The large stingray that was fished out of the Mekong River close to Stung Treng, Cambodia, on June 13, 2022.
Credit score: Wonders of the Mekong/Chhut Chheana
Blighted by drought and local weather change, overfishing, air pollution, and big dam development, the plight of the Mekong River has been well-documented over the past 20 years. However Southeast Asia’s largest river system remains to be able to producing the odd shock or report catch.
Because of fishermen working round Koh Preah island close to Stung Treng in Cambodia’s northeast, scientists say they’ll lastly determine the world’s largest freshwater fish – a 300-kilogram feminine stingray, named Boremei by locals, Khmer for “full moon.”
Measuring 4 meters from snout to tail, the large stingray broke the earlier report set in Thailand the place a 293-kilogram Mekong big catfish was found in 2005. That fish died earlier than it might be offered to environmental teams and – moderately sadly – was divided between villagers and reportedly fed the group for a number of weeks.
The newest catch, made on June 13, was luckier and extra vital on a number of fronts.
“In 20 years of researching big fish in rivers and lakes on six continents, that is the most important freshwater fish that we’ve encountered or that’s been documented anyplace worldwide,” stated Zeb Hogan, a biologist on the College of Nevada and head of the Wonders of the Mekong venture.
“That is a fully astonishing discovery, and justifies efforts to higher perceive the mysteries surrounding this species and the unimaginable stretch of river the place it lives.”
Stung Treng sits just under the Laos border and 4 Thousand Islands, the place the bottom rises and the Mekong, at its peak, thunders by waterfalls and big rock crevices, limiting fish migration.
Between Stung Treng and Kratie to the south lies a 200 kilometer stretch of river, which is dwelling to a number of uncommon and endangered species, and the invention of Boremei additionally affords some hope, given it was introduced on the heels of a grim report in regards to the Mekong dolphin.
Simply 89 dolphins have been registered between Stung Treng and Kratie and deaths by unlawful fishing are outpacing the dolphin’s skill to breed, which may undermine efforts to have these protected areas added to UNESCO’s World Pure Heritage Listing.
In 2020, the World Wildlife Fund reported scientists had found 224 new species of plant and vertebrate animals within the Higher Mekong area, protecting Cambodia, Laos, Myanmar, Thailand, and Vietnam.
These species included 155 vegetation, 16 fish, 17 amphibians, 35 reptiles, and one mammal, taking the entire variety of new species discovered on this area to three,007, made since 1997.
In accordance with the College of Nevada, there are greater than 30 species of freshwater fish that develop to greater than two meters in size and may weigh greater than 90 kilograms, together with air-breathing arapaima, alligator gar, and carp as massive as grizzly bears.
It additionally notes that current research present that international populations of big freshwater species have plummeted by nearly 90 p.c previously 4 a long time, twice as a lot because the lack of vertebrate populations on land or within the oceans.
Boremei was launched again into the Mekong after it was fitted with an acoustic tag, enabling biologists to study extra in regards to the stingray’s habits, the primary for a stingray caught in Cambodia.
Scientists stated the stingray, one of 4 sighted in current months, appeared robust and wholesome because it rapidly descended into the murky depths of the river.
“This report fish highlights the necessary connection between individuals, fish, and freshwater,” stated Hogan. “Giant fish are bellwethers of the well being of freshwater ecosystems worldwide – the fish are sending us a message and we have to take heed to it.
“It’s a sign to us to guard our rivers and lakes,” he stated.