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New study on steelhead genes - "...up to 40% come from wild trout..."

5K views 73 replies 28 participants last post by  Jim Wallace 
#1 ·
Very interesting article:
http://oregonstate.edu/ua/ncs/archi...w-trout-critical-health-steelhead-populations

1-31-11

CORVALLIS, Ore. - Genetic research is showing that healthy steelhead runs in Pacific Northwest streams can depend heavily on the productivity of their stay-at-home counterparts, rainbow trout.

Steelhead and rainbow trout look different, grow differently, and one heads off to sea while the other never leaves home. But the life histories and reproductive health of wild trout and steelhead are tightly linked and interdependent, more so than has been appreciated, a new Oregon State University study concludes.

The research could raise new challenges for fishery managers to pay equally close attention to the health, stability and habitat of wild rainbow trout, the researchers say, because healthy steelhead populations may require healthy trout populations.

In a field study in Hood River, Ore., researchers used DNA analysis to determine that up to 40 percent of the genes in returning steelhead came from wild rainbow trout, rather than other steelhead. And only 1 percent of the genes came from "residualized" hatchery fish - fish that had stayed in the stream and mated, but not gone to sea as intended by the hatchery program.

"It used to be thought that coastal rainbow trout and steelhead were actually two different fish species, but we've known for some time that isn't true," said Mark Christie, an OSU postdoctoral research associate and expert in fish genetic analysis. "What's remarkable about these findings is not just that these are the same fish species, but the extent to which they interbreed, and how important wild trout are to the health of steelhead populations."

This research, just published in the journal Molecular Ecology, was based on a 15-year analysis of 12,725 steelhead from Oregon's Hood River, each of which was sampled to determine its genetic background and parentage. It was supported by funding from the Bonneville Power Administration.

The study reveals a complex picture of wild trout and steelhead intermingling as they reproduce. A steelhead might be produced by the spawning of two steelhead, two wild trout, or a returning steelhead and a trout.

Rainbow trout are small to moderate-sized fish in most rivers, but if that same fish migrates to the ocean it can return as a huge steelhead weighing 30 pounds or more, prized for sport fishing. Researchers still don't know exactly why some trout choose to go to the ocean and others don't, although they believe at least some part of the equation is genetic.

Studies of rainbow trout and steelhead have been undertaken, in part, to better understand the implications of hatcheries. Including all salmonid species, more than one billion hatchery salmon are released into Pacific Northwest streams each year. And because hatcheries produce fish that are less able to survive and successfully reproduce in the wild, there is concern about hatchery fish mating with wild fish.

"One implication of this study is that the genetic contribution by wild trout is diluting the input of genes from hatchery fish to the wild steelhead population," said Michael Blouin, an OSU professor of zoology and co-author on this study.

"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."

The genetic influence of wild rainbow trout, the scientists said, is roughly cutting in half the genetic input of hatchery fish that reproduce in the wild - a mitigation of their impact that's of some importance.

The scientists cautioned that results from one river might not be representative of all steelhead populations. Nevertheless, Christie said, "The importance of trout in maintaining steelhead runs should not be underestimated.

"They can act as a healthy genetic reservoir and preserve reproductive populations during years when ocean conditions make steelhead survival very difficult," he said. "So a good way of looking at it is, whatever is good for wild rainbow trout is also good for steelhead."

Worth noting, the researchers said, is that most other salmonids, such as coho or chinook salmon, do not have this type of fall-back system to help produce fish with a higher capability of surviving. As such, they may be more vulnerable than steelhead to the concerns about genetic weaknesses produced by hatchery fish.
 
