This should settle it... Steelhead = Rainbows

Discussion in 'Steelhead' started by windtickler, Oct 20, 2006.

  1. TomB

    TomB Active Member

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    lets see to answer some comments/questions:

    steelhead and rainbow trout are different life history expressions of the same species. they are also members of the same genus (Oncorhynchus) that contains all species of pacific salmon as well as cutthroat trout- this genus is collectively known as the 'salmon' because the true 'trout' is refers to the genus salmo which contains atlantic salmon and brown trout.

    in order for a rainbow trout to use marine environments they must go through physiological changes which allow them to maintain biologically sustainable osmotic balance. this process has many constraints, chiefly temperature and size of fish, and is less common for o. mykiss above about 10 C and for older individuals.

    -T
     
  2. HauntedByWaters

    HauntedByWaters Active Member

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    I was under the impression that latitude has little to with it. Geography and chemistry surely matter more. I can see what these scientists meant as far as sunlight is concerned but it is far too general. Some rivers and lakes into the far north are fertile beyond belief even without anadromous fish. I was told that the latest science has the fish load linked directly to the presence of phosphites that are essential to the development of bugs and small crustaceans. This is why spring creeks and chalk streams are so full of bugs, because these essential minerals are present to an extreme. The same can be said for all rivers and lakes in some form or another.

    Also, I read a book years ago about the brown trout plants in Argentina and they were non-anadromous. Also, I have speant much time with a master guide on the Cowichan by the name of Iam Muirhead and he said that the browns there were non-anadromous as well. Anyway, I ain't trying to argue here just that I ain't talking out my anus. I have read all the books I can get my hands on and have researched all of this for most of my life.
     
  3. JRSly

    JRSly Oncorhynchus clarki clarki

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    There are a lot of things that I want to comment on in this post, but I don't really have the time right now. I do have two comments to be made.

    I like what Richard said about being in the same genus, then actually they are ‘salmon’ in a sense. Salmon and trout are just common names that we give to the fish. It used to be a life history kind of thing, but even that doesn’t really make much sense because there is Atlantic salmon, and there life history pattern is more similar to a steelheads, they don’t always die after they spawn. Steelhead/rainbows were just recently (1989) brought into the same genus as the Pacific salmon (Oncorhynchus) we have, before that they were known as Salmo gairdneri. So as you can see the whole taxonomic classifications are changing as well. Researchers have found that they are genetically closer to the Pacific salmon, so that is why they were brought over, same with cutthroat trout. I actually know quite a few fisheries biologist that think that the whole common name thing is just a joke, it doesn’t really have anything to do with anything, just what people originally thought was going on. Some of these are pushing for a common name change, so all Oncorhynchus species will be known as salmon, all Salmo will be trout, and all Salvelinus will be char. I think they have a good argument, but this would confuse a lot of people, then again, I know some people that still call rainbow/steelhead Salmo gairdneri until they realize it is now Oncorhynchus mykiss. If you think about it, things just really don’t make much sense if you try to make meaning of common names. Most of the things that are char, we call trout (brook, bull, lake). So I wouldn’t really get too hung up on it.

    My second comment is for windtickler, I think what you meant to say is the genus Oncorhynchus, not salmonoids.

    A good reference if you are interested in learning about this is Thomas Quinn's book The Behavior and Ecology of Pacific Salmon & Trout. For being a reference/textbook it is a really easy read, and pretty cheap. Quinn is a really knowledgeable guy, and it is a great book for anyone interested in salmon and trout. On a different note, you guys are on the surface of touching into my research topic for my thesis, but instead of looking at O. mykiss (rainbow/steelhead), I am looking at O. clarki clarki (coastal cutthroat/sea-run coastal cutthroat). If anyone is now interested in why SRC go to sea a good resource is an article by T.G. Northcote in the Sea-Run Cutthroat Trout Symposium from 1995. The article is titled Why Sea-Run? An Exploration into Migratory/Residency Spectrum of Coastal Cutthroat Trout.

    Sly
    (Hope this isn't to wordy)
     
  4. HauntedByWaters

    HauntedByWaters Active Member

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    That sounds good. How could I get it though?
     
  5. JRSly

    JRSly Oncorhynchus clarki clarki

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    I agree with most of what you said, but just because something hasn't been documented much, that doesn't necessarily make it true. It is kind of like saying a null hypothesis is true, when in reality all you can really say is that you didn’t reject it. It is believed that SRC don’t really use the open water like the rest of the genus Oncorhynchus, but then again, there have been some cases where SRC have been caught far off shore. I have read a couple papers from research done in California that have found SRC far off shore. It all kind of depends on the circumstances. SRC research is a pretty new thing, I mean some of the best stock information for SRC in Washington is from the Stilly, and that has only been going on for a couple years. Oh, and I am not arguing, I am actually agreeing with what you said, just wanted to make the one addition.

    Sly
     
  6. Paul Huffman

    Paul Huffman Driven by irrational exuberance.

