Why do giant rays disappear mysteriously?

In October 2016, more than 70 children. The announcer is the researcher, explorer of National Geographic, Zeb Hogan.

This event for nature lovers, with expertise is very alarming, because the number of giant freshwater stingrays is already very small. The giant freshwater stingray has been listed as a danger by the Union for the Conservation of Nature and scientists say they need to learn more about biology and quantity. the rest of them.

Dead series

But why is the giant freshwater stingray , Thailand's pride, dead in a series of mysteries? Thai officials, researchers around the world have tried to find answers but failed. Thai officials say testing water quality where rays were found, they found a slightly higher rate of alum than elsewhere. But it is unclear whether this is related to the cause of giant stingrays dying mass.

This is not the biggest child.

Some Thai environmentalists have suspected that a certain plant may have poured ethanol into the river, causing the giant rays to poison. Others believe that the fish may have been poisoned by cyanide, possibly stealing fishermen, with the goal of destroying many other fish species rather than targeting giant rays.

But all these hypotheses are not convincing. Why only giant stingrays die?

Giant freshwater stingrays are rarely targeted by fishermen, because their flesh is not good. They are very big and strong, most common fishing gear cannot be loaded. Sports people who meet them are also very fragile and need to break the charge no matter how big and big they need.

Recently, a giant stingray is found in the Mae Klong River. According to researcher Hogan, it is 4.2 meters longer, 2.4 meters across, weighing 363kg. Zeb Hogan is a professor of biology at the University of Nevada, the host of the Monster Fish on television channel Nat Geo Wild worldwide.

Zeb Hogan and a freshwater stingray.

Although not hunted by fishermen, giant freshwater rays often catch nets and die. Pollution, oil spill and the operation of hydropower dams also negatively impact their habitat.

Although it is unclear why the giant rays cause mass deaths, but according to researcher Zeb Hogan, one thing is clear.'In the long run, it is necessary to limit polluting factories along the river banks to improve the health of waterways and the environment in order to save the giant rays,' he said.

Half-ton fish

Hogan added, giant freshwater fish and mammals (freshwater dolphins in Southeast Asia or China) are among the world's most endangered species due to pollution, Overfishing, human activities along the river (hydropower vessels, dams).

According to the Ecowatch site, giant freshwater stingrays are increasingly divided into small groups built by large hydroelectric dams. This leads to a decline in their genetic diversity. Large rays, which prefer to reside in the sandy bottom of the river, are now in danger because of sedimentation because the river is blocked by many hydropower sections.

The body of a stingray died of unknown cause.

Due to the large, bizarre form, freshwater stingray giants are hunted by the people to make ornamental fish in the house. Going to Google to type in the phrase 'selling freshwater rays' will result in more than 479,000 results immediately. Giant freshwater rays are only found in Southeast Asia (mainly Thailand) and northern Australia.

These large rays can weigh more than 450kg. As a relative of the more diverse species of saltwater rays, the giant freshwater rays have only been known since 1990, when scientists discovered them. Although freshwater rays have been found in brackish areas, it is unclear whether they will ever go to the sea. And the number of them in the wild is not yet determined, although the decline is obvious.

In 2008, Englishman Rick Humphreys stumbled on a freshwater stingray on the Maeklong river. The fish, according to Rick's description, was as heavy as a 5-year-old, whose tail was more than 1.5 meters long. But because Rick is from Europe, he thought it was a monster. He later found out that it was just a 'children' stingray, because his father was 10 times bigger and heavier.

But the event was still new to people like Rick Humphreys and his Telegraph had a long post about Rick and the stingray.

And although he has studied giant stingrays for a while, Dr. Zeb Hogan says there are still too many mysteries around this animal.

'I have a lot of questions about this stingray,' said Hogan. 'Is it really a freshwater fish? Where does it breed? Does it migrate and how? '.

Hogan said he had heard some stories that Cambodian fishermen had caught 500kg of rays with a wingspan of 4.3m.

Giant stingray is hunted for pets.

But in the five years of research and search, he has never seen a child of that size.

In the mass of giant freshwater stingrays, it was found in the area where two children were alive but very weak. Both children are pregnant females (stingrays give birth to babies, do not lay eggs). One was named Mae Buaban, the other was Mae Nongpho. Both recover very quickly. But suddenly one day, Mae Nongpho quit eating and died very quickly after only one day. People cut fish for examination and found that the cause of death was due to being infected.