, which is linked to the Maeklong River in Samut Songkhram’s Muang district.
Photo: Pattarapong Chatpattarasill

Thailand: Stingray deaths spur checks
Pollution dept orders toxic discharge tests
By Apinya Wipatayotin, 12 October 2016;

Wastewater discharged from factories is likely to be behind a sudden spike in deaths of Giant Freshwater Stingrays (Urogymnus polylepis) in Samut Songkhram, but lab test results may not be able to provide a link to the culprits, says the Department of Pollution Control.

A lab test is needed to clarify the source of chemicals or toxic substances that killed the Rays and is expected on Friday, said Wicharn Simachaya, the department’s chief.

His team collected samples of water and sediment from different spots along the Mae Klong River, from Samut Songkhram to Kanchanaburi, for tests to identify heavy metals and chemicals that might point to the cause of the unusual deaths.

At least 15 Stingrays have been found dead since Sept 29.

Even with the lab findings, it will be impossible to single out the factory that discharged the wastewater, he said.

“Most factories are using the same chemicals, so it’s difficult to point to a wrongdoer,” he added.

The high death rate prompted authorities to collect more samples from nearby Don Hoi Lot, a local source of Razor Clams (Solen sp.), which have also started dying.

Meanwhile, Nantarika Chansue, a vet from Chulalongkorn University who disclosed the spike in deaths of the rare species of Rays on her Facebook, insisted tests showed the cause of the deaths was not natural, citing findings by the Animal Health Institute that found toxic contamination in the livers and kidneys of some of the dead Stingrays.

Toxins were found at 20 times the normal level which showed the kidney had to work hard to get rid of the toxin from their bodies, she said.

Three survivors being nursed also showed similar symptoms of being paralysed, resulting from toxic contamination.

“We can’t tell what kind of factory released the toxins, but it was clear the toxins were not from the farming sector because the amount of contamination was too high,” she said. She also ruled out natural causes as too many of the Rays had died.

She was concerned the Stingrays kept dying, as there are only about 150 left in the river.

Local communities believed the death was caused by sugar and ethanol-producing factories in Ratchaburi’s Ban Pong district.

An ethanol plant in Ratchaburi admitted that one of its waste water pipes broke, leading to wastewater discharges into the river. It is in the process of fixing it.

It said the incident happened on Sept 30, but the Stingrays started to die a few days before that. However, locals argued the leak started long before the factory claims.

Meanwhile, Prime Minister Prayut Chan-o-cha has ordered officials to find out the cause of the Stingrays deaths, saying the Rays should be conserved as they are an indicator of the condition of the river.

Officials were also instructed to look into the cause of the deaths of fish raised in baskets and take care of the fish farmers, the premier said.

Samut Songkhram governor Kanchat Tansatien said he instructed agencies to collect samples of water and sediment in four locations along the river to find out the cause of the deaths.

The locations which Stingrays regularly inhabit are near Wat Phet Samut Worawihan, Somdet Phra Buddha Loetla Nabhalai Bridge, both in Muang district, Somdet Phra Srisuriyendra Bridge in Amphawa district and Amarin Tharamat Bridge in Bang Khonthi district.

Referring to the mass deaths of Razor Clams in the province, Mr Kanchat said water quality was likely to be the cause. Tests would be conducted.

Source: Bangkok Post

Thailand: VMARC reveals stingray deaths triggered by toxic waste
12th October 2016;

The Veterinary Medical Aquatic animal Research Center (VMARC) revealed that massive Giant Freshwater Stingray (Urogymnus polylepis) deaths in the Mae Khlong River in Samut Songkhram were caused by toxic waste.

VMRAC Director Nantarika Chansue said lab results revealed that it was likely that the fish were killed by toxic waste from factories. She claimed their deaths were not triggered by natural causes.

Dr. Nantarika said even though it was not clear what type of toxic waste was found inside the fish, it was certainly not the kind that could be found in the nature. At least 50 Stingrays were killed in the river.

Pollution Control Department Director General Wijarn Simachaya said authorities will be able to identify the origin of toxic chemicals when more test results are released this Friday.

Legal actions are expected to be taken against responsible factories. Samut Songkhram Governor Kanchat Tansatien has instructed relevant agencies to investigate the cause of Stingray deaths.

Mr. Kanchat also said the recent massive deaths of Razor Clams (Solen sp.) in Don Hoi Lot were caused by algal blooms, not the same toxic waste water that killed the Stingrays. Meanwhile, Prime Minister Prayut Chan-o-cha ordered a quick probe into the problem as it is a direct threat to the ecosystem.

