Discussion in 'Steelhead' started by Luke77, Feb 1, 2011.
How about this?
I apologize if this has been mentioned earlier, but I didn't actually have time to read all of the posts here.
If anyone spends any time fishing the Deschutes River down here in OR during the spring, no doubt they will have noticed that many of the redds are highly visible. just about all of the time there is a mix of redbands and steelhead. It's not really a shock to see a single steelhead on a redd with several redband trout and vice versa (Every year I witness this). So it stands to reason that they do indeed interbreed.
now, if we can just get the damn guides to stop sending clients over to dredge the water right on top of the redds so they can get into fish (I'm tired of getting cursed out every time I point this out to them)....but that's for another post.
The reason I said more than 50% is because the effect of hatchery genes has "Cumulative Fitness Decline Effect" see this link for abstract one generation will have ~ 40% decline (if the parents are hatchery fish). However, if two generations were involved in the hatchery program (grandparents and parents are hatchery fish), the fitness will be remain 37% compare to wild fish. That would be -63% decline. That is the reason I use 50% fitness loss. FYI
For those who interested in the history aspect of hatchery fish and population decline. There is one book has a nice section written about it. It is "king of fish : The Thousand-Year Run of Salmon"
A great book from a great scientist and writer David Montgomery who wins prestigious MacArthur fellowship see LINK
My original post was referring to this post of yours:
“The genetic influences of hatchery fish on wild steelhead populations are still a concern,” Blouin said. “But the good news from the Hood River is that the hatchery genes are being diluted more than we thought, and thus may not be having as much impact on dragging down the fitness of the wild steelhead.”
Could this mean that everyone may have to re-think there adamant hatred for hatchery programs and hatchery fish and dams ? Wouldn't that be a bitch if every yuppy blog had to drop that mantra ?????????????
By referring to the two studies and their results, I had hoped to illustrate:
1) the trout/steelhead study did not find that hatchery fish were any fitter than previously thought.
2) The previous study done with the same data is one of the most well-known examples of low fitness of hatchery fish and their offspring.
3) None of the studies address dams and their affects on population productivity.
Your original post quoted above seems to imply that the results of the trout/steelhead study should make people reconsider their thoughts about the poor fitness of hatchery fish or the effects of dams. Given the content of the body of research you are referring to, neither of the conclusions are accurate or appropriate. If you have issues with the methods or findings of either paper that you would like to raise, I am all ears.
I saw David speak this fall at the salmon summit in b'ham, bought his book and enjoyed it. Erveryone should read this book!
Interestingly enough some king salmon populations do have a buffer of sorts, in what is known as "sneak spawning" apparently some smolt don't smolt and become mature entirely in freshwater, then try to sneak into spawning with adult females
There are problems with the Hood River study, Araki et al. 2007 paper in Science, where everyone gets the 60% figure they like to bring up. 1)If you go through the paper's data in the appendix, as I have, you find that the relationship is not strongly significant, only p=.1 for 1 tailed test. Doesn't hold up at all for two tailed. Could have been a stronger correlation if they had another point, but they don't. 2) The impression of a fit to the decrease in fitness per generation curve is increased by selection of data from other studies, while ignoring data from other studies that don't fit the line. But apparently a pretty graph like theirs that fits a popular perception gets you published in Science. See Berejikian's slides at http://www.ykfp.org/par09/ppt/sessiona/day2/html/Berejikian/siframes.html, particularly slides 6, 7, and 8. 3.) The dam on Hood River is out now, so there aren't going to be any more points.
First of all 60% was from one study in one river at one point in time...the number is likely to vary from river to river and time to time depending on the specific circumstances and chance. Regardless of the magnitude of decline, the paper reinforces what other studies such as the ones they have incorporated, show, which is lower fitness of hatchery fish reproducing in the wild relative to wild fish.
Second of all, the Araki paper and others passed peer review...Barry's powerpoint did not. Barry's powerpoint is very deceptive because many of the hatchery programs that he shows having similar fitness over many generations are integrated programs where during those generations a large % of the fish spawning in the wild were of hatchery origin, thus likely dragging down the fitness of the wild population...the very design of integrated hatchery programs is to maintain similarity of wild and hatchery fish...this maintains the fitness of hatchery fish in the wild because new wild genetic material is constantly being incorporated into the hatchery genepool, but, as a result of hatchery fish constantly spawning in the wild, and in many cases outnumbering wild spawners, the fitness of the wild population decreases, resulting in similar fitness of hatchery and wild fish over time, but utimately, lower fitness than what the fitness of wild population would have been if it had been left alone.
