One Fish, Two Fish, Sturddlefish

Guest News Brief  by Kip Hansen – 27 July 2020

featured_image_sturddlefish
featured_image_sturddlefish

What is a struddlefish when it wakes up in the morning?  A creature created by a mistake in a Hungarian fish breeding lab.

Yes, this story reads a little bit like a horror story, perhaps by the ghost of Michael Crichton.  The story deals with two fishes that are considered, by some, to be “dinosaurs”.

The story ( for example: here and here) comes from  a fish breeding lab in Hungary.

Habitat loss, overfishing and pollution have taken a heavy toll on paddlefish and sturgeon over the last century, which is why Attila Mozsár, a senior research fellow at the Research Institute for Fisheries and Aquaculture in Hungary and a co-author of the study, and others have been trying to breed both fish in captivity.

Last year, researchers were trying to induce gynogenesis, a form of asexual production that requires the presence of sperm, but not the actual contribution of their DNA, in Russian sturgeon.

Something unexpected happened: The paddlefish sperm the researchers were using successfully fertilized the sturgeon eggs.

“We never wanted to play around with hybridization. It was absolutely unintentional,” said Dr. Mozsár.

The paddlefish is said to be a primitive fish “because they have evolved with few morphological changes since the earliest fossil records of the Early Cretaceous, 120 to 125 million years ago.”  Sturgeon is also an ancient fish: “The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fishes who date back to the Triassic period some 245 to 208 million years ago.”  [both quotes from their Wiki entries]  The interest in sturgeon may stem from the fact that “sturgeon fisheries are of great value, primarily as a source for caviar, but also for flesh. Several species of sturgeon are harvested for their roe which is processed into caviar—a luxury food and the reason why caviar-producing sturgeons are among the most valuable and endangered of all wildlife resources.” [various Wiki]

For those piscephiles reading here, the study is “Hybridization of Russian Sturgeon (Acipenser gueldenstaedtii, Brandt and Ratzeberg, 1833) and American Paddlefish (Polyodon spathula, Walbaum 1792) and Evaluation of Their Progeny” [Open Access here]

It has not yet been determined whether or not the hybrid offspring are fertile and can reproduce, but it is reported that the researchers “assume these fish are sterile”.    This incident is another blow to Biology’s most commonly used definition of a “species”.  Paddlefish and sturgeon are not even in the same taxonomic Family , are not in the same Genus, and are not at all  closely related species.

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Author’s Comment:

Those interested in the Species Problem can read my earlier essay “Darwin — We’ve Got a Problem”.

Curious things happen when mankind gets to involving itself in the world of Nature. Share your favorite anecdotes along these lines in the comments.

Read widely, think for yourself and think critically.

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July 27, 2020 at 12:53PM