A 300kg giant freshwater stingray (Urogymnus polylepis) – found in Siem Bok district’s Koh Preah commune of Stung Treng province in the Mekong River last year – has been officially recognised by the Guinness World Records as the world’s largest recorded freshwater fish, according to Wonders of the Mekong.
Wonders of the Mekong, a conservation group supported by the US Agency for International Development (USAID), fitted an acoustic tag to the ray, named Boramey, before releasing it into the Mekong River last year.
“Since the release, we have gathered invaluable information on this magnificent ray through our acoustic tagging system, which will help us protect this endangered species,” it said in a social media post.
Officials from the Fisheries Administration’s (FiA) Stung Treng provincial cantonment, worked with a team from Wonders of the Mekong and the Inland Fisheries Research and Development Institute of Cambodia (IFReDI) to measure the ray, which was caught by fishermen in June 2022.
The specimen was 3.98m from its head to the end of its tail and 2.2m wide. It weighed 300kg. After the measurements were completed, an acoustic homing tag was attached and it was released back into the wild.
Sok Vichea, a Cambodian biodiversity researcher, explained at the time that while the Kingdom is home to 15 types of freshwater and ocean stingrays, the giant freshwater ray was nearly extinct, with few known to remain in the Mekong.
He said this species is one of three giant fish known to inhabit the Mekong, along with the Mekong giant catfish (Pangasianodon gigas) and Mekong giant bard (Catlocarpio siamensis).
“These species exist only in the Mekong in parts of Cambodia, Laos and Thailand,” he said.