The news of the Mekong giant carp’s survival has become “a call to action” for the fishery conservation community in Cambodia and greater South-east Asia to begin efforts to find and protect the species, he added.
“We’ve only ever seen this fish in field guides,” said Mr Heng Kong, director of the Inland Fisheries Research and Development Institute and an author of the study. “We’d like to identify areas where this species is still present, and then work with local communities to get their strong participation in conservation.”
Originating in China and winding through 2,700 miles (4,345km) of South-east Asia, the Mekong River is the world’s third most biodiverse waterway. But like many other freshwater ecosystems, it faces myriad threats, like upriver dams in China, Thailand and Laos as well as overfishing and pollution.
The WWF estimates that 19 per cent of more than 1,100 fish species in the Mekong River are endangered.
Had the Mekong giant salmon carp gone extinct, it would have been the first of the river’s dozen-plus species of megafish – those that weigh over 30kg – to succumb to that fate.
With its rediscovery, it is now considered to be the river’s most endangered fish.
Because the Mekong giant salmon carp was thought to be extinct, it had not been listed as a protected species in Cambodia or known widely among fishermen.
“Most Cambodians have never even seen or heard about this fish species,” said Mr Chhut Chheana, an author of the study and outreach coordinator at Wonders of the Mekong, a project backed by the US Agency for International Development that aims to maintain the ecological, cultural and economic integrity of the lower Mekong River.
After the salmon carp’s rediscovery, Mr Kong added it to the country’s protected species list.
But legal protections will be effective, he said, only with buy-in from Cambodia’s fishing communities.
“We have our fishery law, but we understand that we need to establish good collaborations with fishermen,” Mr Kong said.
The reemergence of the Mekong giant salmon carp serves as a symbol of the “vast and threatened freshwater fish diversity” of the Mekong River as a whole and of the urgent need for protections, said Ms Michele Thieme, deputy director for freshwater at WWF-US, who is not involved in the project.
The salmon carp was rediscovered in Stung Treng province, in the main stem of the Mekong River and in one of its major tributaries.
These sites are farther south than where the fish was historically known to occur. Its discovery in these places suggests that the species’ range might be bigger than scientists previously thought.
The question, now, is whether Cambodia represents “the last hope” for the species, Mr Hogan said, or whether the salmon carp, which is migratory, persists in other places. Mr Hogan thinks there is a high likelihood that it does.
He and his colleagues are organizing a search across Cambodia, Laos and Thailand for surviving populations. Their efforts will include conducting environmental DNA surveys to detect evidence of the species in water samples.
“We’re going to have teams going out to look for this fish in a more serious way than ever before,” Mr Hogan said. “It wouldn’t surprise me if we found fish in all three countries.” NYT
