The Record Size of the Giant Mekong Stingray is Just Part of this Stunning Fish Story
The Record Size of the Giant Mekong Stingray is Just Part of this Stunning Fish Story
The 661-pound stingray caught, tagged and released in Cambodia signifies the resilience of giant river fish and the need to shape development to sustain such biological wonders.
From my pre-Substasck days: There's a good chance you saw one of the news flashes about the world's biggest known freshwater fish - a 661-pound, 13-foot-long giant stingray - caught, tagged and released in the Mekong River about 140 miles northeast of Cambodia's capital, Phnom Penh. Let's get beyond the "wow" factor.
The female stingray, hauled in on June 13, 2022, by fishermen who quickly alerted biologists, is extraordinary for its size - with biologists saying its weight topped that of the previous freshwater record holder, a 646-pound Mekong giant catfish caught in Thailand in 2005.
But more significantly, this fish and another giant stingray - a mere 400-pounder caught in the same region in May - show the resilience of this species, Urogymnus polylepis, amid pressures building in one of the most heavily fished rivers systems in the world.
The fish discoveries also reinforce how important it is to shape regional development with conservation in mind.
The Mekong, its tributaries and the giant adjoining Tonle Sap Lake produce an estimated $11 billion in wild fish harvests each year. Rising impacts from nearby deforestation and dams threaten many species - with climate change and rising seas adding another layer of risk.
The challenges to the Mekong's river giants are mirrored in river basins around the world, threatening species like this stingray, the giant catfish and various massive sturgeon, paddlefish and other anadromous species (those spending part of their lives at sea). It's worth noting that the murders of two Indigenous defenders in the Amazon River basin have been linked to poachers targeting a giant river fish there, the pirarucu.
This record Cambodian stingray, fitted with an acoustic tag before it was released, might have ended up in a market if a multi-year research and conservation initiative, The Wonders of the Mekong, had not already developed relationships with fishing communities in key spots and encouraged them to pass along word of rare or unusual catches.
The project is run by scientists from the University of Nevada Reno's Global Water Center and the Inland Fisheries Research and Development Institute of Cambodia with funding from the U.S. Agency for International Development.
Back in May, when the 400-pounder was caught in a 260-foot-deep Mekong pool, I hosted a pop-up Sustain What conversation with two leaders of the Mekong project - the biologists Zeb Hogan and Sudeep Chandra, both from the University of Nevada, Reno. (You may recall Hogan's fantastic seven-season "Monster Fish" series on Nat Geo Wild.)
In our chat, Chandra described the Wonders of the Mekong project focus on building conservation-minded communities:
"What our project is trying to do is embed ourselves and work with the community to try to understand what their sense of the habitats are, but also to establish more of a catch-and-release system to try to understand the ecology, the fish. What's hopeful to us is the idea that we caught one of these. They're still in the system, even after 20 years of big changes that are happening now."
I hope you'll watch (and share!) the full conversation on Facebook, Linkedin, Twitter or YouTube:
I'll be appending some excerpts below when time, but you can read the rough transcript on Trint in the meantime and comment or pose questions.
One of the most important aspects of the project is how it builds a network across society - from scientists and conservationists to local fishing-community elders and government officials. Explore this list of Mekong Conservation heroes to get the idea. Here are two who illustrate that range - Hor Sam ath, Deputy Chief of the Sdey Kroam Rohal Suong Community Fishery Committee, and Buth Chanmeta – Awareness and Outreach Senior Officer at WWF–Cambodia.
The project's revelations have also begun to make the Mekong's biological wonders a source of national pride. A news release from the University of Nevada today included this statement from a senior Cambodian official:
"The discovery of this world record stingray indicates the special opportunity we have in Cambodia to protect this species and its core habitat," said His Excellency Poum Sotha, Delegate of the Royal Government, Director General of the Fisheries Administration. “In partnership with the Wonders of the Mekong project, and together with other countries in the Lower Mekong Basin, the Inland Fisheries Research and Development Institute of Cambodian Fisheries Administration will host a meeting to map out a regional species conservation action plan and solidify safeguards for the river, wildlife, fisheries and local communities.”
An elusive giant
Little is known about the habits of this elusive stingray. But the tagged specimen can now be monitored for up to a year using an array of three dozen listening devices distributed along the Mekong up to the Laos border, the Wonders of the Mekong researchers said, noting that they are collaborating with biologists on the Laos portion of the river, allowing transboundary monitoring of fish. (Learn more about that monitoring effort in this post by Fishbio, a company working on fish monitoring and conservation projects there and around the world.)
Much of what's happening in the Mekong brings to mind the reporting I did for a couple of decades along the Hudson River - half a world away. There, the elusive giant was - and remains - the Atlantic sturgeon, a species prized for centuries for its roe (we call it caviar) and flesh.
In the 19th century, this sturgeon, growing up to 20 feet in length by some estimates, was so plentiful it was nicknamed "Albany beef" as cheap pub fare. Read this 1927 New York Times article for an early look at what happened next. By the 1990s catches had plunged nearly to zero. The fisheries were shut down and the species was added to the Endangered Species List.
\As a journalist, I've been a witness to this species' achingly slow return, having the chance to accompany state biologists on netting and tagging expeditions, and even getting to help return one fish - a small 120-pound male - to the river after it was measured and tagged. You can watch the video here:
Writing for National Geographic, I broke the story of the 2018 side-scan sonar detection of a sturgeon in the Hudson estimated at 14 feet long and an estimated 750 pounds.
John Madsen, University of Delaware
I mentioned the Hudson River saga in my conversation with Sudeep Chandra and Zeb Hogan, and Hogan offered this observation, aware that even the Hudson has a long way to go, but does offer a vision of what's possible:
That mirrors what we saw on the Mekong River last week - this catch and release of a 13-foot stingray. Those fish still exist in the Mekong River. The pieces are not lost yet. We haven't seen wide-scale extinction yet. Of course, the region is going to move forward and develop. But the decisions being made now [can] keep enough of those pieces in place to keep these amazing animals around, to keep the river functioning relatively naturally so it stays productive and provides fisheries for everyone.
The Hudson offers us hope because now the sturgeon are back but also provides lessons. How can the Mekong region move forward without losing these amazing animals that still occur in the river? We heard from our Cambodian colleagues, most people in Phnom Penh in Cambodia didn't realize that the Mekong was home to these amazing fish. And so I think it was a real eye opener for a lot of Cambodians as well, just to be surprised and kind of amazed at that. These animals live in the river in their backyards.
Here's hoping that these magnificent fish inspire us all to find way to mesh human needs with those of Earth's other inhabitants.
Resources
The Mekong Fish Network website has an informative series of illustrations showing the wide ranging habits of the river's big fish.
Follow the Wonders of the Mekong project on Instagram and Twitter at @MekongWonders.
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