June 7, 2022
Kingdom’s Upper Mekong likely last natural habitat for iridescent sharks

Researchers and officials from the Wonders of the Mekong said that the Cambodia’s Upper Mekong River system is likely the last surviving natural habitat for the endangered Pangasianodon hypophthalmus or iridescent shark.

The iridescent shark or iridescent shark catfish is native to the rivers of Southeast Asia and is endangered. Despite being endangered, the number of the population is unknown. Wonders of the Mekong stated that the species is important to the Mekong and fishing of the fish is an important commercial activity.

A new study supported by the Mekong River Miracle Project recently recorded a decrease in the size and population of the fish by analysing information from long-term fishing and tracking of juvenile fish in the Mekong and Tonle Sap over the last two decades. Total annual catch decreased from 236,952 kg in the 2000-2001 fishing season to 7,293 kg in the 2017-2018 fishing season.

The average body length of the species has decreased from 31 cm in 2001 to 13 cm in 2019. Large numbers of juveniles also declined during this period and was found to be associated with overfishing of the species.
https://www.khmertimeskh.com/501089644/ ... nt-sharks/

From wikipedia:


P. hypophthalmus migrations in the Mekong River
Orange: March to May
Dark green: May to September
Red: October to February
Shaded region: spawning region of the southern Mekong population between Khone Falls and Kratie

Rare endangered Mekong giant salmon carp caught in Stung Treng

Cambodia News, Stung Treng Province: Fishermen in Stung Treng Province have just caught a rare species of fish, the Aaptosyax grypus, in a remote area. This species of fish has been missing from the Cambodian river for many years.

Researchers say that Aaptosyax grypusis is a rare species that is classified on the International Union for Conservation of Nature (IUCN) Red List.

From wikipedia:
The giant salmon carp (Aaptosyax grypus), also termed the Mekong giant salmon carp, is a species of freshwater fish in the family Cyprinidae and the single species in the monotypic genus Aaptosyax. It is endemic to the middle reaches of the Mekong River in northern Cambodia, Laos and Thailand.
Its population is much reduced (>90%) as a result of overfishing and habitat degradation, and it is now considered Critically Endangered.
This fish can reach a length of 130 centimetres (51 in) and weight of 30 kilograms (66 lb).


On the same topic, see also:
Cambodia Catches World’s Biggest Freshwater Fish!
newsworthy/cambodia-catches-world-bigge ... 50221.html

How the World’s Largest Freshwater Fish Grew to a Whopping 660 Pounds
The Mekong River in Cambodia regularly produces 13-foot giant stingrays, scientists confirm. This is how.
By Tim Newcomb
Jun 29, 2022

If you’re a fan of giant fish, you already know about the Mekong River. Now, familiarize yourself with the new record-holder in the largest freshwater fish category: a giant stingray that measures about 13 feet long and weighs 660 pounds. Earlier this month, a local fisherman caught the beast in the Mekong River, located in northeastern Cambodia.

The stingray—which researchers with the Wonders of the Mekong conservation project saved—beat out the previous freshwater record-holder, a 646-pound catfish found in Thailand in 2005, also in the Mekong River. But how did these fish become so huge in the first place?

Zeb Hogan, Ph.D., a research biologist at the University of Nevada, Reno and director of the Wonders of Mekong project, tells Popular Mechanics that finding a fish of this size offers “an indication that this stretch of the Mekong River, the longest remaining free-flowing section, is still relatively healthy.”

Hogan says giant stingray populations have declined in other regions of southeast Asia more heavily impacted by pollution, dams, and overfishing.

The Wonders of the Mekong project, funded by the U.S. Agency for International Development, has partnered with the Cambodian Fishers Administration and worked with local communities to improve conservation efforts along the river. When the fisherman—who was financially compensated at market rate for his catch, even though the fish went back into the river—saw what he’d pulled in from the river, he contacted scientists with the project, who documented the fish and tagged it with a tracking device before it was released back into the waterway in order to study it.

But getting so large was more a product of space and food access than anything else.