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    I thought the interesting point of the article was underplayed like a buried lead: In the Kol, the majority of the population is resident, while in the more barren Utkholok, the majority are anadromous. At a conference on steelhead anadromy we held in Yakima two years ago, http://ykfp.org/steelheadworkshop/
    there seemed to be two competing ideas about the reasons for anadromy: 1.) Fry in severe freshwater habitats head to the ocean. 2.) Fry in favorable freshwater habitats grew quickly to a size that made anadromy a better option. I tend to believe 1. because of the examples I'm familiar with.

    Using the old strontium in the otolith trick, Investigators in our region have found quite a range in degree of genetic exchange between resident and anadromous forms. Maybe it's because of the differences in the systems. In the Deschutes, most of the anadromous forms spawn in the small side streams, while most of the residents live and spawn in the main river. Is that because the small streams in the basin drastically dry up in the summer, leaving not much for a resident fish? And maybe that's why the degree of genetic separation between anadromous and resident was pretty high in the Deschutes. Genetic separation is lower but significant in the Walla Walla but not detectable in the Touchet. Cedar River steelhead and residents were also found to be closely related.
     
  7. JRSly

    JRSly Oncorhynchus clarki clarki

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    You can order the all the proceedings of the symposium for only $13.00 from the Oregon Chapter for the American Fisheries Society. It includes a lot of really good papers about SRC. It is titled Sea-Run Cuttrhoat Trout: Biology, Management, and Future Conservation. It has some really good papers from the top SRC researchers, so for $13.00 it is hard to find a better resource on SRC. The link below should take you to the "how to order page". Just print out the pdf order form, fill it out, write a check and there you go.

    http://www.orafs.org/market.htm#proceedings

    Hope this helps,
    Sly
     
  8. kamishak steve

    kamishak steve Active Member

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    Something interesting that I read a while back, although it was originally describing salmon, it hold true for any anadromous fish.

    As we all know, when salmon enter a freshwater body, in their flesh they hold nitrates and phosphates which fertilize the river system after the spawning fish dies and its carcass is left in the water.

    Similar to the nitrates and phosphates, I was told that other marine nutrients are brought into freshwater with the salmon. One of those is the level of salinity. As the salmon carcasses die, they release the saline material into the stream. The conditions of the freshwater body actually become more similar to the ocean as a result of the arrival of the salmon. The transition between fresh and salt water is then made less drastic for the young. As a result, the higher the number of spawning salmon carcasses in the stream, the higher the rate of survival for each individual salmon fry.

    Just an interesting thing to note... Just one more reason why our depressed runs have another force against them in survival...
     
  9. jackchinook

    jackchinook Member

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    Absolutely...I should have emphasized more that these are all generalizations. That's one of most incredible things about salmonids is their huge variation of life history strategy within species. My understanding of src's is that, like bull trout/dolly varden, you're much more likely to encounter them in inshore waters/estuaries than the Japanese are in their high seas gillnets (like steelhead, which aren't much found in inshore waters).

    You're right that it's not the single driving force. Perhaps the generalization was too general. Local characteristics will obviously override this general trend, as I pointed out in the Kenai example. Strike it from the record.

    I don't think you're being argumentative and I certainly don't think you're talking out your anus. But consider this; the browns may have come from a 'non-anadromous' population, but where did those ones come from? At one time or another, they had to have come from an anadromous brown trout. Unless, of course, they were from the cradle of brown trout creation...and that would bring God and religion into the discussion...isn't that prohibited?

    Either way, this is about as good as these discussions get. I've always thought this was the coolest element of fish biology.
     
  10. Preston

    Preston Active Member

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    Hmm, interesting idea but I just can't buy it. Rivers are dynamic systems and one of the things that they do best is to flush themselves, particularly here on the rainy Pacific coast. The useful marine derived nutrients that are brought back to the river by returning salmon are those (notably nitrogen compounds) that can quickly be integrated and used by invertebrates and even plants before they can be flushed back into saltwater.

    In the case of salt, the excretory systems of most living things (be they fish, invertebrates, plants or people) function largely to establish a stable saline level, anything much above and beyond that requirement is eliminated and, in a river system, is quickly diluted and flushed back downstream to the ocean. In the case of salmon, the smolting process, which salmonids undergo when migrating to salt water, is a physiological change which allows a freshwater fish to live in salt water while maintaining a level of salt in its tissues similar to what it did during the freshwater portion of its life cycle. Salmon, returning to the river, are no saltier than they were before they left it.
     
  11. Willie Bodger

    Willie Bodger Still, nothing clever to say...

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    This is really quite fascinating reading, keep it up gentlemen.
     
  12. yuhina

    yuhina Tropical member

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    I take a look of the link provided by Paul Huffman http://ykfp.org/steelheadworkshop/ I found several talks that were very interesting and useful for answer people's question here. I attached 2 slides that I crop from the workshop. For what they said is that many species contain 2 different life forms (resid and andro). Steelhead and rainbow trout gene flows to each other very frequently.

