One Fish, Two Fish, Sturddlefish

Guest News Brief  by Kip Hansen – 27 July 2020


What is a sturddlefish 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”.

[Originally, sturddlefish in the first paragraph was mis-typed struddlefish — its near homophone — resulting in several hilarious comments. — kh )

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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85 thoughts on “One Fish, Two Fish, Sturddlefish

  1. Q What do you get if you cross a climate activist with a vegan cyclist?

    A Someone everyone can hate.

  2. It goes without saying that they’re in different genera, if in different families. However the families of sturgeon and paddlefish are closely related within the same order. If their hybrids are indeed fertile, then the families should be unified. Linnaean taxonomic classification is not as rigorous as cladistic phylogeny.

    This result is actually not too surprising when you consider that both sturgeon and paddlefish have a very large number of chromosomes, about half of which are microchromosomes. The order can be divided into two groups: the first (eg. paddlefish) with a chromosome number of ~120, and the second (at least some sturgeons) with 240–250 (but see below for even higher).

    Paddlefish chromosomes can arranged into 30 quartets, suggesting that they’re tetraploid. Which would make sturgeons octoploid!

    “The average chromosome number of the North American white sturgeon, Acipenser transmontanus…, was found to be 271 ± 2.5 (ranging from 265 to 276)…A representative karyotype…consist(s) of 132 meta- and submetacentric chromosomes, 44 acrocentric chromosomes and 98 microchromosomes.”

    Whole genome duplication on overdrive!

    But then there are lungfish, another “primitive” group, and the closest living fishy relatives of us tetrapods. All extant lungfish have very large genomes. The smallest is Neoceratodus forsteri’s (Australian lungfish), with a haploid genome of 50,000 Mb. The largest is the enormous 130,000 Mb genome of the African Protopterus aethiopicus (Marbled lungfish). The latter has relatives in South America.

    • John ==> Thanks for the schooling on the genetic details of the Struddlefish.

      I am not sure one can say this: “However the families of sturgeon and paddlefish are closely related within the same order.”

      ORDER — is a pretty big category in Linnaean taxonomic classification. For instance Primates includes humans down to the mouse lemur. Carnivora include
      s the cats, the dogs, bears and walruses!

      We would be rather surprised by a walrus and dog hybrid! Or even a cat-dog hybrid.

      Still, the whole thing is interesting — mostly, to me, from the anti-Darwinian viewpoint about the preciousness of “species”.

      • Their families are closely related within the order, as for instance are the families Hylobatidae (lesser apes) and Hominidae (great apes, including humans), comprising Superfamily Hominoidea (apes) in Parvorder Catarrhini (apes and Old World monkeys) in Infraorder Simiiformes (apes, OW and New World monkeys) in Suborder Haplorhini (apes, “monkeys” and tarsiers) within Order Primates. The sister suborder to Haplorhini, Strepsirrhini, contains lemurs and lorises. Plus, there are extinct groups.

        Similar closer subgroupings exist within the sturgeon-paddlefish-shovelnose Order Acipenseriformes, which ancient lineage is now reduced to only two living families.

      • But there is a great deal of hybridization within the canid side of Carnivora. That’s the point.

          • Yes, putative speciation can indeed be reversed, as long as the suppressed genes are still functional. Many species are far from immutable.

            I was hoping that Trump would shut down the USFWS’ brain dead “red wolf” program, which breeds and releases into NC large coyotes from TX.

          • The wolf-like canids all have 78 chromosomes (39 pairs). Chromosomes of the species in this group are karyologically indistinguishable from each other. It includes, in genus Canis: the gray wolf (C. lupus), domestic dog (C. lupus familiaris), dingo (C. lupus dingo), coyote (C. latrans), golden jackal (C. aureus) and Ethiopian wolf (C. simensis). In two other genera are the dhole (Cuon alpinus) and African wild dog (Lycaon pictus). Members of Canis and Cuon can potentially interbreed, except probably for the black-backed (C. mesomelas) and side-striped (C. adustus) jackals, which have 74 chromosomes.

            The African wild dog theoretically could too, but doesn’t appear to interbreed with other members of the group. A 2018 study suggests that it did hybridize with dholes (wild dogs of Central, South, East and Southeast Asia) in the past, when their ranges might have overlapped.

            Interspecific Gene Flow Shaped the Evolution of the Genus Canis


      • “We would be rather surprised by a walrus and dog hybrid! Or even a cat-dog hybrid.”

        If they’re in love, it shouldn’t matter to us. They should be allowed to get married in all 57 states.

      • I’d go with “anti-biology” rather than “anti-Darwin”. He didn’t define “species” in “On the Origin of Species”. He recognized that species are mutable, even if he didn’t know how mutation works. Further observations since his time have shown this understanding to be the case. The sciences of biology, biochemistry and molecular biology are based upon the reality of his insight, now simply a repeated observation of nature.

