RUSSIAN STURGEON. ZOCHA_K, GETTY IMAGES
Both fish—which are considered endangered—managed to breed in an unexpected way while in captivity at a Hungarian lab.
“We never wanted to play around with hybridization. It was absolutely unintentional,” Attila Mozsár, a senior researcher at the Research Institute for Fisheries and Aquaculture in Hungary, told The New York Times.
Sperm and eggs from the fish ended up creating hundreds of hybrid offspring, but some have since died. According to the researchers, “survival in all hybrid family groups ranged from 62 percent to 74 percent 30 days after hatching.” This also marks the first time that successful hybridization has occurred between both species.
This new sturddlefish came into existence when the research team tried to breed more Russian sturgeons via gynogenesis, a type of asexual reproduction in which sperm is necessary but leaves no traces of its DNA behind. As a result, the offspring ends up with 100 percent maternal DNA (and none from the paternal contributor.)
This is where the American paddlefish comes into as the team used sperm from this fish to start the gynogenesis in the sturgeon. What researchers were not expecting was that the sperm and egg would fuse creating a new hybrid fish. Still, the hybrids aren’t all the same; some are close to an even 50/50 genetic split between their two parents, but others appear more sturgeon-like while others have stronger paddlefish traits. According to Live Science, all of the hybrids are carnivorous just like the sturgeon who feeds on mollusks and crustaceans. This is unlike the paternal paddlefish who feed on various zooplankton.
The Times reports that approximately 100 sturddlefish remain alive today. The team behind the accidental hybridization says that they have no plans for creating more sturddlefish in the future—a short-lived life for a species that was never meant to be.