Just one generation in a salmon hatchery ruin salmon for thriving in the wild

Most people know the inspiring story of the salmon. Hatched in the gravel of a rushing mountain stream, the smolts are pulled by the waters downstream past logjams, lethal crevices in the rock, and sometimes into side pools from which there is no escape.

Mile-after-mile, sometimes many hundreds of miles, the river grows but nowadays too often the smolts die in the slack waters of a reservoir, plucked out by predatory birds or fish or simply by their own biorhythms, now turned against them.  They begin to turn into a salt water fish hundreds of miles from the sea because of the lack of a current to pull them promptly to the ocean.

Those few that still make it to the sea grow big but have to dodge their natural predators, such as orca, and sea lions, and artificial dangers such as pollution and parasites from penned salmon “farms”.  Over the years the numbers of wild salmon have dwindled. Managers (and don’t all wildlife today have to be managed?) have decided to build hatcheries, trying to flood the streams with so many smolts that it doesn’t matter if only 0.1 % fight back upstream to return to spawn.  Those that do now are usually spawned in an artificial place by humans. The new hatchery smolts live an easy life at first, but scientists have now found that this human easychair likely ruins a run’s fighting spirit, their natural ability to survive, in just one generation.  In fact, those most adept at hanging around the hatchery do slightly better  surviving outside than the natural born fighters.

Story: Hatcheries Change Salmon Genetics After a Single Generation. ScienceDaily






  1. jdubya Avatar

    Basically what they measured was reproductive success in the hatchery versus the ability to spawn in the wild. They captured two sets of brood stock, one set of completely wild Hood River steelhead, and a second set that had been wild prior but had gone through one round of hatchery rearing. Both sets were reared in the hatchery and the offspring released as juveniles (called the F1 fish). These fish came back and were allowed to spawn in the wild. Their offspring (called the F2 fish) spent their entire lives as wild fish and were counted when they came back to spawn as adults (this survey began in 1992). So the main question is which of the F1 parents were more successful at creating F2 fish in the wild?

    So who did better? The brood stock in the hatchery that were the most efficient at creating lots of F1 stock turned out to have the lowest level of success creating F2 fish in the wild while the brood stock that were the least efficient at creating the hatchery F1 fish had the greatest number of F2 fish return. So a straight trade off between performance in the hatchery versus performance in the wild. And this wasn’t following just a few fish..the yearly mean of smolts released was 52,700 fish.

    Why did this happen? It wasn’t due to loss of fitness due to inbreeding and it wasn’t due to any specific mutations, but instead somehow these fish, simply had a domestication selection that leads to the selection of fish that perform well in the hatchery. And what is most amazing about this study is that this selection occurred after only one generation in the hatchery.

    Which this means is that fish bred in the hatchery, released to mature and then come back to the hatchery for another round of breeding and release, over and over again, these fish will have dramatically lower fitness levels for breeding in the wild than the wild fish. So when you exterminate the wild fish and live solely upon hatchery fish, that fishery is screwed.

    1. SEAK Mossback Avatar
      SEAK Mossback

      One of the things hatchery operators always say is “How could we be having any selective effect? Nearly 100% of our fish survive from fry to smolt in the hatchery.” The difficult point to get across is that the actual mortality associated with selection in the hatchery occurs after release when fish that did well in the hatchery also do better in the ocean, as traits selected for survival in the ocean phase are quite different than in freshwater where territoriality is an important factor.

      Most of this work has been done with steelhead — I would like to see more with coho, a highly territorial species in most freshwater habitat that is reared in high density in a hatchery environment requiring nearly the exact opposite traits for success compared with those required in the wild.
      This is one reason why I think depending entirely on lower Columbia coho, extant now only in hatchery broodstock with 4 decades of intense domestication behind them, to repopulate habitat in the Columbia system is a long shot, and it would be much better to somehow take related fish (based on genetics and glacial movements in the past 10,000 years) from natural stocks in the Thompson system in the upper Fraser. But those stocks are hard pressed, so donor broodstock may be difficult to come by.

      1. jdubya Avatar

        Your point is spot on about the coho.

        What this study does not really answer is how long would it take to regain wild status after one round in the hatchery which is one way wild stock could be amplified for a Fraser to Columbia transfer.

        Of course, with the mess of the viruses in the BC salmon, maybe transplanting right now is not the best thing to do regardless.

  2. Doryfun Avatar

    This study re-affirms the very concerns that our mitigated hatchery system has to long range solution for anadromous fish run problems, that have for so long been suspect by many fisheries biologists I have heard over the years.

    The sad thing is, that businesses like mine, that limp along with economics of hatchery fish, enabling us to fish, come at the expense of dilution of the gene pool and questionable long range answers to survial of our wild fisheries. (and fundamental seed source).

