‘Mega’ creature — thought to be extinct — rediscovered in East Asia river. See it
In the early 1990s, scientists fished the Mekong River on the hunt for a massive fish.
The species was known by local fishers, but it wasn’t until 1991 that it was formally described in the scientific record.
Aaptosyax grypus, or the giant salmon carp, could reach more than 60 pounds and was identifiable from its “s-bend”-shaped jaws and fatty eyelid, according to a study published Oct. 7 in the peer-reviewed journal Biological Conservation.
The fish lived in the river that runs from Thailand and Laos into Cambodia, researchers said, as well as some of the Mekong River’s tributaries.
“Still, observations remain rare, with no more than 20 observations of the species since the species description in 1991,” researchers said.
Sightings of the “mega fish” species continued to decline, with only three reported in the early 2000s, according to the study.
“It (was) also considered to be one of the most threatened species in the Mekong River and is listed as critically endangered on the (International Union for Conservation of Nature’s) Red List,” researchers said.
Then, in 2005, the fish disappeared.
For 15 years the species was “suspected to be extinct,” according to the study, until a few landed in the hands of local fishers between 2020 and 2023.
“The specimens captured in 2022 and 2023 were adults (body mass of about 13 pounds and 11 pounds with a total length of 35 inches and 28 inches, respectively), leaving no doubt about the species identification,” researchers said.
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The findings “thus confirm the persistence of the species,” according to the study, but also raise questions about how to protect it.
“The scarcity of A. grypus occurrences, as well as the general lack of knowledge on the species’ habitats and ecology, make it difficult to set specific conservation actions,” researchers said.
The fish were found in their original habitat, the Mekong River, but over a much larger area, extending further into Cambodia than they had been historically known to go, according to the study.
Researchers believe by recruiting the help of the fishers who frequent the river and its tributaries, they can get a better understanding of the giant salmon carp’s population.
“A. cyprus, a top-predator fish, might, despite its rarity, have an important contribution to the Mekong food web by contributing to the top-down regulation of the trophic cascade,” researchers said. “We, therefore, appeal for conservation actions to ensure the sustainability of the rare and elusive A. grypus in the Mekong River system.”
The Mekong River runs for about 2,700 miles from southeastern China, along the border between Thailand and Laos, through Cambodia and Vietnam, and into the South China Sea.
This story was originally published October 25, 2024 at 12:42 PM with the headline "‘Mega’ creature — thought to be extinct — rediscovered in East Asia river. See it."
