Steelhead are Now Classified as Salmon?- Why?

Discussion in 'Steelhead' started by pilchuck steelie, Mar 18, 2008.

  1. ChrisW

    ChrisW AKA Beadhead

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    Nice thoughts but steelhead were reclassified long before they were seriously considered for ESA listing.

    Another and perhaps more accurate way of looking at it is that rainbows are steelhead that have become residualized either for man made reasons (dams, lakes) or for natural reasons (such as rich food sources in a river that is a long distance from or has difficult access to the sea). By and large if the steelhead/rainbows have access to the sea they will exhibit anadromous life histories. Nothing is absolute with these fish however.
     
  2. ak_powder_monkey

    ak_powder_monkey Proud to Be Alaskan

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    I'm no taxonimist but I think fish that die after they spawn should be in a different genus than fish that don't... But what do I know.
     
  3. Richard Olmstead

    Richard Olmstead BigDog

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    Many steelhead die after they spawn. Would you sort out those that die and put them in one genus and those that return to the sea and put them in another genus?

    I don't ask this to pick on you, but to make a point. For a long time, there was confusion resulting from an uncertain mix of functional attributes and physical attributes that were used as a basis for classification. It was Darwin who first suggested that all classification should be 'genealogical' (we use a different term, 'phylogenetic' today). For the past 150 years taxonomists have been trying to conform classifications to phylogeny, thus many changes along the way as our understanding of biology and evolution improved. Dramatic improvements have come on the past few decades with genetic methods of inferring evolutionary relationship. The evidence now is clear that rainbow/steelhead and cutthroat trout are related to Pacific Salmon, hence their classification together in the genus Onchorhynchus.

    That being said, the 'rank' (e.g., genus, family, etc.) to which a group of species is assigned still is a subjective and arbitrary decision. Current efforts to do away with the arbitrariness of ranks and provide a stable system of naming taxa (a general term for those groups of related species we might want to assign a name to) are underway and may supplant our traditional system at some point.

    D
     
  4. ak_powder_monkey

    ak_powder_monkey Proud to Be Alaskan

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    No because all pacific salmon die after they spawn 100% of the time. I understand that cutts, bows and salmon are closely related genetically but the differences in their life history should warrent cutts and bows their own genus IMO. I'd assume the highest adult mortality rate of any fish species is after spawning however however some survive, with pacific salmon NONE survive. Of course they shouldn't be classified in Salmo but I think rainbows, cutts, and other trout in Onchorhynchus should be in a different genus. Oh and bows and Cutts are the same species, Cuttbows can produce offspring right?
     
  5. Preston

    Preston Active Member

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    No, cutthroat and rainbow/steelhead are not the same species even though they can hybridize. There are significant, consistent physical differences between the two. Hybridization is relatively rare among coastal cutthroat (Oncorhynchus clarki clarki) and coastal rainbows (O. mykiss irideus) and even among westslope cutts and (O. clarki lewisi) and redband rainbows (O. mykiss gairdneri) in the regions where they co-evolved. It is most common among geographically isolated cutthroat subspecies subsequent to the introduction of planted rainbow stocks.

    As I mentioned above, small numbers of the Japanese cherry salmon (O. masou) can survive spawning and I see no reason why mortality (or the lack thereof) after spawning would not represent a spectrum of strategies evolved by varied species within a single genus.
     
  6. Paul Huffman

    Paul Huffman Lagging economic indicator

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    Linnaeus started it, not Darwin.

    A classification that included species that died after spawning could include smelt, eels, lamprey, Pacific Salmon, squid, and octopi. The classification that includes species that spawn multiple times could include steelhead, walleye, shad, carp, bass, and hopefully humans.

    What a nightmare to have WDFW manage my spawning!
     
  7. Richard Olmstead

    Richard Olmstead BigDog

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    Linnaeus didn't have any understanding of evolution, thus his classification did not try to be 'genealogical.' Darwin was the first person to recognize that all living things are related through common ancestry and, thus, argued that classifications should not be artificial systems based on some arbitrary characteristics (as Linnaeus' classification was), but rather should be based on recency of common ancestry.

    As for the start of classification in western thought, most trace its roots to Aristotle, but humans had been classifying living things in folk taxonomies much earlier than that. Linnaeus developed a 'system' and adopted some conventions in nomenclature that have survived to the present, thus the credit he gets for starting our modern taxonomic system. But, beware making too strong an argument for Linnaeus if there are any fish taxonomists present, as there may well be on this board, because his contemporary, Artedi, who died young and left his writings on fish taxonomy to Linnaeus, may really have developed some of the ideas Linnaeus takes credit for).

    Dick, the taxonomy professor
     
  8. Paul Huffman

    Paul Huffman Lagging economic indicator

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    Thanks for clarifying this, Prof. Olmstead.

    I recently married into a Swedish family. When visiting the old country, I found that the Swedes treated Linnaeus as a national hero. Didn't hear much about Artedi, even at the Gothenburg Aquarium, although he is another deserving Swede.

    Artedi drowned in Amsterdam while working on a the collections of Albertus Seba, which lead George Shaw to place this poem on his grave:


    In humulum Artedi:

    Here lies poor Artedi, in foreign land pyx'd
    Not a man nor a fish, but something betwixt,
    Not a man, for his life among fishes he past,
    Not a fish, for he perished by water at last.
     
  9. Richard Olmstead

    Richard Olmstead BigDog

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    Fun poem, Paul. Thanks.

    Artedi was Linnaeus' classmate as an undergrad at the University of Uppsala. Artedi was 2 years Linnaeus' superior and encouraged Linnaeus to think about classification. They became close friends and shared a lot of ideas. They agreed to a pact that if either of them came to an untimely death, the other would publish their findings posthumously.

    Artedi found a benefactor in Amsterdam to work for, as was the practice of the day for natural historians. Linnaeus followed him to Amsterdam after finishing his schooling in Sweden. When Artedi died (drowned in a canal, as you say, and as was quite common in the day in Amsterdam), he had finished his magnus opus on fish classification, but had not been able to afford to publish it. At significant personal expense, Linnaeus paid off all of Artedi's debts to his landlord in order to obtain his manuscript on fishes to publish it as he had promised his friend.

    At this point, Linnaeus had yet to publish anything. Linnaeus did publish Artedi's work, but only several years later, after publishing a series of his own works that were not yet written at the time of Artedi's death and in which Linnaeus lays out much of his 'system' for classification (not including the binomial nomenclature, for which he is most well known today, which came somewhat later). Scholars have pointed out since then that most of Linnaeus's 'system' for which he gained so much fame in his own day and since, follow Artedi's 'system' for classifying fishes. Of course, many of those 'scholars' happen to be Ichthyologists! If true, and I have every reason to believe it is true, then Artedi deserves to share at least part of the renown that Linnaeus accepted for himself. Most stop short of suggesting Linnaeus had anything to do with Artedi's death, although ...

    By no means do I want to take away from Linnaeus's tremendous contributions, which in large part consisted of promoting a system of classification to the rest of the scientific world into which people could insert their own findings, thus making the science of taxonomy a global endeavor.

    Now, where did this thread start?

    Dick