For 17 years, Zeb Hogan, a biologist, has been trying to find the world’s largest freshwater fish. On June 13, his staff discovered it — a large freshwater stingray, or Urogymnus polylepis.
The ray, hauled out of the murky waters of the Mekong River in Cambodia, measured 13 ft in size earlier than it was returned to the river. And at 661 kilos, it was 15 kilos heavier than a Mekong large catfish caught in Thailand in 2005. Dr. Hogan stated he had beforehand established that freshwater fish as the most important ever caught.
Whereas this species of large stingray has a particularly harmful venomous barb that may attain almost a foot in size, they aren’t often a menace to people. Extra typically, they wind up available in the market as a supply of low-cost protein.
Fishers in Cambodia first alerted Dr. Hogan and his staff at Wonders of the Mekong Challenge, which works to guard the Southeast Asian river’s aquatic variety and is sponsored by the U.S. Company for Worldwide Growth, that they’d caught a stingray bigger than anybody had ever seen. Staff members rushed to the small river island, known as Koh Preah, and lined up three industrial scales. Utilizing a tarp, they hoisted the stingray out of the water and onto the scales to confirm its weight.
The invention comes lower than a month after one other large stingray — that one weighing 400 kilos — was caught and launched close by. Two different monumental rays have additionally been caught this 12 months.
“The truth that the world’s largest freshwater fish was caught within the Mekong is exceptional,” Dr. Hogan stated. “It is a closely populated area, and the river faces a ton of challenges, together with a number of fishing.”
In one other first, Dr. Hogan’s staff was in a position to match the stingray with an acoustic tag to trace the animal for as much as one 12 months with an array of 36 underwater receivers that had been additionally not too long ago put in in a stretch of the river.
“That is the primary fish that we’ve tagged since having the array deployed,” stated Dr. Hogan, who can also be a analysis affiliate professor on the College of Nevada, Reno. Within the months forward, they plan to tag lots of of further fishes.
With so many huge stingrays caught in latest months and all of them feminine, Dr. Hogan believes this stretch of the river and the deep swimming pools it incorporates are a essential breeding floor for the species. The world can also be residence to freshwater dolphins, large soft-shell turtles, large catfish and large barb, which is within the carp household.
“So it’s a really distinctive place, and really understudied,” he stated. North American and European river techniques obtain way more scientific consideration.
Whereas breaking the world document was not scientifically vital, Dr. Hogan stated that the existence of this fish is an indicator for the well being of its ecosystem. He additionally hoped the invention remind the area people how particular this river is, and the way a lot it’s in want of saving.
Due to a mixture of things, together with dam building, overfishing and local weather change, large freshwater fish populations are typically in decline. And lots of species of huge fish are at risk of disappearing ceaselessly.
“In 2020, one of many contenders for the world’s largest freshwater fish, often known as the Chinese language paddlefish, was declared extinct,” Dr. Hogan stated. “That was very unhappy information, and it had me feeling like we had been going to see extra extinctions of those large fish, moderately than information being damaged.”
Luckily, the large stingrays aren’t the one large fish tales of late. In 2021, a record-setting 240-pound lake sturgeon was caught and launched within the Detroit River. And in Could, a virtually 300-pound alligator gar might have damaged the Texas state document for the freshwater fish, although the angler selected to launch the animal moderately than kill it and produce it in to be weighed.
“Whenever you hear tales about document fish, that’s a great signal,” Dr. Hogan stated.