An almost 4m-long, 300kg giant freshwater stingray was weighed, labelled and DNA tested before being released back into the water after being caught on a fishing line in the Cambodian stretch of the Mekong River in Stung Treng province on June 14.

A Fisheries Administration official in Stung Treng province and a team from the Wonders of the Mekong project and the Inland Fisheries Research and Development Institute (IFReDI) carried out the testing.

Srey Sam Vichet, head of the provincial fisheries administration, said on June 15 that the caught giant freshwater stingray weighed 300kg and measured 398cm from head to tail, with a width of 220cm.

It was the was third the time in recent weeks that a female giant freshwater stingray had been released back into the upper Mekong River, he added.

The stingray was caught on a fishing line on June 13 at 4pm in Koh Preah commune’s Koh Preah village in Stung Treng province’s Siem Bok district. It was not one released on May 23 because of their different sizes, Sam Vichet said.

That particular giant freshwater stingray was caught on a line in the Anlong Kampi Irrawaddy dolphin conservation area, and had unfortunately sustained some injuries.

He said three female freshwater stingrays had recently been released into the river in the commune – the first weighing 280kg on May 5; another weighing 143kg on May 23; and this latest 300kg specimen on June 14.

Fishermen were prohibited from catching the species as the removal of large females from the ecosystem harmed reproduction, he added.

“Large females produce a lot of babies, and they are a rare species in the world – giant freshwater stingrays are found in only very few countries,” Sam Vichet said.

Biodiversity researcher Sok Vichea said there are 15 species of stingray in Cambodia, both freshwater and salt water.

He said that giant freshwater stingray was the largest species of stingray in the world, and one of the most unique fish species in Cambodia, along with the Mekong giant catfish and the giant barb.

Giant freshwater stingrays grow to around 2m wide and 4m long, and have been recorded as weighing as much as 700kg.

“The giant freshwater stingray is found in Laos, Thailand and Cambodia, staying along the waters of the Mekong River,” Vichea said.