Met'lheadMatt,

I've responded to posts of yours before, so I know that you hang out on this board at least some. I don't know if you do so consistently enough to have not missed the previous and extensive threads on this very topic of the effects of hatchery fish on wild fish. The science is clear in that there are effects, and they are invariably negative to the wild fish population, where the species is a stream rearing obligate. Writing as you have in starting this thread suggests that either you haven't read the plentiful material available on this topie, or that your reading comprehension suffers. I'll give you this, that there is the remote possibility that you have both read and fully understood the genetics studies and are qualified to conclude an opposing interpretation.

The following is a post I made on another board about this same subject a week ago. It uses hypotheses that are consistent with observations made here in the PNW, but I simplified it for convenience and to be understandable to the layman reader. Perhaps it will help your understanding.


"We don’t all go through this debate. Some of us seek the truth and go where it leads us. I don’t think there’s much to debate about hatchery and wild fish genetic fitness unless you’re seeking something other than the truth. But there is a lot to discuss.

The Hood River studies are among the most recent steelhead genetic studies. Some earlier work was done on the Kalama River. Google is your friend. There was some work in California also, but I’m not sure if I have a copy of that study. And a Cowlitz steelhead genetics study was finished a year or so ago. I know I can find that easily and send you a copy if you like.

You can look up who funded the Hood River studies, but the tone that you write with makes you appear biased. A biased person is less likely to be open to objective information. So would it be a waste of time discussing salmonid genetics with you?

As far as I know there are no studies showing that wild fish have higher or lower smolt to adult return rates (SAR) than broodstock hatchery fish (which is a generalized term in itself and needs more concise definition to be useful in discussion). Lack of research is a serious problem with many of our fish programs, both hatchery and wild. But making up conclusions about what is going on in the absence of real data is never a sign of intelligent thinking.

You asked, “If hatchery fish are so terribly unfit and the spawning of them with wild fish produces nearly zero new fish, how have our fish runs survived since the first hatcheries were started as early as the 1900's?” The short answer is that we have continued hatchery programs for over 100 years. If you’re actually serious about this and are open to seeking the truth and going wherever it leads you, there is more to it of course.

Are hatchery fish “unfit?” What is fitness? Maybe you’re familiar with the term “survival of the fittest?” It’s an hypothesis, never proven false, that in the natural environment, the fittest animals survive to reproduce their kind and perpetuate the species' survival over time. Animals that are weak or diseased typically are taken by predators and removed from the breeding population. Some healthy animals are removed from the breeding population by chance – they happened to be in the wrong place at the wrong time, and zap! – eaten by a predator. But overall the animals that survive and reproduce are the fittest, and they pass those attributes of fitness on to the next generation.

So what about that hatchery fish? Well, hatchery fish begin with native wild broodstock, the kind that are of the highest fitness in the natural environment. We science dweebs, regardless of who we are bought and paid by, would say this fish has a reproductive fitness in the natural environment of 1.0, as in 100%, it doesn’t get any better than this. OK? Now we spawn these native wild fish artificially and rear their offspring in a hatchery environment, not the natural environment. (If you don’t believe in evolution and Darwin’s theory, you may as well stop reading right now and go live in ignorance.) Rearing the juvenile fish in a hatchery environment unavoidably selects for traits that are conducive to survival in the hatchery environment, not the natural environment. Why? Because the two environments are significantly different. In the natural stream environment a juvenile fish must continually make a choice, a compromise if you will, between foraging and hiding from predators. It must forage to survive and grow. And it must avoid predation in order to survive. It’s not easy to have it both ways. But only those who successfully do both will survive to reproduce.

Predators are kept out of the hatchery for the most part. The eggs are incubated in clean water, free of silt, so egg-to-fry survival is high (although this isn’t genetic selection). Food is provided by hatchery staff, so the fish don’t have to learn how to forage like their wild counterparts. The fish that survive hatchery life, which is most of them, have heritable traits. They will pass on those traits to the next generation if they survive to spawn. Those traits are genetic attributes. And those traits are the traits of easy living: food comes to them; they don’t have to go foraging to find it. And they never see a predator during their juvenile life.

And then the hatchery fish are released into the natural stream environment at the time they are genetically programmed to migrate to the ocean. Unfortunately they haven’t had good training or life lessons in predator avoidance, so on average, more of them are taken by predators along the way than of their wild brethren. (Always hanging around near the water surface where the hatchery food came from makes them easy targets for the terns in the lower Columbia River (LCR)). Some data show wild SAR as higher than hatchery fish SAR, which stands to reason. But science can be muddy, just like real life, and sometimes we get data showing hatchery SAR just as high as wild fish – especially coho, but then juvenile coho have always seemed to be the street fighters among the salmonid crowd.

About two years later our hatchery fish return to freshwater, and some will escape the fishery and stray and not return to a hatchery rack. This F1 generation of native broodstock hatchery fish will spawn and pass on its heritable traits to the next generation of fish. But what are those traits? Well the obvious and important ones are these: 1. Food just comes to you, and you don’t have to go forage for it; and 2. As a juvenile there are no predators you need to watch out for. As you might now understand, this isn’t gonna’ be a big help in the survival department. OK, so how much of “not a big help” is it?