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#2 ·
This is exactly why all steelhead rivers should be Cand R only for ALL TROUT! I think that the 1% dilution of hatchery genetics is very interesting, And I would love...LOVE to see more studies on this race of fish, as well as others to further assess the validity of the study. I have suspected for a long time that the difference in spawning times between hatchery winter fish and native runs would minimize actual interbreeding of the two strains.
Im not saying the hatchery fish don't spawn, I just think they most likely spawn with other hatchery fish in the system for the most part.
I would also be interested to know if, when the steelhead and resident trout breed, if it is the case of male steelhead and female trout, or vice versa, or if there is even a propensity towards one or the other
 
#7 ·
The dilution may also be misreprsented because when wild winters spawn with hatchery winters none of the offspring survive to adulthood. You would not see dillution at all unless you studied parr. Even then it stands to reason that given their lack of genetic fitness these crosses would be sampled less frequently.

WDFW is betting that you are correct with respect to spawn timing. This is only one issue though. It seems downright arrogent to me to think that we can engineer hatchery fish in such a manner that they do not effect wild fish. Further, the real issue with our PS populations is in the sound itself. I have never been given any possible realistic scenario where hatchery fish are aiding in wild fish survival in the PS. I can think of many possible scenario's whereby they have severe negative affects.

Go Red Sox,
cds
 
#3 ·
I've always been confused by the distinction between resident and anadromous versions of the same fish. After all, some rainbows live in the same watershed as steelhead but don't go to sea.

In this study, Mark Christie says that resident fish act as a genetic reservoir in case of a poor ocean return. That is the best reason that I've heard.
 
#12 ·
I've always been confused by the distinction between resident and anadromous versions of the same fish. After all, some rainbows live in the same watershed as steelhead but don't go to sea.

In this study, Mark Christie says that resident fish act as a genetic reservoir in case of a poor ocean return. That is the best reason that I've heard.
There's a good article about this in an issue of flyfishing & tying journal by John McMillian. I don't have it in front of me, but from what I can recall, steelhead will residualize if conditions are right. Temperature, food and stable flows are somre of the factors. It seems to be more prominent in males, as size is an evolutionary advatage in females. Their offspring may or may not go to sea, dependant on conditions. In that article there's a picture of a pair of steelhead ready to spawn with a "satelite" resident male right behind them ready to sneak in and fertalize.
 
#4 ·
Have you ever watched the fish spawning. The little stay at home fish also get in on the action. A small male will actually throw out some sperm on the laid eggs.. So who's to say only the wild fish spawn. A hatchery fish came from a wild fish so spawning is in their genes. All this is beyond me so I don't try to figure any of it out.
 
#5 ·
See thats what Im thinking old man. Do residents truly breed with steelhead, or is it resident trout males releasing their milt alongside a steelhead pair? Inquiring minds want to know. There are so many intriguing evolutionary adaptations for breeding in salmonids. I was very interested when I learned that some jack salmon imitate the coloring of females to allow them to slip in during paired breeding to release their milt.
 
#6 ·
I was very interested when I learned that some jack salmon imitate the coloring of females to allow them to slip in during paired breeding to release their milt.
Interesting!
 
#9 ·
An excellent summary of what has been know (though often ignored) for some time.

The key sentence in regards to your question in what the life histories parents of those returning adult steelhead is -

"A steelhead might be produced by the spawning of two steelhead, two wild trout, or a returning steelhead and a trout."

It has been clear for some time that O. mykiss is a single species that in complex river systems like this region's anadromous waters have complex life histories that are often interwined. Those same complex life history interactions are also seen in our coastal cuttrhoat and bull trout.

Those mature resident fish are at least as old as their larger anadromous cousins and often there are more repeat spawners in the resident population than the anadormous population. Regardless those resident fish represent a significant diversity of the species and should be consider important from both a genetic diversity and population stability view.

The resident fish while similar in size to "Jacks" represent more than just age diversity.

