Recently, six critically endangered Mekong giant catfish were captured and subsequently released in Cambodia, raising optimism for the future of this remarkable species.
These aquatic behemoths can reach lengths of up to 10 feet (3 meters) and can weigh as much as 300 kilograms (661 pounds), comparable to the weight of a grand piano. Once, they thrived throughout the entirety of the Mekong River, which stretches 4,900 kilometers (3,044 miles) from its mouth in Vietnam to its upstream regions in China’s Yunnan province.
However, the population of these fish has dramatically decreased by 80% in recent decades due to severe overfishing, the construction of dams obstructing their migratory spawning routes, and other ecological disturbances.
Seldom do the millions of individuals who rely on the Mekong for their livelihood encounter a giant catfish. The recent capture of six of these fish within just five days is an extraordinary event.
The first two were located in the Tonle Sap River, a Mekong tributary close to the Cambodian capital of Phnom Penh. After being tagged, these fish were released back into the waters. On a following Tuesday, fishermen managed to capture an additional four giant catfish, two of which exceeded 2 meters (6.5 feet) and weighed 120 kilograms and 131 kilograms (264 pounds and 288 pounds), respectively. These fish are thought to have been migrating from their floodplain habitats adjacent to Cambodia’s Tonle Sap Lake, moving northward along the Mekong River, possibly heading towards spawning grounds located in northern Cambodia, Laos, or Thailand.
Dr. Zeb Hogan, a research biologist from the University of Nevada Reno who leads the U.S. Agency for International Development-funded Wonders of the Mekong project, stated, “It’s a promising indication that the species is not facing imminent extinction in the near future, allowing conservation measures time to take effect and steer the population away from decline toward recovery.”
Although much remains elusive about this giant fish species, a collaboration between the Wonders of the Mekong and the Cambodian Fisheries Administration has allowed for the capture, tagging, and release of approximately 100 Mekong giant catfish over the past twenty years. This initiative has provided crucial information about their migratory patterns, habitats, and overall species health.
“This knowledge is essential for creating migration pathways and protecting habitats, which is vital for future survival of these fish,” Hogan added.
The Mekong giant catfish holds significant importance in the region’s culture, represented in ancient cave paintings that date back 3,000 years, revered in local legends, and regarded as an emblem of the river’s ecosystem, which supports millions of lives and contributes $10 billion annually in fishery value.
The active participation of local communities is key to ongoing conservation efforts. Fishermen have become more aware of the necessity to report any accidental catches of rare and endangered species to authorities, enabling researchers to assess these fish, tag them, and later release them.
“Their collaboration is vital for our research and conservation endeavors,” stated Heng Kong, director of Cambodia’s Inland Fisheries Research and Development Institute.
In addition to the Mekong giant catfish, the river also hosts other large species such as the salmon carp, which was once thought to be extinct until it was spotted earlier this year, and the giant sting ray.
The singular feat of catching and tagging four of these fish in one day is likely the “big fish story of the century for the Mekong,” according to Brian Eyler, director of the Stimson Center’s Southeast Asia Program in Washington. He suggested that such occurrences corroborate the resilience of the annual fish migration, despite environmental pressures along the Mekong.
“We hope that what occurred this week highlights to both the Mekong nations and the global community that the diverse fish population of the Mekong is notably unique and warrants conservation,” he remarked.