Source: National News Bureau of Thailand

Thailand: Razor Clams dying at Don Hoi Lot; more dead Rays found
By Chularat Saengpassa, 11th October 2016;

Razor Clams (Solen sp.) are dying off in the famous tourist attraction of Don Hoi Lot river delta in Samut Songkhram province, near the same area where dozens of Giant Freshwater Stingrays (Himantura polylepis) were recently found dead.

The number of dead Stingrays found in the Mae Klong River, which runs through Samut Songkhram and nearby Ratchaburi province, now stands at 45, Samut Songkhram’s fisheries chief Utai Singtothong said, as three more carcasses were found yesterday.

Water pollution – the suspected cause of the Stingray deaths – already has taken a toll on the Don Hoi Lot river delta.

“Water has turned red and smelled badly during the past three to four days,” Supap Kongraksa, a village head in Samut Songkhram’s Muang district, said yesterday.

Her team has been inspecting coastal zones after the shocking reports of the Stingray deaths.

“At dawn, I found many Razor Clams climbing up to the muddy surface at Don Hoi Lot. When my team caught them, we found them to be very weak and dying,” she said.

Don Hoi Lot is a famous seaside area that typically has a robust population of Razor Clams. Many tourists travel to Samut Songkhram specifically to visit the area.

“I am now worried that all the Razor Clams here will die,” Supap said.

Bandhit Pansawat, a coordinator for the Self-Managed Samut Songkhram Group, said Blood Cockles (Tegillarca sp.) in the area had also died.

“We also noticed that many small fish had headed out of the Mae Klong River to a connected small canal since September 29,” he said, adding that he was disappointed the authorities had so far said that the water quality was fine.

Utai said yesterday that his agency was in the process of examining samples from the river, as well as water from Don Hoi Lot. “Results should be available soon,” he said.

Last Friday, the Pollution Control Department announced that the amount of dissolved oxygen in Samut Songkhram’s Mae Klong River was sufficient to support life.

Weerakit Joerakate, who works with Kasetsart University’s Samut Songkhram Fisheries Research Station, said his team had collected water, soil and plankton samples along the Mae Klong River yesterday from Samut Songkhram and Ratchaburi provinces.

“We believe we will be able to identify toxic substances, if any are there, within five days,” he said.

Source: The Nation

Thailand: Giant stingrays under threat in Mae Klong River
By Pratch Rujivanarom, 9th October 2016;

Giant Freshwater Stingrays are facing extinction in the Mae Klong River, a leading marine biologist warned yesterday as mass deaths attributed to water pollution killed a large segment of the population.

As many as 20 Giant Freshwater Stingrays were found dead this week along the Mae Klong River in Samut Songkhram. The cause of death was still unknown yesterday, but researchers said poor water quality was a major cause of ecological damage.

Thon Thamrongnawasawat, deputy dean of the Fisheries Department at Kasetsart University, said he was concerned about the die-off affecting the rare species of Stingray (Urogymnus polylepis) in the Mae Klong River.

“Giant Freshwater Stingrays are rare fish due to the loss of their habitat and their low fertility rate. The sudden death of a large proportion of the population is very serious. It will take decades to recover the population to levels before the incident and if the situation get worse, we may lose this species of Stingray from the river forever,” Thon said.

Giant Freshwater Stingrays are viviparous fish that produce only one to four offspring at a time and it takes more than 10 years for the fish to mature and become ready to mate.

Given the recent loss of mature rays, it will be very difficult for the population to recover, Thon said.

The species, which is the largest of freshwater Stingrays, is listed as endangered by the International Union for Conservation of Nature and Natural Resources (IUCN).

The Stingrays are found in the Chao Phraya River basin, the Mekong River and various rivers in the Malaysian state of Sabah.

The population has decreased worldwide, with the IUCN reporting that the Stingray population in the Mekong River and Tonle Sap Lake had fallen by 50 to 95 per cent while in Thailand the population had declined by 30 to 50 per cent.

Meanwhile, local fisheries researchers are working to save the Stingrays with the head of Kasetsart University’s Samut Songkhram Fisheries Research Station, Weerakit Joerakate, reporting that two rays had been brought to the station for treatment.

“We received a report from local residents on Friday night that they had found one living female Stingray washed ashore. She was two metres wide and four metres long and it was estimated that she was more than 40 years old. Luckily, we could save this precious animal and bring her to the station. Right now her condition is better, as she can swim and move by herself, but we have to let her rest here until the river conditions are better,” Weerakit said.

“The count of dead Stingrays now is around 20, but it seems to be more because of a duplicate count. This is a destructive event for the Stingray population and we are doing our best to save as many surviving Stingrays as we can,” he said.