From our example so far you can probably see that the hatchery effect on fish depends how long they live in a hatchery environment. Juvenile coho and steelhead and spring Chinook live one year in the hatchery, so they have one year of “soft easy living” and not having for forage or avoid predators to their experience. In their ocean life they had to forage and avoid predation just like wild fish. And if we were to use pink or chum salmon in our example, you would see that the hatchery effect only provides higher egg to fry survival, with the young fish being released with little or no artificial feeding, and therefore very little of that “soft easy living” in a hatchery. Because our hatchery fish here are from native wild broodstock, they are an F1 generation, one generation removed from the natural environment as juvenile fish. For easy arithmetic, we’re going to assign a natural reproductive value of 0.85 to these fish. Although they are a lot like their native wild counterparts, they’ve had some bad training when it comes to surviving as juveniles outside a hatchery in the natural world. The actual value could be higher, or lower, but this should serve to illustrate what happens, and it is consistent with limited real observations. In fact, the limited studies would support assigning an even lower value to F1 returns. If you were one of those students who avoided science and math, this part may get difficult, but this is written for those who can at least balance their own checkbooks.

When two native wild fish spawn in the natural environment, it goes like this:

(1.0 x 1.0 = 1.0) This means the offspring have the same genetic fitness as their parent generation, and they are as well equipped to survive as is possible. They will know how to forage and avoid predators as well as can be expected.

When two native broodstock hatchery fish spawn in the natural environment, it goes like this:

(0.85 x 0.85 = 0.7225) This means that the offspring, although like their parents in most ways, don’t have the same innate foraging and predator avoidance skills (and probably some others, but we're keeping it simple here). So they have a survival potential of not quite ¾ of what the native wild fish have. They will produce fewer smolts, and those smolts will survive and reproduce at a lower rate.

When a native broodstock hatchery fish spawns in the natural environment with a native wild fish, it goes like this:

(0.85 x 1.0 = 0.85) This means that the offspring will be more fit than a HxH cross, but less fit than a WxW mating. So any time a hatchery fish spawns with a wild fish, the potential productivity of that mating is less than a mating of two wild fish. This means that hatchery fish, even native broodstock hatchery fish, cannot benefit a wild population, EXCEPT under one condition I’ll get to in a minute.

While we’re doing some arithmetic, we should consider that most hatchery programs do not use native wild broodstock sources. They use long-term hatchery broodstocks. A key example of this is the Chambers Creek winter run hatchery steelhead in Washington. These broodstock came from a couple local wild populations in the 1940s, so they have been cultured and selected for favorable hatchery traits for over 60 years. Why do I bring this into the discussion? Because our native broodstock hatchery fish are F1 hatchery genetic material. This is important because they have potential productivity of 0.85, which is not that much less than 1.0. Our Chambers Creek hatchery broodstock are something like F20. Although it doesn’t work exactly like this, we’ll use simple math and say they have potential productivity of 0.038, or about 4% of what a wild fish has.

This explains why, after 60 years of releasing hundreds of thousands of Chambers Creek hatchery smolts each year from many dozens of rivers, the rivers are not crammed full of wild steelhead that resulted from these hatchery fish spawning in the natural environment. I think this 20 generation value of 4% is incorrect, and an exaggeration on the low side, but I cannot prove it. However, it does generally support why this particular hatchery stock performs so poorly when it spawns in the natural environment.

Are all hatchery broodstocks this bad when it comes to natural spawning? I don’t think so, but again, I don’t have data to prove one way or the other. However, our Skamania summer run broodstock, for another example, spawns closer to the same time as native wild summer runs do, unlike the Chambers fish that spawn months earlier. A general hypothesis is that the more the hatchery fish are like the wild fish they came from, the higher their reproductive success will be. See the F1 compared to F20 above. So pink and chum hatchery fish appear to be less affected by hatchery treatment than steelhead.

About that EXCEPTION I mentioned. Hatchery fish can help a wild population when the wild population is severely depressed and on the brink of extinction. An example would be the mid-Columbia River tributaries where the steelhead are ESA listed. All wild steelhead that escape and a large number of hatchery fish are allowed to spawn naturally. While those hatchery fish have low reproductive potential, they have some. A small number of juveniles may survive to smolt. By definition, those that do are more fit than the ones that don’t. Above I gave F1 native broodstock hatchery fish a potential productivity of 0.85. If fish can lose 15% of their potential in one generation, they can recover about the same amount in one generation. So with each passing generation, the few hatchery fish that do successfully reproduce increase their potential productivity by 15%. In theory, and this is still unproven theory, as populations of wild fish that are supplemented with hatchery fish, the population’s potential productivity will approach 1.0 and not be measurably different than original native wild steelhead, provided they are not continuously diluted with more hatchery fish matings. Well, that’s the plan, but it will be years before we know if the theory is correct.

But this does get at your last point about introductions around the world. Steelhead, brown trout, and salmon are thriving in waters far from their native range. They are from hatchery stocks. I can only surmise that they retained some potential productivity for natural environments and that with each passing generation it is increasing toward 1.0. These examples don’t prove, but they do support the hypothesis above that genetic fitness can increase and well as decrease by passing positive heritable traits from one generation to the next."

Your post above at 7:28 AM is indicative that you know less than you think you do. You wrote: ". . . they hatch, they grow, and they return. without us feeding them, just giving them a place to play. . . ." It appears you subjected hatchery origin fish to the selection of the natural environment, which is fine. What % returned? That is key, because to the extent that this type of action has been monitored, the adult return rate has been statistically no different from zero. That doesn't mean no fish ever survive to return, only that the number is so low that zero is within the error bounds of analysis. Then you wrote: ". . . help with egg boxes, which work. . . ." Technically you're correct, providing you're referring to pink, chum, or sockeye salmon. However, you're absolutely wrong with respect to monitored efforts done with chinook, coho, and steelhead. So you'll need to name the species, stock, time, place, and biologist in charge to buy some credibility about these eggs boxes that worked. Then you said, ". . . you can read anything you want into any written document, . . ." This too, is true. However people well informed on the subject, reading the same documents, tend to reach the same conclusions. The obvious exceptions of course, would be the scientists employed by tobacco companies who managed to conclude that smoking doesn't cause cancer. Your writings in this thread tend to place you in that catagory.

Sincerely,

Sg