“The Mekong is one of the largest and most productive rivers in the world,” Hogan explains. “Over two million tons of fish are harvested from the Mekong River each year. So, historically, the Mekong has been a great place to be a big fish. In fact, the Mekong River is home to many of the world’s largest freshwater fish: giant freshwater stingray, giant barb, giant pangasius, seven-striped bard, giant wallago catfish, and goonch catfish.” The area is also home to freshwater dolphins and giant soft-shell turtles. A handful of giant stingrays have already been seen in the area this year, leading researchers to believe the spot could be a popular spawning location.

“Unfortunately, populations of most of these species have plummeted, and some are now on the brink of extinction,” Hogan says. “It’s an issue throughout Asia, where populations of giant freshwater fish have declined by over 95 percent since 1970.”

Ronald Oldfield, Ph.D, a senior instructor at Case Western Reserve University, tells Popular Mechanics that capturing such a large fish in the Mekong River shows it “might not be too late and the river might still be capable of supporting such large fishes if it is managed wisely.”
https://www.menshealth.com/trending-new ... 60-pounds/

Endangered Hairy-Nosed Otter Found in Cambodia
AKP Phnom Penh, July 01, 2022 --

The world endangered hairy-nosed otter (Lutra sumatrana) was found in Cambodia forest recently, according to the Wonders of the Mekong.

This species is endemic to Southeast Asia, meaning it is only found within Southeast Asia and nowhere else. It is locally known as the Sumatran otter or Black otter because of its dark coat colour, different from the gray coat seen on smooth coated otters.

In Cambodia, they have been identified around the flooded swamp forests of Tonle Sap Lake. They eat especially fishes, crustaceans, snakes, lizards, and frogs.

The hairy-nosed otter has been included on the Red List of the International Union for Conservation of Nature as endangered species. It is one of most rare of the 13 otter species in the world.

It had not been seen since 1998 and the team of the Wonders of the Mekong found it with the use of camera trapping.
By Pheng Somany
AKP

Symbolic Mekong Endemic Fish Species Rediscovered in Cambodia
AKP Phnom Penh, July 18, 2022 --

The giant salmon carp (Aaptosyax grypus), a symbolic Mekong endemic fish species, has been rediscovered in Cambodia.

According to the Wonders of the Mekong project, for the last few decades, people in Cambodia have been unable to catch the elusive giant salmon carp (Aaptosyax grypus). In fact, most people thought that the species had completely disappeared from the Mekong region, especially in the Mekong River in Cambodia.
However, on June 28, 2022, a six-kilogramme giant salmon carp, with a standard body length of 74cm and a total body length of 88cm, was caught by a fisherman in the upper part of the Sesan 2 hydropower reservoir.

The giant salmon carp (Aaptosyax grypus) is a unique fish species that lives primarily in deep pools in the Mekong River in central Thailand and Laos. In Cambodia, the giant salmon carp, known in Khmer as “Trey Pasanak”, lives in the upper part of the Mekong River in Kratie and Stung Treng provinces.

"The Trey Pasanak is a rare and endangered fish species that is under-researched, and its numbers are poorly recorded because it is not a target fish for fishermen. Its presence is surprising and very interesting to me," said Dr. Chaiwut Grudpan, from the Department of Fisheries of Obun Ratchathani University, Thailand, who specialises in identifying fish in the Mekong region.

Mr. Chan Sokheng, Deputy Director of the Fisheries Technology Research Office of the Inland Fisheries Research and Development Institute of the Fisheries Administration and the author of the book "Freshwater Fish in the Kingdom of Cambodia (Characteristics and Brief Biology)" which contains information on a total of 388 species of fish, including brackish water fish species, expressed his excitement with the presence of Trey Pasanak as he has been tracking the fish species in Cambodia for 30 years. "I look forward to working with the Wonders of the Mekong project to conduct research that informs effective conservation of this endangered species," he said.

In Cambodia, the giant salmon carp, or Trey Pasanak, is found in the upper Mekong River. Because it is very rare, most Cambodians have never seen or heard about the fish species. Trey Pasanaks can grow very large, up to a maximum standard body length of 130 cm and a maximum weight of 30 kg. The fish has scales covering its elongated body, and a peculiar knob on its lower jaw. The giant salmon carp is a fast-swimming predator that feeds on other fishes. The giant salmon carp is classified as “Critically Endangered” on the IUCN Red List of Threatened Species.
- AKP

A Giant Mekong Catfish Released and Tracked
AKP Phnom Penh, December 28, 2022 --
A giant Mekong catfish, locally known as Trey Reach belonging to Cambodia's second biggest freshwater fish species, was released recently with a tracking device for conservation purpose.