    Most of the excited fishermen who have landed a fish in my boat, don’t seem to care that much, what kind of a fish it is. Many don’t know the difference, and as each successive generation of fishermen get that much farther removed from knowing that “feel” of “wild” difference on the line, they will probably even care less. So I guess fish are not the only thing that feel the effects of evolution in just one generation.

    What I worry about more, is that as people get more attached and consumed by their own machines, and spend less time inter-acting in nature, what will be their level of compassion? It is hard to have compassion for things when you lose the ability to “feel.”

    On a second note, do any of you fisheries people know what kind of success the Nez Perce have been having with their hatchery program (copying nature to the 9th degree – releasing smolts high in the tribs, trying to establish runs (not clipping adipose fins)to simulate nature (wild runs) more than the normal hatchery situation? I believe some of the Idaho hatchiers may have been trying this to some degree the past few years too??

    1. Salle Avatar

      Here’s a rather informative article on the Nez Perce hatchery’s “supplimentation” program:

      Nez Perce hatchery strategy pays big dividends for Snake River fall chinook, raises big questions for Northwest



      I would like to add a bit of the philosophy explained to me by both Nez Perce and Shoshoni hatchery managers and operatives…

      It is said, by the tribes, that the fish have a memory of where they came from, a memory of the place and the stones in the streams where they were born as well as along the journey to the sea. In placing young fish who got their start in a tribal hatchery into wild streams by a certain early age, this memory will develop and they will return there to spawn when their time comes. And many do. Modern science, this is one of my few criticisms, doesn’t allow for such thinking.

      Seems like it might be working from the articles posted here. There are far more extensive details, more than I could relate here, but the philosophy seems to me, to be sound and doable, if they are allowed to carry on with this sort of “supplementation” with fish that originated in that waterway. NOAA should either let them continue this practice or promote the removal of those damned dams.

      I laud the endeavors of the Nez Perce and Shoshoni have made several statements to that effect in the past, even on local TV. Truly, the upstream fisheries, and other species who rely on these fish, would really be screwed if it weren’t for the preservation techniques the tribes have developed to protect and retain species they have relied on for hundreds to thousands of years… or since time beyond memory, according to federal Indian Law.

      (Personally, I think the lack of salmon return to the northern Rockies is one of the reasons that the forests of the northern Rockies, as elsewhere, are dying from disease and beetle infestations. These forests (the trees in this case but expands to other inhabitants in primary and secondary levels of the food/nutrient chain) have been denied ocean derived nutrients for such a long time that it has caused them to become susceptible to disease, blight and insect infestations like the bark beetles as theorized in peer-reviewed studies as far back as 2000.)

      1. rork Avatar

        Simply slowing the speed at which we loose genetic diversity doesn’t seem like much of a goal. It’s just rationalizing. I don’t want to be soothed into being less outraged at the dams.

  3. Doryfun Avatar

    Thanks for that info, you are certainly a good digger, and me too lazy (other irons) to google the universe.
    I never did like the hatchery system mitigation program, and maybe it isn’t wise to bite the hand that feeds you. However, if one believes in the 7th generation philosophy (which I do) then so bite the hand.

    Having attended the very first “ground zero” dam removal hearings in Lewiston eons ago (or so it seems now), I found a lot of things quite telling about representation of the two worldviews by the two cultures at the meeting. The Nez Perce sat in a circle beating a drum to the tune of Mother Earths heartbeat, while the dominionists played loud raucous music blasted over giant speakers in an attempt to drown out everything else.

    I also remember the general concensus of the NP was that they just wanted fish. Once they could see that dams were not going to be on the table, they decided to do something about it (kind of like the fisheries biologists at ground zero when dams first went in on the Columiba – doing something, was better than nothing was their thinking and resulted in hatcheries to begin with).

    The memory you speak about, is amazing when you think that science does indeed show that fish return to within 10-15 feet of the very spot they were born. Considering the thousands of miles these fish travel in fresh and salt water is an outstanding feat.

    I don’t blame the NP for pursuing such a course, and support that effort, as long as we continue to resist Snake River breeching. For awhile fisheries biologists gave an 80% chance of thumbs up for wild fish, by breeching the prescribed Snake River Dams. With the passage of time, I’m not sure if that number still holds. (foot draggers like Larry Craig are probably smiling over that – principled by once fish are gone, so go the worries).

    That the nutrients carried back by salmon that the establishment finally got around to realizing and thus allowed us to put dead fish back into the waters where they came from (instead of dumping disgracefully into landfills), has been recognized for sometime now. However, your theory about the tree problem as it related to the nutrient one is an interesting one to ponder. Thanks.

    I keep hearing the combative participants battling for potential presidency claiming how this nation is the best one on earth in the history of mankind. Yet we continue to rub nature raw, investing into projects while leaving natural capital out of the equation, dominating everything artificially (dams/hatcheries) to maintain our supremacy.

