Underwater acoustic receivers installed to track largest stingray ever caught
June 23, 2022
PHNOM PENH – Scientists from Wonders of the Mekong and the Fisheries Administration (FiA) have installed 36 underwater acoustic receivers along the upper Mekong River in Cambodia to better track the movements of a ray believed to be the largest fish in the world. never caught fresh water, excluding beluga. sturgeons, which also occupy saltwater environments.
On June 13, a 42-year-old Cambodian fisherman, Moul Thun, a resident of Koh Preah village, Siem Bok district, Stung Treng province, caught the female giant freshwater stingray (Urogymnus polylepis), a listed species ” endangered” in the International Union for Conservation of Nature (IUCN) Red List.
The specimen weighed 300kg and measured 398cm from its snout to the tip of its tail, with a width of 220cm, which Wonders of the Mekong scientists say dethroned the previous record holder, a giant catfish. of 293 kg Mekong caught in Thailand in 2005.
The ray was released into the Mekong on the evening of June 14, after being weighed, fitted with an acoustic tag at the base of its tail, and named “Boramy” – which translates to “full moon” in Khmer – for the twilight moon shining on the horizon when it was released, according to Chea Seila, program manager for the Wonders of the Mekong in Cambodia.
The three dozen acoustic receivers were installed along the Mekong River between the southwestern province of Kratie where it meets Kampong Cham, north of Stung Treng, to the border with Champasak province in Laos.
“These acoustic receivers are a new technology that allows biologists to understand the mysterious life processes and behaviors of living things, especially the rarest and largest freshwater giant in the world that we have just encountered and let go,” Seila said.
She said the FiA, under the aegis of the Ministry of Agriculture, Forestry and Fisheries, is involved in a conservation project which aims to establish a network of anglers to report catches of giant or endangered fish. of extinction, including stingrays.
“We are very happy and proud of the involvement of local fishermen in the protection and conservation of rare and endangered Mekong fisheries, such as the giant ray,” she said. “We call them heroes because without their participation our efforts would not have been successful.”
The Mekong River originates on the Tibetan Plateau, flows through China, Myanmar, Thailand, Laos, Cambodia and Vietnam, and is rich in biodiversity, but overfishing, dam construction and water pollution water threaten the fragile ecosystem of the river.
Zeb Hogan, an American fish biologist at the University of Nevada, Reno, who leads the Mekong Wonders, said: “The discovery of rays is proof that the natural world can still produce new and extraordinary discoveries, and that many of the largest aquatic creatures unfortunately remain understudied.
“In 20 years of research on giant fish in rivers and lakes on six continents, this is the largest freshwater fish we have encountered or documented anywhere in the world.
“This is an absolutely astonishing discovery, and one that justifies efforts to better understand the mysteries that surround this species and the incredible stretch of river where it lives,” he said.