6 endangered Mekong giant catfish – one of the world’s largest and rarest freshwater fish – spotted in Cambodia

Six critically endangered Mekong giant catfish – one of the world’s largest and rarest freshwater fish – were caught and released recently in Cambodia, reviving hopes for the species’ survival.

Underwater giants can grow up to 10 feet long and weigh up to 660 pounds, or as heavy as a grand piano. They are now only found in the Mekong River in Southeast Asia but in the past they inhabited the 3,044 km long river, from where it leaves Vietnam to its northern reaches in China’s Yunnan province.

The species’ population has declined by 80% in recent decades due to increasing pressure from overfishing, dams blocking the migratory path of fish following spawning and other disturbances. According to the World Wildlife Fund, some experts believe there may be only a few hundred Mekong giant catfish alive.

Few of the millions of people who depend on the Mekong for their livelihood have ever seen a giant catfish. Finding six giants, caught and released within 5 days, is unprecedented.

The first two were on the Tonle Sap River, which empties into the Mekong River not far from the Cambodian capital, Phnom Penh. They were given identity cards and released. On Tuesday, anglers caught four more large catfish that totaled two feet longer than 6.5 and weighed 264 pounds and 288 pounds, respectively. The fish caught were apparently migrating from their floodplain habitats near Cambodia’s Tonle Sap Lake along the North Mekong River, possibly to breeding grounds in northern Cambodia, Laos or Thailand.

“It is a hopeful sign that these species are not close, as in the next few years, to the risk of extinction, which gives conservation activities time to start and continue to bend the curve of decline and recovery,” said Dr. Zeb Hogan, a University of Nevada Reno research biologist who leads the US Agency for International Development-Wonders funded Mekong project.

Much is still unknown about the giant fish, but over the past two decades a joint conservation program of the Wonders of the Mekong and the Cambodian Fisheries Administration has caught, tagged and released nearly 100 of them, gaining insight into how catfish migrate, where they live and their health. of animal species.

“This information is used to establish migration areas and protect habitats to try to help these fish in the future,” said Hogan.

The Mekong giant catfish is woven into the cultural landscape of the area, depicted in 3,000-year-old cave paintings, revered in mythology and considered a symbol of the river, whose fisheries feed millions and are worth $10 billion a year.

Local communities play an important role in environmental conservation. Fishermen are now aware of the importance of reporting bycatch of rare and endangered species to authorities, enabling researchers to access areas where fish are caught and measure and photograph them before releasing them.

“Their cooperation is essential to our research and conservation efforts,” said Heng Kong, director of the Inland Fisheries Research and Development Institute of Cambodia, in a statement.

Besides the Mekong giant catfish, the river is home to other large fish including the salmon carp, which was thought to be extinct until it was spotted earlier this year, and the giant sting ray.

That four of these fish were caught and tagged in one day is probably “the biggest Mekong fish story of the century”, said Brian Eyler, director of the Southeast Asia Program of the Washington-based Stimson Center. He said seeing them confirms that the annual fish migration is still strong despite all the pressures facing the environment along the Mekong River.

“I hope that what happened this week will show the countries of the Mekong and the world that the mighty fish of the Mekong are special and need to be preserved,” he said.

Threats to endangered aquatic species

In addition to overfishing and plastic pollution, the Mekong River Basin has been damaged by upstream dams and climate change, which has had a significant impact on water levels in the endangered catfish habitat.

According to WWF, threats to the Mekong giant catfish include infrastructure development such as dams that block migration routes.

“Without being able to move up and down rivers, fish have few opportunities to reproduce,” said WWF.

Cambodia has imposed strict restrictions on fishing in the main river to try to reduce the number of endangered species killed in nets.

Numbers of Irrawaddy dolphins — which once swam in much of the mighty Mekong — have dwindled despite conservation efforts.

In 2022, Cambodian fishermen were shocked when they caught a giant endangered stingray that was four meters (13 feet) long and weighed 180 kilograms.

Over the past 25 years, CFA and researchers have tagged and released 100 giant catfish as part of a conservation program that encourages anglers to report catches of rare species.

Conservationists say the recent catch of giant catfish marks “a new era of conservation” and “new hope for the survival of species that have become increasingly rare in many of their habitats”.

Agence France-Presse contributed to this report.