    Is there any wonder we are where we are, when you look at our dishonorable means (use of treaties as the legal tool of manipulation) to grab these lands to privatize and do what we can with them?

    1. Salle Avatar


      I agree. The first study that I saw on the nutrient depletion in the upland forests of the Rockies, though the study was conducted in either WA state or Canadian waters, it was a while back… I know I read it in a journal entitled “Fisheries” in the Jan. issue of either 2000 or 2001 (I’m leaning on the 2000 issue for the first place you might check if you want to read it.). In fact, I cited it during my comments to a panel conducting public outreach hearings on the issue of breaching the four lower Snake River dams back then. It was an event heavily attended by the tribal folks. The thing that got me was how the tribal folks got to testify first, and they gave those gov’t folks a mouthful of “shame on you for betraying the promises you made to us and our elders” and “we have been here for thousands of years and things were fine until you guys showed up” comments. (There were a couple hundred of them, I don’t think I’d seen that many NAs in one place outside of a pow wow.) But when they were done the “irrigators” from upper SE Idaho got up and whined about how they were third generation farmers and the land and water was theirs and they had all the rights in the matter.

      When I got up to the mic I stated with asking the panel if they heard anything the NAs had to say. I identified myself as a third generation American and then proceeded to this the philosophy to the Fisheries article (study)… all in three minutes. The court reporter who was taking down the testimonies, as I saw later, must have been hard of hearing or something because when I saw what she had down as my comments, they were incoherent, made me sound like I didn’t know how to speak my first language. I should have used the recording booth that was provided for overflow comments, to record my comments. Lovely. Obviously we were soundly ignored by the panel and the “deciders”.

  4. Doryfun Avatar

    I remember at the first hearings, Otter got up first to tout how he represented all the people of Idaho, shortly there after he left the meeting. This didn’t escape notice by an astute Nez Perce who later commented at the mic how he had noticed that our leaders do a lot of talking, but don’t stick around to hear what their followers have to say. (one of the tactics of a dominionist representing only one interest).

    Passing a pipe around the circle allows everyone to speak and listen to each other at the circle. Too bad too many leaders choose not to sit in the circle.

    Regarding claims to generational upsmanship, I have a favorite quote posted outside our shop in reference to fishing issues:“ An (eastern Washington) farmer came in and told me how hard his grandfather worked to make a homestead three generations ago, and how things could go belly-up if the Snake River dams were breached. I told him about my grandfather, who worked the same hard way to make a living fishing the Columbia, and he was a 700th generation fihserman. My grandfather went off to fight World War II for this country, and when he came back he found his business underwater, flooded by the federal dams.” – Donald Sampson, fish biologists Umatilla Tribe, OR.

    PS – I had to find this quote by googling – and discovered it on one or our old salmon posts on this site (I knew this same discussion touched some cobwebs in my head, as my memory is not quite like that of a fish).

  5. jdubya Avatar

    Salmon have amazing responses to catastrophes. The Missoula Floods that scoured out the Columbia thousands of years ago probably killed all the down stream salmon runs in the Columbia. But salmon and steelhead have this intriguing lack of fidelity such that about 10% of the fish swimming back up stream go someplace else. This is how neighboring drainages can, over time, repopulate damaged drainages.

    The key, of course, is having genetic diversity in the whole population and not losing it by constant inbreeding of hatchery broodstock. The very interesting finding of this paper was that hatcheries imposed epigenetic changes in the steelhead after just one rearing in the hatchery (certainly not enough time for any loss or change of genetic material) that altered their breeding behavior in the wild. That, to me, was very shocking.

    1. Doryfun Avatar


      Agree, the one generation thing is pretty astounding. Ya, I have heard that wayward adults spilling into other drainages was a survival mechanism, did’t know that it was that high (10%). I new that these fish were like heat seeking missles, often going up the wrong drainages then back down, to correct and eventually reach their natal streams.

      Regarding the Big Floods, having been on a few trips with Loren Davis (Archeology prof OSU, now) whom did his dissertation on the Lower Salmon River, and continues an on-going study there, found some things that I found most interesting. Like, no anadromous bones in many of the older middens. ( dating back 10000-13000 yrs ago)at least so far. Not thoroughly conclusive evidence, but spectulative anyway.

      Am curious,if you don’t mind my asking, what is your background? You seem quite knowledgable in fisheries.

      1. jdubya Avatar

        professor of mouse genetics and immune response…..nothing about fisheries except outside interests….

  6. David Avatar

    Has anybody seen this article? Scathing and terrible if true report on the fish restoration plan for the soon to be rewilded Elwha River in Olympic National Park. Restocking with genetically inferior hatchery fish seems like a bad idea. Apparently there will be pending litigation. Anybody got thoughts?


  7. Eliza Patt Avatar
    Eliza Patt

    An energy plan not determined by free market economy would go a long way. Late 70s politics anyone?


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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