No one saw a Mekong giant salmon carp for 15 years, but then the species was spotted in areas of Cambodia that suggest it may be found in more locations.
The Mekong giant salmon carp is four feet long and weighs 66 pounds. It is so elusive — recorded only 30 times by scientists — that they nicknamed it the “Mekong ghost” for the Southeast Asian river that was its habitat.
The evolutionarily distinct carp species, which is not a salmon, but has a salmonlike appearance, had not in fact been spotted by anyone since 2005. Researchers feared it had gone extinct.
But one man kept looking: Chan Sokheng, who had a nearly 30-year career in the Fisheries Administration in Cambodia, and died last year. In 2020, according to conservation colleagues he worked with, he received the call he had been hoping for: A fisherman in northern Cambodia had captured a fish with a sleek silver back, a bolt of yellow across its eye and a pronounced curved jaw: It was the Mekong ghost.
That fish was sold to traders in Vietnam, but other fishermen in the same part of the country reported their own sightings in 2022 and 2023. Mr. Sokheng was able to collect those two animals for study, which were found farther downstream in the Mekong watershed than the salmon carp had ever been discovered before, according to a paper published last month in the journal Biological Conservation informed by Mr. Sokheng’s work that announced the species’ rediscovery.
“It was his dream to see that fish, and his dream came true,” said Zeb Hogan, an aquatic ecologist at the University of Nevada, Reno, and an author of the paper.
The news of the Mekong giant carp’s survival has become “a call to action” for the fishery conservation community in Cambodia and greater Southeast Asia to begin efforts to find and protect the species, he added.