Stilly stalker -
When an anadromous adult and resident adult interact during spawning by far the most common pairing is a larger anadromous female with a smaller resident male. And yes in those cases the resident male is actively spawning with the female. It is probably important to emphasis that when a female steelhead (or other salmonid) spawns those do so in a series of events. Rather than depositing her eggs all at one time the spawning with be divided into a number separate egg deopistion events. With steelhead the female will deposit her eggs in a dozen or so separate pockets with each separate deposit cover by gravel. The overall spawning process typically takes 1 to 3 days during which the female may construct more than one redd (which can be separated by significant distances).

Anyway because each of the female's egg depositions are often separated by 1/2 hour to several hours it is not uncommon for a number of different males to fertilize portions of her eggs. While we tend to think of the spawning as a pair of fish it is often the case than more than one male maybe in the area of an active spawing female. When there is more than one male they typically engage in behavior ("fighting") to determine dominance or "spawning rights". That fighting typically includes chasing, butting, and even biting. The dominate male typcially slides along side of the female at the time she releases a portion of her eggs releasing his milt at the sametime. While that is the norm it is not uncommon for a second male to slip up on the opposite side and also contribute to the spawning.

Have seen a resident male spawn with the large anadromous female under several scenarios. The first is when there are not anadromous males in the area; though there can be multiple resident males. The second is they can be that "sneaker" male that slips up on the opposite side of the female from the dominate male. And finally it sometimes the larger andromous males are so busy with their own battles for dominance they leave the "field' open for the opportunistic resident male.

I'm in agreement with the importance of CnR of those resident rainbows for the over all health of our steelhead populations it is equally important that any CnR regulations include at least a bait ban (selective gear rules would be even better) whenever fishing occurs. The hooking mortality associated with CnR of bait caught trout quickly negates much of the value of CnR. The resident adults are subject to that hooking mortality whenever they are caught in the summer or winter.

Tight lines
Curt
 
#10 ·
So Curt, what about the situation of adult anadromous male spawning with a resident adult female? Not happening or just rare? In addition to this, are the chances better of the offspring being anadromous if both parents are as well?
 
#13 ·
This is one of the best threads I've read here. Thanks for all your insights. I'm hoping to walk the shores of the Raging, Snoq and Tokul in the known spawning areas over the next couple months so I can watch them breed. Luckily, these are all very close to my house.

Cheers,
Mike
 
#15 ·
Luke -
Whether with bull trout or O. mykiss I have not seen those larger anadromous males spawning with small resident females. While I don't know if anyone knows for sure why that is the case it seems to me that two factors may play a role. One is that those small females often construct their redds in locations (shallow water) that would make it difficult for those large males to be functional spawners. The other of course is that those large males may intimidate the smaller females. Of course both of those would be less of an issue with older/larger females. I have seen resident females well in excess of 20 inches.

mbcracken -
You should start seeing some wild steelhead spawning in early March continuing on into June on those streams. The peak spawning activity will be the later part of April.

Tight lnes
Curt
 
#16 ·
Curt's concern about the impact of bait fishing on preserving resident rainbows is likely to prove to be a sticking point for some. After all, salmon and steelhead eggs are a central part of the arsenal of many gear fishers, especially when fishing for hatchery salmon and steelhead. Expect to hear loud cries if a wide-spread ban on bait fishing is proposed; imagine if bait were outlawed on the Cowlitz.... [Actually, I can; I think that it would become a fabulous trout river - lots of bugs and productivity.]

Steve
 
#19 ·
“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 ?????????????
 
#20 ·
"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 ? Wouldn't that be a bitch if every yuppy blog had to drop that mantra ?????????????
That's one study from one river, most of the evidence points to hatchery fish having a negative impact on wild fish, there are other impacts aside from loss of fitness. I'm not saying that hatcheries don't have a place, but as they are run now they are not the answer.
 
#22 ·
Excellent article and follow-ups ladies and gents..

Now if we could just get our policymakers to make positive change with these issues instead of the "we need more research data" repeat. :beathead:
 
#23 ·
I just glimpse through the original paper. below is my quick thoughts.