Looking at slide 8 in Barry's talk, he notes, "Ford et al found no difference in lifetime reproductive success of hatchery and natural origin coho salmon after about 13 generations of hatchery operation in Minter Creek. However, the naturally spawning population was clearly dominated by returning hatchery produced fish, so the comparison made in this study may reflect as little as one generation hatchery effects."
I would also point out that although there is alot of noise in the data, the mean value for fitness even for supplementation programs is significantly lower than for wild populations.
I really want to believe you, but I would also like to have a formal rebuttal paper to read. You know you can publish this re-analysised data or simply point out the experimental flaws back to Science or Nature! Or better yet, make them retract their published paper from Science! This is how science work right?! We can have all kind of conclusions and opinions, all welcome. But most importantly, what is your evidence? if your evidence strong enough? This research use more sophisticate fitness model and yield multiple evidences about the reproductive fitness. Not just a single relationship you point out here. There are at least 4 papers in this series of study that all point to the same direction... who should I believe? you or this group? I strong encourage you to write up your paper and I am really looking forward to read it.
there are many fish adapt this kind of "sneaker mating behavior" which is another kind of mating strategy. Includes almost all kind of salmonids, and even other warm water fish species... However, this kind of sneaking mating behavior does not automatically constitute another form of genetic reservoir or another "independent" "self-sustain" population. Because precocious females (mature female parr) are rare. and most likely don't have enough viable eggs. So there are only "one" gene pool in the anadromous salmons. No such gene flow thing exist.
Actually, Yahina, the papers that I have read on precocial parr (in Atlantic salmon in eastern Canada before the end of their commercial fisheries) was in males, not females (this phenomenon is also being studied for chinook in the Columbia River system; it appears to occur in both wild and hatchery-released males). Because female reproductive success is so tied to number of eggs produced, being precocial (and producing a pittance of eggs) is not an effective female strategy; it is best to go out to sea where there are abundant food resources and to chance the gauntlet of predators and nets on the slim chance of returning to the spawning grounds as a very large, very ripe mature female. In the case of precocial males, over half the body mass of these little guys were testes; sperm are cheap. As the likelihood of returning via the anadromous pathway dropped, the percentage of precocial male parr increased (see Introduction to http://jhered.oxfordjournals.org/content/92/2/146.full) for example.
You are absolutely right!
mature male parr is rare, mature female parr is even "rarier". The paper I have read is in Atlantic salmon in France 1985. they found about 17 % male parr could potentially produce sperms... and only 6% females parr have eggs, but most of them are not viable...
Sorry for the confusion. I just want to stress the point that even the female could have mature parr form. It is rare in the rare...
Thanks for the good description. I agree with you Steve.
Right Steve - those precocious males in spring chinook are like the pool boys of the population. No need to maintain a spawning territory if you're cute and sneaky.
TomB, yahina - Here it is, a peer reviewed paper pointing out Araki's statistical weakness that I was talking about: http://www.nrcresearchpress.com/doi/abs/10.1139/f2011-087
I find this all very interesting in view of what has changed on the stilly over the years. Back when spotting a school of fifeteen to thirty or more summeruns in a drift was not unusual, like the seventies. The resident trout fishing was pretty good. I even had a partner who would go with me two three times a week and almost always just trout fished. In years past I was always greeted with the response that these were just smolts but of course the difference between smolts and native fish is quite obvious. He would often have good days on 8-12" fish from June on into October. There was even back then a pretty decent green drake hatch that would even get me to trout fish. The river here in front of these my house used to have a good population of trout and also smolts and small salmon at times. We had good hatches with the caddis larva thick as fleas. Now for many years that has been gone , the steel heading went bad about the same time the trout went away along with the insect life. All we see anymore is dogs, silvers and humpies and not too many of those. These changes would seem to reinforce this study. Of course that a river with a food supply that is gone has problems I guess is not rocket science or even marine biology.
yet they use those same studies from hood river to get the state to discontinue the Snyder creek hatchery and move it to the Bogie or Calawah which is a fucking stupid idea.
Okay I understand you guys love your studies but I have to ask. If the hatchery fish are so weak and disrupt the natives how do explain the Clearwater or Grand Ronde who have strong runs of both natives and hatchery fish? Why is it that the dams haven't decimated these runs? I don't understand.
Talked to a side drifting guide couple of days ago who with two clients caught 11 and 8 were natives at Heller bar in a 6 hour trip last week . He said the day before was slow 8 fish but they were all natives. When was the last time you heard of that on the Skykomish or Skagit? What happened?