The work was led by the Fisheries Administration of Kandal province in collaboration with the Inland Fisheries Research and Development Institute.

Caught earlier by local fishermen, the Giant Mekong catfish weighted 46 kilogrammes and was 157 centimetres long was released into the Mekong River in Prek Tamak commune, Ksach Kandal district of Kandal province.


Giant Mekong catfish was on the International Union for Conservation of Nature (IUCN) Red List of Endangered Species and its fishing, buying, selling, and transporting have been strictly banned by Cambodian authority since 1956.

It belongs to the top three largest fish species of Cambodia which are giant freshwater stingray, giant Mekong catfish, and giant barb.

Giant Mekong catfish can reproduce from the age of 6-8 years old and can live up to 60 years.

The attached tracking device will allow fisheries scientists to understand the traffic and living situation of the fish and support it as needed.
By Lim Nary
AKP

Two Mekong Giant Catfish and Thousands of Other Endangered Fish Released into Nature
AKP Phnom Penh, January 16, 2023 --


(Photo: Wonders of the Mekong)
Two critically endangered Mekong giant catfish and thousands of other endangered and ecologically important fish were released at the junction of the Tonle Sap and Mekong Rivers to spotlight the plight of a species whose populations have decreased up to 99 percent in recent decades.

According to a recent joint press release, Scientists hope it will lead to more concerted and coordinated conservation action, including greater outreach to communities living along the Tonle Sap and Mekong rivers.

H.E. Has Sareth, the Secretary of State of the Ministry of Agriculture, Forestry and Fisheries; H.E. Neth Pheaktra, the Secretary of State of the Ministry of Environment; Hanh Nguyen, United States Agency for International Development (USAID) Acting Mission Director; and Dr. Zeb Hogan of the USAID-funded Wonders of the Mekong project presided over the release ceremony near the Royal Palace in Phnom Penh.

Also present was Mrs. Cheng Mouychhen, the fish farmer who reared the released Mekong giant catfish in her ponds. The catfish, weighed about 100 pounds (between 45-50 kilogramnes) and measured over five feet (1.6 metres). Among the other fish released were giant barb, a critically endangered carp species known as the “National Fish of Cambodia,” and striped catfish, a highly migratory fish that was once a staple food in the region but has seen sharp declines and is now classified as endangered.

“It is essential that we work together to save and conserve ecologically important and critically endangered fish species, like the Mekong giant catfish, in order to keep the Mekong River healthy. This will conserve natural ecosystems to support communities, wildlife, and economic activity across Cambodia,” said Nguyen.

"The addition of these fish, together with parallel efforts to protect wild fish and their habitats, represent a significant contribution to the persistence of these species in the wild,” said Dr. Hogan.

The giant catfish have all but disappeared from rivers outside Cambodia. Today, the Southeast Asian country is widely recognised as being the best hope for the persistence and recovery of the species, as well as other Mekong giants like the giant carp, giant freshwater stingray, wallago catfish, and seven-striped barb.

The Ministry of Agriculture, Forestry and Fisheries (MAFF), through the Cambodian Fisheries Administration (FiA) and the Inland Fisheries Research and Development Institute (IFReDI), collaborate with Wonders of the Mekong to tag and release many endangered fish. "We want to encourage policies that enable this important resource to thrive in the wild," said H.E. Has Sareth, Secretary of State.

Mrs. Mouychheng, representing the deep commitment of local communities, said “I am happy that my family can contribute to endangered fish conservation. This is what my husband wished before he passed away, to release these fishes back into the Mekong River.
By Phal Sophanith
- AKP

Fisherman Hands over Giant Barbs to Wonders of the Mekong Project
AKP Phnom Penh, March 15, 2023 --

Fishers from dai row four have handed over four endangered Giant Barbs (Catlocarpio siamensis) to the Wonders of the Mekong project (WOM) in order to contribute to the WOM’s efforts in protecting this fish species, one of the rarest on earth.