1) Hatchery fish is BAD.
This study was carried out in the Hood River, Oregon. Same research group found the hatchery fish decrease the wild run's fitness (life reproductive success) by more than 50% (Science paper, 2007?). Same river, same population. so what is the message? Gene exchange with hatchery fish is low (it depends on the hatchery program in the future), BUT gene exchange with hatchery fish still will cause the damage of 50% fitness loss on those hatchery offspring and also other unseen competition issues with the wild offspring.

2) 40% gene exchange (gene flow) with wild rainbow trout is the natural phenomenon of evolutionary consequence and processing. This is nothing new to biologists as Curt mentioned it earlier. The neat thing about this study is that they are the first time to quantify how many fish are doing it. Because of the location in the Hood river,they can capture every returning fish (below the dam) and do the grandparents pedigree analysis, that mean they can pin point their parents ID, grandparents ID by using the genetic markers (every individual has different genetic profile - just like fingerprints), and also this technique allow them to assign the unknown resources to the rainbow population (which they don't need to capture those fish).

3) 40% gene exchange with another residential trout could provide another buffer mechanism for steelhead, compare to other salmonoids (king salmon), those other species don't have this kind of luxury "buffering mechanism". This is the authors want to indicate, if everything being equal, Chinook and Coho will have more trouble than Steelhead, because they don't have residential population like those rainbows. So if some thing bad happen in their genetic property, steelhead "should" have better resistance because of those wild rainbows genes. What is a message? We got to take care of those rainbows too, they are a whole package deal.

4) For the genetic integrity point of view, I am not that worry about angling pressure on the residential trout. Instead, I will be more concern about how the hatchery program practice, and if there are any stocking rainbow/ cutthorat trout issues in this river.

Mark
 
#35 ·
Read the first line in YOUR post, that's where i got it , I checked all your links, none of which supports YOUR original statement.... Misinformed, Are you misinforming us?
Biased you say? Might you be biased?? My question was not about Dams to you , re-read above if you need to re -focus on the topic.
Maybe you should read a little before you cut copy and paste the gospel .... I asked you to back up your statement with a link to support the statement you made:
"This study was carried out in the Hood River, Oregon. Same research group found the hatchery fish decrease the wild run's fitness (life reproductive success) by more than 50% " You bailed on the topic, accused ME OF BEING BIASED AND UN INFORMED . Looks like factual clarity is something you are not privy to on this one ... Others ??
That's all we needed to know-
 
#24 ·
Richard -
]I agree that it would great to see more management changes/regulations responding to the importance of the resident trout.

However it may well be the largest obstacle to those changes continue to the apathy of the users - us. Over the last several decades there have several attempts to put in place regulations to accomplish more holistic management and in every case those attempts have been met with either yawns or opposition from the anglers of this State. While a few anglers are willing to lobby for spedific changes those efforts are typically limited to only those changes that directly effect their passionate interests - CnR of wild steelhead is about the only example.

I see no evidence that apathy is going to change. The only changes we are likely to see will probably be piece meal and will come from the efforts of a very small handful of individuals or the State (without much encouragement from the users).

Tight lines
Curt
 
#26 ·
Dramatic drops in the reproduction rates of released hatchery fish were previously reported in a 2007 issue of the journal Science. The study noted the effects could be explained by a natural selection that favors characteristics useful in a sheltered, predator-free artificial environment over those necessary in the more hostile natural world. Of the large numbers of eggs laid by the released mothers during spawning, only a small fraction ever reached adulthood-the few that were best suited for survival in wild conditions.

An article talk about those series of research: LINK

http://www.scientificamerican.com/article.cfm?id=fish-hatchery-silverhead-salmon-genetics

Araki and his colleagues looked at the Hood River steelhead supplementation program in Oregon and found that trout fry raised by two hatchery-reared parents had just 37 percent of the reproductive success of those with two wild-born parents, even though both sets of offspring were born in wild waters.