Thon said an analysis of water quality in the river had found that levels of dissolved oxygen (DO) in the river were very low. In some areas, DO levels were as low as one milligram per litre, while the level that is required to sustain marine life is six milligrams per litre, Thon said.

“From the observation of the mass fish death, big fish like Stingrays die first, while many smaller fish are still alive. This indicates that the low DO levels are responsible for the fishes’ deaths. However, there are many factors that can lower the water quality, such as water runoff during flood periods, wastewater from residential areas and pollution from industry,” he said. “We will need more tests and evidence to pinpoint what is the real cause of this incident and who is behind it.”

Source: The Nation

As many as 14 Manta Rays Stingrays have been found dead in Mae Klong River in Samut Songkhram province this week.
Photos: Witty Sangsornart

Thailand: Probe into Stingrays deaths
8th October 2016;

Authorities are trying to determine why as many as 14 Giant Freshwater Stingrays (Urogymnus polylepis) were found dead in Mae Klong River in Samut Songkhram province.

“It’s strange because they apparently didn’t die of water pollution. We have not seen any other fish dead in the river,” Samut Songkhram’s fisheries chief Uthai Singtothong said yesterday.

He said the provincial governor has convened a meeting of relevant officials to discuss the Stingrays’ deaths.

“We have sent their bodies for examination. We have also checked the quality of the river’s water,” Uthai said, adding that the results would be known soon.

Source: The Nation

Students look at a dead Stingray floating in front of Wat Khu Thamsathit in Khlong Bangkantaek, which is linked to the Mae Klong River in Samut Songkhram’s Muang district. A total of 15 Stingrays have been found dead in the river since late last month. Authorities are scrambling to determine the cause.
Photo: Pattarapong Chatpattarasill

Thailand: Mass Stingray deaths prompt alarm
Threatened species mysteriously turns up dead in the Mae Klong River
By Mongkol Bangprapa, 8th October 2016;

Mae Klong riverside residents in Samut Songkhram have expressed concerns about the recent and mysterious mass deaths of Giant Stingrays (Urogymnus polylepis), something they said is unprecedented in this western region’s key river.

Residents normally avoid catching Stingrays due to their superstitious beliefs, while the animals are also a barometer of the fragile ecosystem in the river.

A total of 15 Giant Freshwater Stingrays, a threatened species, have been found dead since Sept 29.

“I have never seen anything like this before,” said Ubon Chanbandit, a 60-year-old housewife and a former fisherman in Muang district.

“Dead fish were found in the river last year due to wastewater but for this many Stingrays to die like this, this is the first time I’ve seen it happen,” she said.

Sompon Wangcharoen, a 75-year-old retired public relations worker for Tai Had Tambon Administration Organisation (TAO), echoed Ms Ubon’s remarks, saying he has never seen this number of Stingray deaths since working at the TAO 20 years ago.

He said the river was once polluted by a sugar plant which released wastewater into the river in 2010, which resulted in the deaths of fish and prawns. But this time, the water did not give off a bad smell, which is the first indication of water pollution, he said.

Chatree Tharasaeng, head of the fisheries office in Samut Songkhram’s Muang district, said all parties concerned are expediting efforts to determine the cause of the Stingray deaths.

He said there was a recent drop in plankton as a result of a large amount of rainwater, which also leads to poor water quality. But it remains unconfirmed whether this can be linked to the Stingray deaths, he noted.

Piya Promsathit, Chief of the Regional Environment Office 8, said officials found that water samples in three locations upstream from the Mae Klong River in Ratchaburi had lower than standard levels of oxygen.

However, a joint effort is required from several agencies to confirm the cause of the Stingray deaths, including an examination of the dead stingrays’ tissue and an analysis of water in the river, he said.

Examining the biological characteristics of the river may take a week, he said.

The incident also sparked suspicions that some factories may have discharged polluted water into the western region’s major waterway.

An environmental protection group in Ratchaburi has filed a complaint against a Ban Pong-based sugar factory, suspecting it may have discharged foul water into the Mae Klong River.

Rattawut Wallathanaroj, secretary-general of the network for environmental protection and against corruption, said provincial industrial authorities took water samples from the factory’s outlet pipe to check for pollutants.

Mr Rattawut said the river banks are dotted with large industrial plants, some of which may be in breach of environmental regulations.

“It must be investigated whether 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 results of the tests on the discharge from the sugar factory.

“In fact, the factory does treat the water but regulations state it must store water for farm use, 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 is not known if the factory is to blame.

“We are working with officials in Samut Songkhram to establish the cause,” said the official, who asked not to be named.

Source: Bangkok Post