Fish species conservation efforts with distant relatives in Hungary: How do genes meet after 184 million years?

Aiming to conserve a living fossil species, the Russian sturgeon project of the Hungarian Fisheries Research Institute leads to new questions about nature protection and evolutionary biology.

Close-up pphoto of a Russian sturgeon, underwater
©Dan Kollman
A living fossil, the Russian sturgeon is endemic to the Danube river basin.

A research project lead by the Hungarian Fisheries Research Institute (NAIK-HAKI) with the aim of ensuring the conservation of the Russian sturgeon in the Danube and its tributaries is one of the flagship efforts of Hungarian fish species conservation: to protect and enhance the reproduction of one of the noble living fossil fish species, exclusively for conservation purposes.

The Russian sturgeon, alongside with the other three Ponto-Caspian sturgeon species (starry sturgeon, bastard sturgeon and beluga) and the more common sterlet are native to the wider Danube Basin, hence the Carpathian Basin: a land gifted with a dense network of lakes and rivers. The Russian sturgeon alongside its relatives has been thriving for millennia but have been facing severe decline due to habitat loss, river regulations and pollution since the 20th century. In Hungary, the Russian sturgeon is one of the most endangered species among these mysterious living fossil creatures.

Picture of a Russian sturgeon fish, swimming in shallow water, its back breaking the surface
©Bas Kers
The conservation effort if the Russian sturgeon is a flagship project at the Hungarian Fisheries Research Institute.

The Hungarian Fisheries Research Institute focuses on its conservation by regulated reproduction such as induced gynogenesis which –in this case – involved the fertilization of female Russian sturgeon eggs with the milt of male American paddlefish. As planned, the researchers successfully created the offspring, however, to much of their surprise, the new creatures are still alive and in good condition even after a month. This case sets precedents to many questions of evolutionary biology: How is it that two distinct species were able to create viable offspring? It is still not known whether the hybrid fish could recreate. They are kept in a closed and controlled facility.

The Russian sturgeon and the American paddlefish have been evolving separately (on two separate continents) for 184 million years, yet most of their hybrid offspring hatched and live successfully. This example could be fertile ground for evolutionary biology and genetics research, where answers for the many questions lie in the geologically ancient story of the Acipenseridae fishes.

D.K.

Sources:

Annie Roth: Scientists Accidentally Bred the Fish Version of a Liger In: The New York Times, July 15, 2020.  

A magyar kutatók halgenetikában elért új eredményeire a New York Times is felfigyelt. Hungarian Fisheries Research Institute (NAIK-HAKI), July 20, 2020. (Hungarian language site)

Photo credit:
Cover: Russischer Stör by Dako99, via Wikimedia Commons
Acipenser gueldenstaedtii (Russian sturgeon / Russische steur) by Bas Kers, via Flickr.