Science abstract: http://www.sciencemag.org/content/318/5847/100.abstract
 
#33 ·
Nothing above supports this:

"This study was carried out in the Hood River, Oregon. Same research group found the hatchery fish decrease the wild run's fitness (life reproductive success) by more than 50%"

are you sure this is accurate Yuhina? Did I miss something ?
 
#30 ·
" The contribution of genetic material by wild resident fish to wild steelhead populations MAY dilute the negative effects of anadromous hatchery fish spawing in the wild"

"MAY" being the definative word in that sentence.
 
#32 ·
Very interesting article:
http://oregonstate.edu/ua/ncs/archi...w-trout-critical-health-steelhead-populations

1-31-11

And only 1 percent of the genes came from "residualized" hatchery fish - fish that had stayed in the stream and mated, but not gone to sea as intended by the hatchery program.
Just to be clear,

the 1% of "residualized" hatchery fish is the fish stay in the stream (river dwelling fish from hatchery program). This 1% did not includ other hatchery fish that went to the ocean ( hatchery steelhead).

If you included all hatchery genes that flow into anadromous Hood River steelhead, that would be 19% (18% hatchery anadromous + 1% hachery resident).
 
#36 ·
For those who interested ...

a paragraph from the original paper - Abstract " ...additionally, we documented that resident hatchery males produced more offspring with wild anadromous females than with hatchery anadromous females. One explanation is the high fitness cost associated with matings between two hatchery fish..."
 
#38 ·
Nope, doesn't answer the simple question i asked, tom didn't even see that my info was a Paste from YOUR POST !!!
Priceless!
You read toms post again if you like , I'm gonna go look for facts, not agenda driven opinions-:thumb:
 
#43 ·
Charles,

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
 
#40 ·
The WSC has been submittting regulation calling for increased protection of resident rainbow trout, provided is the our testimony to the Commission in '09. We urge others to do the same.


Good afternoon, The Wild Steelhead Coalition would like to thank the commission and WDFW the opportunity to provide testimony. We would also like to commend the department for putting forth some good proposals that will benefit wild steelhead.

However we would like you to pay particular attention to the WSC comment regarding proposal #23 and take this opportunity to bring focus to the importance to protect wild riverine rainbow trout, the resident form of wild steelhead and the importance to protect this vital element.

The WSC has provided each Commission member a copy of John McMillian’s article published by the American Fisheries Society on resident rainbow trout and wild steelhead interactions.

Research is showing that resident rainbow trout in our anadromous highways and by-ways plays a significant role in the diverse life histories of wild steelhead. Resident rainbow trout, through participation in the late winter/spring spawning interactions of wild steelhead improve the success of fertilization of female steelhead, especially during April, May and June. During this period, male wild steelhead become depleted and the steelhead population is in part reliant on rainbow trout to provide the male partner for spawning.

Steelhead and resident rainbow trout can produce independently the opposite form and resident rainbow trout can be the leading or single source of anadromous smolt production when the abundance of steelhead is depleted or extinct.

The WSC finds it scientifically enigmatic to understand why the WDFW can protect one form of steelhead trout, the anadromous steelhead, but continues to allow harvest and/or gear methods that induce high mortalities of the other form, the resident rainbow trout. Both forms, by definition and taxonomy are classified as the same species, steelhead trout, and are genetically the same in each watershed. Each form contributes to the abundance and productivity of the other form.

Rainbow trout can be an important component in the recovery of wild steelhead stocks and the rebuilding of declining stocks. Improved regulations are needed to protect resident rainbow trout

We encourage the WDFW to pursue stream management strategies that protect all juvenile wild salmonids and rainbow trout while continuing to allow selective fisheries for adult salmon and hatchery steelhead. Aside from being confusing proposal #23 needs to be simplified and provide stronger regulations to further protect resident rainbow trout.

Respectfully Submitted,

Wild Steelhead Coalition
 
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