According to the WOM’s news release yesterday, on Mar. 9, the four Giant Barbs, weighing between 15 and 21 kilogrammes, were moved from the dai fishery to a new home. The fish have been placed in cultivation ponds at the Freshwater Aquaculture Research and Development Centre in Peam Ro commune, Peam Ro district, Prey Veng province.

They will be held there until they can be safely released back into the river during the wet season when fishing activities are closed for the year, it underlined.

Fishers and WOM staff partnered with the Inland Fisheries Research and Development Institute of Cambodia and the Fisheries Administration Freshwater Aquaculture Research and Development Centre to transport and ensure the safety of these fish, the source added.

The Giant Barb is a national symbol of Cambodia and the largest carp species in the world. “We applaud the efforts of these fishers to contribute to a sustainable future for Cambodian fisheries,” said the news release.
By Phal Sophanith
AKP (Photos: WOM)

UPDATE
Tracking Boramy, World’s Largest Freshwater Fish, One Year Later

Stung Treng, Cambodia. The Wonders of the Mekong research project, funded by the U.S. Agency for International Development (USAID), uncovered clues that will help save the endangered megafish and the river where it lives. Last year’s discovery of a 661-pound giant freshwater stingray launched a new initiative by the United States government to study and protect one of the largest, most mysterious creatures on the planet.

The scientists dubbed the stingray “Boramy”, which means full-moon in Khmer. Over the last twelve months, in collaboration with the Fisheries Administration, scientists have been tracking the record-breaking stingray. After its capture in June 2022, Boramy was fitted with an acoustic tag before being released back into the river. The data gathered revealed that despite its enormous size, the female giant has a remarkably small home range, centered in a bio-rich but threatened stretch of the Mekong River in northern Cambodia.

Scientists know very little about the giant freshwater stingray, a species whose population has dramatically declined across its Southeast Asian region. This month, the USAID-funded studies will publish valuable findings. “The Mekong River, which runs through six Asian countries, is a global biodiversity hotspot and home to almost 1,000 different species of fish, including the world’s largest freshwater stingray,” says Kerry Pelzman, USAID/Cambodia Mission Director. “USAID is proud to join efforts to safeguard the wonders of the Mekong and to protect endangered species to help sustain Cambodia’s rich fisheries and livelihoods for millions of Cambodians.”

“This new information about the stingray and other critically endangered fish is crucial to the protection of Cambodia’s most iconic animals and the preservation of a river that provides food and livelihoods for millions of people,” says Zeb Hogan, a biology professor at the University of Nevada, Reno, who leads the USAID-funded Wonders of the Mekong research project that initiated the study. “The giant stingray is now at the center of a larger debate about the fate of the Mekong, and how to balance river basin development with environmental stewardship so that the bountiful Mekong can continue to provide for people in the region for generations to come.”

Globally, the International Union for Conservation of Nature has assessed the giant stingray as endangered due to population declines as high as 79 percent over the last century. ៕
- NKDNews

^ More from Science magazine:

World’s largest freshwater fish draws attention to delicate ecosystem
Scientists race to gain insights into the Mekong River’s disappearing giants—and how to save them
30 May 2023 5:40 pm
By Richard Stone

Late one night last summer, Seila Chea got an urgent call from a fisherman on the Mekong River in northeastern Cambodia. He’d hooked an endangered giant freshwater stingray—and it was a monster. Chea, project manager for the Wonders of The Mekong initiative, quickly organized a posse that sped out to the river to bargain for the creature’s life. Nearly 4 meters from snout to tail, the female weighed in at a hair under 300 kilograms, making her the world’s largest known freshwater fish.

“It was a full moon that night,” Chea says, “so I named her Boramy,” the Khmer word for full moon. The scientists paid market price for her meat, about $600, implanted a radio tag at the base of her tail, and set her free.

Hydrophone tracking of Boramy over the past year has given scientists a new window into the behavior of the enigmatic giant freshwater stingray, or whipray (Urogymnus polylepis), Chea and her colleagues report in the current issue of the journal Water. In the months since Boramy’s release, the team, working with the Joint Environmental Monitoring Programme of the Mekong River Commission, has tagged nearly 300 more fish from 27 species in Cambodia and Laos.
https://www.science.org/content/article ... -ecosystem