        • Tierney ==> Actually I have. My comment is in reference to the attempts by humans to preserve “species” that are not species (such as the Red Wolf) which was fading out due to shifts in the local mix of wolves and coyotes and to the worries expressed in the paper and news article on Speciation Reversal which implied that we might have to do something to prevent such to “preserve species” — both efforts nonsensical for those that think Darwinian evolution should be allowed to reign.

          But thanks for joining the conversation. Reading the linked material allows you to keep up with what is being talked about.

      • “I am not sure one can say this: “However the families of sturgeon and paddlefish are closely related within the same order.””

        Madonna would disagree, having made a fortune with her song about the paddlefish: “Like a sturgeon.”

        • Michael ==> LOL . . . . my intention for this essay, that is supply some comic relief to the constant drum beat of gloom and doom, has been fulfilled. Thanks for helping!

    • According to the taxonomy rule you propose, we need to be unified with Suidae.

      Aves must be unified with Mammalia because of platypus.

      Close genomic similarity can help hybridization, but it is not a requirement. A hard limit on phylogenetic distance beyond which hybridization is impossible does not exist. As long as critters are in love and keep trying, it will continue to happen.

      Plants hybridize pretty much any-to-any, no matter the distance. It is not as unusual for birds and fish to form distant hybrids as it is for mammals, but there is no law that says mammals are not allowed to hybridize.

      You might find this opus entertaining:

  3. The American paddle fish and the American sturgeon both exist in the same water here in the US. That hybrid looks a lot like a Shovelnose Sturgeon.

        • Yes. It’s possible to reconstruct evolutionary history by looking at chromosomes without even sequencing genomes. Human chromosome #2 is a good example.

          That these fish have so many chromosomes should make hybridization easier between more distantly related groups. With many duplications, there is a higher likelihood of genetic sequences finding a partner with which to line up.

    • Mark ==> Not all the resultant hybrids look identical — see the paper and some of the press photos.

  4. As it’s a) Hungary and b) bonkers, I absolutely believe it. I live here, and could tell you stories of Hungarians that would keep you awake at night. We live quite close to the Tisza, which used to have sturgeon, till they fished them all out. They were surprised to learn that the lake and river did not, as they assumed, contain infinite fish. And of course, they blamed the gypsies.
    In the Hungarian mind, this new fish will elicit two questions:
    1: Can I make soup from it, and
    2: How much is it worth?

    • Adrian Mann ==> Thanks for the Hungarian Viewpoint.

      I believe that one can make Struddlefish Soup! whether they are of any monetary value is not known.

      • In Hungary, you can make soup out of anything. Many’s the time we’ve been invited to dinner, only to be presented with a bowl of liquid with various dubious looking animal parts floating in it…
        In Hungary, everything is of monetary value! Things that have no monetary value are of no importance and may be disregarded.
        When Enrico Fermi asked “Where are the aliens?”, Leo Szilard (Hungarian) replied “They are among us, but they call themselves Hungarians.”
        He was right.

      • Pastry is a better use for Struddlefish.

        Sturddlefish are better for soup. They stur & spoon well.

  5. According to Monthy Python fish are at the centre of the meaning of life. What did they know then which we didn’t?

    • Dr. Crockford ==> Thanks for stopping by — I thought it was worth mentioning, even if just for the comic relief aspect!

  6. Too many genetic acronyms, looks like female dominance for hybrids. Might check and see if they jump, paddlefish don’t apparently, at least some sturgeon do, dangerous, reason(s) unknown. Sturgeon are usually the biggest fish around. Lots of fish jump, even guppies, while not being chased, lots more oxygen in the air, but probably would get more stroke looking at carbon dioxide excretion. Don’t claim ridding of parasites, an insult to their tenacity.

    “A total of 2,329 commercial sturgeon farms were recorded by 2017 globally, which represented an increase by 7% compared to 2016. Of these farms 54% were located in China, followed by Russia (24%), the Middle East (8%), the Far East (7%) and Europe (6%).” I lost the reference, think it was in the Journal of Applied Ecology, had a sturgeon conference about a decade ago in Wuhan.

    • HD ==> Fascinating {?}…..I am surprised to hear that therew are so many sturgeon fish farms….

    • Once had the splendid experience while sailing across San Pablo Bay (north arm San Francisco Bay) of being surrounded by jumping sturgeon. Dozens of them, many 6 foot or better monsters, hurtling straight up then crashing back, apparently over and over since it went on for at least ten minutes. As far as we could see, the highest jumps did not quite get the fins clear of the water- leaving just the last of the fins barely awash. Words fail.

      • That would be an awesome experience!