    For animals there are many strategies to adapt to different environments, same as life history strategies (resid and andro). And these kind of reproductive traits are largely influenced by the environments and social condition. Steelhead spawning with risident trout are frequently documented. Although these trouts have less advantage to compete for the large female. They frequently used an alternative "sneaking" strategy to sire partial of the eggs. Same behavior happened in the bluegill, some small males looks just like females. They are "sneakers". When big male spawning with female, they frequently dart in and sire some of the eggs.

    In my opinion, for conservation issue, the fact of the genetic identical in Russian (or Northwest) population. It does not mean that the steelhead is no longer important or unique... They just the fact that life goes. And this oceanic life form (and behavior) could be very important in different genetic mechanisms, such as gene flow between different drainages.

    Mark
     
  13. JRSly

    JRSly Oncorhynchus clarki clarki

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    I was actually going to clear this up when I had more time, but you beat me to it, and you did a great job. Nice work Mark. The bluegill reference was right on, another less known example is male pinks doing this with female Chinook. It is pretty rare, but it has happened, I thought it was pretty interesting, a pink Chinook hybrid.

    Sly
     
  14. James St. Clair

    James St. Clair stclairj

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    Im not trying to push buttons here, just providing information. Steelhead and salmon fry don't hatch until the carcasses of thier parents are long gone, and if there is carcass left, it will contain very little salt. Many people believe that the carcasses are their to feed the fry once they hatch. This is generally not the case. While indirectly their nutrients are found in the aquatic insects that the fry eventually will eat, the majority of their post-emergence food as alevin comes from the yolk sac. Once they "button-up" they then begin to eat the aquatic insects containing thier parents nutrients. Fry from salmon that spawn in the fall, say September, generally wont hatch until March/April of the following year. By this time the carcasses have been washed downstream, frozen and thawed, eaten by the aquatic insects and microorganisms, or scavenged by other animals, i.e., their nutrients are locked up in other sources, some of which the small fry will have access to. In the case of steelhead, the adult fish often tries to make it back downstream to the salt, aka a kelt, and unlike pacific salmon if they do die, it will not be near the redd that they produced. There is much more to say here, but I will keep it as short as possible.

    Furthermore, some fry hatch so far removed from the salt, even if the relative salt concentration was higher near the redd, by the time they moved into the mainstem of the river system, the salt concentration would be as miniscule as it normally is in the systemr. Also, some of the steelhead, in the mid-columbia for example, spawn so far away from the Columbia, by the time they did reach the Columbia the salt is diluted to the extent of barely being present (Mid-Columbia R. is freshwater whether the salmon are in the river spawning or not). So the idea that the relative salt concentration from carcasses will make their transition to the salt easier, seems like it actually might make it harder. To go from fresh to salt water, the fish has to change physiologically, which might be very difficult for the little fry. So if they were in a high salt concenttration near the redd, then moved into fresh, then back into salt would be physiologically devestating during their seward migration. Instead, think of the Columbia, or the brackish waters of the mouths of the westside rivers as acclimation areas, where the fish gradually is introduced into the salt water.

    To respond to the topic of this post, (Steelhead = rainbows), they are considered the same species in most cases. The factors that influence whether or not a fish goes to the salt are still trying to be understood. in some cases its easy, while in others its not. This last season I worked on a study in the mid-columbia where hook and line sampling was used to find residual steelhead (basically a steelhead that should have moved to the salt, but instead has residualized and stayed in the river longer than expected) . Everything under 300mm is considered a steelhead, and everything over is considered a rainbow trout. Every fish that was caught was pit-tagged, and this winter antennae arrays will be put into the rivers that can detect the pit tags. Thus, we can get an idea of how many fish are resident and how many are anadromous. While there is much more detail to the study, that is the basic jist, and I mentioned it just to show that the whole steelhead = rainbow thing is still being studied.

    In the wenatchee basin, WDFW considers all O. mykiss caught in any trap or by hook and line to be steelhead, unless they are over 300 mm in which case they are rainbow trout. They all have the opportunity to go to the salt, but some choose to stay, not many, but some. Smolt traps form tiny little streams near Stevens Pass down to the mouth of the Wenatchee show that the majority do move downstream, but not all. We do know that the migration to the salt is ultimatley in response to environmental factors, for example water temps, lack of food, habitat, etc., but have been unable to pinpoint the factor in the case of a specific river or fish. Even head biologists I have spoke to and worked with consider thier best explanations merely theory's, that could be proven wrong within the next few years. As I have said before, in this post and others, I have so much to say, but seem to be rambling on. Hope you all enjoy the info. For article references to some of the info I shared feel free to pm me.


    Gas to get to campus on a saturday: $5
    Lunch near campus: $7
    Not fishing on a saturday to work on my thesis: 100,000 brain cells worth of frustration. (Priceless, in a bad way :( :( :( :beathead:)

    James
     
  15. JRSly

    JRSly Oncorhynchus clarki clarki

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    I can relate. What are you doing your thesis on?