They were trying to save a species. Instead, they created a fish that is part sturgeon, part oar fish, all accidents

But its accidental hybrid, a fish that is partly American spoonbill and partly Russian sturgeon, could benefit fish farming and the industry’s carbon footprint. And by themselves, fish are a wonder of biology.

The “sturddlefish” study appeared this month in the scientific journal Genes.

As a step

The initial objective of the study was to encourage the critically endangered sturgeon to reproduce asexually. This is not exactly how it was.

The Russian sturgeon, on the other hand, hybridized with the American spoonbill fish, the first time the two successfully hybridized in captivity. The oarfish originally intended to provide sperm, not its DNA, to help the sturgeon reproduce by itself.

But they weren’t supposed to hybridize. Previous attempts at hybridization between the American spoonbill and other sturgeons had failed, the authors wrote. And because of their evolutionary similarities, the two have vastly different feeding habits, preferred habitats, and physical characteristics.

Furthermore, the two fish would never have met naturally. The American spoonbill fish inhabits the Mississippi River basin, and the Russian sturgeon inhabits the Russian rivers. The Russian sturgeon is considered extremely valuable for its roe or eggs. Both species are threatened by declining habitats and overfishing.

While the caviar that comes from sturgeons is a delicacy, fish themselves are extremely rare in Russian waters. That’s why the researchers, all from Hungary, wanted to encourage the sturgeon to reproduce through gynegenesis, which uses treated sperm from another species to convince the specimen’s eggs to develop.

But in gynegenesis, the DNA from the sperm sample is not supposed to be transferred to the offspring.

What could hybrids do next?

There were two types of hybrid fish: one of them is one part rowing fish, two parts sturgeon, and the other is one part rowing fish, four parts sturgeon. Most of them, between 62% to 74%, survived one month after hatching.

Both hybrids resembled sturgeon, with their striated back and short nose, although one of them had a more pointed snout that resembled their father oarfish.

“The how and the why remain open questions,” said lead author Jenő Káldy, an aquaculture researcher at the Fisheries and Aquaculture Research Institute of the Hungarian National Center for Agricultural Research and Innovation. The two probably hybridized because the sturgeon slowly evolved. This means that there are probably fewer differences between their morphology and genes and those of other species, including, apparently, the American spoonbill.

Sturgeon hybrids are typically used in aquaculture and provide about 20% of the world’s production of caviar, the researchers said. But if hybrids adopt the habits of the parents of the oarfish and learn to feed on plankton and other microscopic organisms instead of the more demanding diet of crustacean sturgeon and larger meals, they can play “an important role in adapting the pond aquaculture to the challenges of climate change “. “the authors wrote.

Simply put, if these “sturddlefish” end up without being fed and can instead rely on natural plankton in their habitats, the carbon emissions that would have resulted from feeding them will be reduced. Along with their high market value, accidental hybrids could end up being more valuable than their creators imagined.

As for saving the endangered sturgeon, the study “has brought us closer to our goals,” Káldy said.

However, for now, the hybrids live peacefully in a research facility in Hungary, where there is no risk of invading non-native waters.