        Growing up, we fished the Columbia River quite often and we would fish below Bonneville Dam in the late spring and early summer during the shad run. We would catch the shad and use them for bait to try and catch monster sturgeon. At times, you would bait up, cast and not one minute later you would get nailed and have a fish on the end of the line. Using shad was almost a guarantee to not catch any fish less than three feet in length and the best part of the shad for bait?…Were the gills. The real challenge was getting the ones over six feet to shore. In all my years of fishing this way, I only managed to land one fish over six feet and it measured just over seven feet and then was quickly released. Truly amazing animals!

        While we would fish for the shad or wait for a sturgeon to bite, you would often see these huge fish lunge out of the water and sometimes even completely clear the water surface! It was amazing to see. You would also see them mere feet from shore cruising slowly up or down the bank looking for shad to chase and consume. We all thought they were bottom feeders but that isn’t the case. They love eating those shad and chase them vigorously.

        Those were the days of growing up in Vancouver, Washington and enjoying the many natural and wonderful exploits of the area. I do miss it sometimes and hope to one day take my kids back there and take them fishing on that mighty river…Even if we don’t fish for sturgeon.

  7. The Struddelfish is two delectable foods in one, being part layered flaky sweet pastry and part fish.

  8. 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”.

    Considering that this was something that it was assumed wouldn’t happen in the first place, I’m not placing a lot of confidence in their assumptions.

    • fred ==> Yes, Bruce too, who said “The Struddelfish is two delectable foods in one, being part layered flaky sweet pastry and part fish.”

  9. Also just before the soviet break-up scientist in Russia were said to have been working on cross-breeding fish and made a new species ‘accidentally’. Later reports said that this cross-breeding experiment also had some ‘human DNA contamination’. All evidence of experiment was covered up, and ‘officially’ all samples were said to have been destroyed. However in the late 1990s some anonymous scientist leaked that they “all escaped into the wild when they were flushed down …”[transmission ended abruptly.]
    It is understood the experiment was said to involve crossing the Hagfish (of the class Myxini also known as Hyperotreti), with a bony-eared assfish (Acanthonus armatus — see but was contaminated with some human DNA.
    It is said they managed to make a very small brained species that swam poorly while continuously exuded green slime while endlessly repeating emotive news memes, and the scientists involved allegedly called it ‘My-Assxini MSM journalisti’.
    Many people have speculated that results of this experiment probably went mainstream and first became established at the BBC but since has infected all all major news networks worldwide.

  10. Caviar comes from virgin sturgeon;
    Virgin sturgeon’s a very fine dish.
    Very few sturgeon are ever virgin,
    That’s why caviar’s a very rare dish.

    Caviar comes from virgin sturgeon;
    Virgin sturgeon’s a very fine fish.
    Virgin sturgeon needs no urgin’;
    That’s why caviar is my dish.

  11. And the name of the guy there had to be “Attila” in Hungary.
    Bloody shite…


    • Very common name out here. Attila the Accountant? Quite normal!
      There’s a woman newsreader who’s name is “Boglarka”, I kid you not.

      • Well, I was going to link to Monty Python’s Attila the Hun show on Youtube, but you have to pay to watch.

  12. In the FWIW department, in my turf “UP North” we had a natural hybridization between the Chinook (aka King) Salmon and the Pink Salmon. The DNR in both Canada and the US dubbed it the Pinook. As an (mostly unsuccessful) angler I would love to have the Pinook established as a game fish. Michigan has stopped stocking Chinook Salmon because the ecosystem doesn’t provide enough bait/food fish right now. I’ve caught Chinooks that were 25+ pounds. Pinks come in at 1-2 pounds. The Pinooks that were studied came in at 7-10 pounds, well within the support capability of the Great Lake ecosystem, and would be a great game fish.

  13. Sturgeon is all catch and release on the mighty Fraser river in BC
    If you wish for the experience of holding on for dear life while hoping the 800lb sturgeon tires before he can strip the line or the guide can lift anchor to give chase that’s the place to go.

    If you fish, having one of these monsters breach the water completely while trying to spit the hook is a joyful experience

  14. Really interesting story. My quibble: calling a species “primitive” because it has survived relatively unchanged for millions of years is like calling a hockey team “unskilled” for having won the Stanley cup five years in a row. When nature finds a really good design it keeps it.

    • Biologists say “derived” instead of “advanced”, but they also know what they mean when using less precise terminology.

  15. The two most fruitful scientific insights from the 20th century – now shaping the whole future of humankind : Watson & Crick’s amazing discovery, the intricacies of which are still far from understood – and Quantum Theory, which our human mind cannot “understand” at all.

    • Andy ==> I understand that there is another layer of understanding altogether that is even deeper — but that involves what is known in our culture as religion.

  16. another blow to Biology’s most commonly used definition of a “species”.

    Maybe. Maybe not (if it’s a “mule”).
    Most of what passed for classification in XIX century was little more than herbarium arrangements with Latin labels, anyway.

    • TBeholder ==> Maybe so — but we do have a major branch of science with a major feature — species concept — that remains ill defined and controversial. A sword/concept that has entered in national and international law without being properly defined or understood.

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