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Salmon return to lay eggs in historic habitat after dam removal project (www.opb.org)
287 points by gmays 10 hours ago | hide | past | web | 205 comments | favorite





>Less than a month after four towering dams on the Klamath River were demolished, hundreds of salmon made it into waters they have been cut off from for decades to spawn in cool creeks

Do we understand the mechanisms of this "genetic memory" (my words, no idea if its accurate or if there is a better word for it)? Butterflies knowing where to fly even though it was their grandparents that last did it - eels traveling thousands of miles to breed in a place theyve never seen - countless bird migrations - even something as simple as how it takes a human baby 12-18 months to walk but many animals walk as soon as they are born. I would love to understand better how this knowledge is inherited


Salmon have no "genetic memory" - if you release baby salmon from a hatchery that were bred from adults caught elsewhere, they remember where they were released- not where they are genetically from-, and swim back to the area of the hatchery. It appears to be regular memory learned from experience. It is believed to be mostly chemical sensing, e.g. specific smells that they are remembering and returning to.

Salmon are not 100% effective at making it back to their birthplace, and some small fraction stray randomly- which is what allows them to populate new areas and re-populate others where they were wiped out. This article isn't about a lot of salmon - only hundreds, so this is probably the amount that would naturally stray to this region from others, with or without a healthy returning population.

For example, some ~120k chinook salmon returned to the Columbia river this year, so if 0.01% of them strayed to the Klamath river, you'd get about this many.


Salmon have also displayed possible geomagnetic navigation capabilities, similarly to homing pigeons.

https://royalsocietypublishing.org/doi/10.1098/rsbl.2017.075...


This is how sea turtles do it, too, and why sea turtle release has to happen on the beach despite the higher risk of predators.

They get sand up their nose and calibrate based on the magnetism of the iron, iirc


If some salmon group had been simplistically "programmed" to go up these waters, they would have been trying and failing to go up the river during the entire time the dam was there and so likely wiped out as a group/subspecies.

It seems like the fish would have to have had some kind of way to test if the river lead to adequate spawning grounds. And if they had that, they wouldn't really need any memory of any given river.


Looking at salmon research literature I found a study[0] with the following conclusion:

This study provides convincing empirical support for fine-scale local selection against dispersal in a large Atlantic salmon meta-population, signifying that local individuals have a marked home ground advantage in reproductive fitness. These results emphasize the notion that migration and dispersal may not be beneficial in all contexts and highlight the potential for selection against dispersal and for local adaptation to drive population divergence across fine spatial scales.

Seems like it might simply be that they go where they adapted to thrive.

[0] https://www.science.org/doi/full/10.1126/sciadv.aav1112


That doesn't really explain how they know to find this place, decades after the last time any member of their species visited it. It explains why evolution selected for this behavior, but the more interesting part is how it happens in an individual salmon.

>That doesn't really explain how they know to find this place, decades after the last time any member of their species visited it.

Because that's not what happened. These fish managed to get there because it was a good place for them to go, not because they were 'returning' to a place they had been before. The 'return' in the title is more about the fact that they are coming back to fill a niche in an area fish were blocked from, not that these specific fish were returning to a place they had been before. It almost seems like they were intentionally muddying the waters with the language used.


Clearly, the story that salmon go back to spawn and their birth pool is not 100% true

This is total and complete speculation, but possibly some sort of genetic or epigenetic driven system favoring some sort of chemical gradient/fingerprint unique to each river, maybe?

In order to survive, you wouldn't want to be wiped out if your home stream vanished. You'd want at least the likely chance of going to another stream to spawn and breed. Probably the salmon just swim upriver when they want to spawn. And it happened to be that now the Klamath is open.

Yeah, there's clearly tendencies for the fish to return to where they were born. I'm sure that's driven by all kinds of complex genetic memories and probably more importantly selective advantage due to adaptation to the specific characteristics of the given stream, but genetic memories for a specific stream seems a little bit unlikely.


> a large Atlantic salmon meta-population

I don't think this finding is necessarily relevant here, because Atlantic salmon are totally different. Pacific salmon always die right after spawning. Atlantic salmon return to the ocean after spawning, and will often spawn multiple times.


This news is about the end of a dam removal project. I believe this is also the end of the oldest dam removal project. The Klamath and IIRC the local tribes were the original test for salmon restoration/dam breach projects in the PNW, and subsequent programs are copying their success.

One of the things that makes salmon ladders more effective is introducing artificial noise of falling water. Turns out when salmon find themselves in still water they head for the sounds of the inflow, which dams either don't have, or are from spillways that the salmon cannot navigate.

Most salmon want to go back exactly where they are born, and on a three year cycle (or at least, that's the pattern on the Klamath). So if you were to introduce hatchery salmon in 2024, in 2027 and every three years after you'll have a full run, and only a small number of fish in the remaining years. Which probably isn't good for genetic diversity. So you end up having to stock at least 3 times, or just wait and see what happens.

NOAA page listing the history of work on this river (could use a timeline):

https://www.fisheries.noaa.gov/west-coast/habitat-conservati...

Whites Gulch Dam, ca 2008:

https://www.fisheries.noaa.gov/feature-story/building-networ...


these are hatchery fish; they were born on the klamath and they're returning to it. the only difference is that now they can make it to tributaries and spawn naturally, instead of being collected and having their eggs harvested and fertilized by humans back at the hatchery

There could be an environmental feature they prefer in that spot.

Edit: the article mentions lower concentration of harmful algae and a cooler temperature.


But then how are they aware of those conditions Also, the preference usually is more on the side of where they're born vs optimal proper placement

Nice water flows downstream, terminates in the ocean. They simply follow it back upstream.

I’m with you on this. Found some tasty water? Swim towards it. It gets tastier the further we go? Keep going.

So how do they find the river outlet into the ocean? There surely is some bird compass thing involved. I am only half joking when I write that Venus guides them.

That nature works at all is astonishing.


Yeah, no need to make this complicated.

Thanks, I was bang my head on this one, until you suggested a nice simple solution

The book Bird Sense by Tim Birkhead covers birds’ magnetic sense in Chapter 6. Research has demonstrated that seabirds have a magnetic map and compass that they use to navigate home, but it doesn’t discuss how this knowledge is inherited.

I believe Salmon use a similar mechanism, but it might be supplemented with chemical signatures. For Salmon, it’s possible that they genetically inherit the capability but learn the location at birth.


> seabirds have a magnetic map and compass that they use to navigate home, but it doesn’t discuss how this knowledge is inherited.

It’s not something that was decided by one ancestor and then inherited by everyone else.

It was something that certain birds had a tendency to prefer. Those birds thrived and reproduced at a higher rate, while birds without that preference presumably found less suitable homes.

It’s just natural selection and normal genetic variance. Some offspring every year will be born with slightly difference preferences due to the influence of various genetic differences. Some of those differences will be more beneficial for finding a good “home”, others less so.

There was a recent report of a very confused penguin showing up on a beach far from their normal habitat. Apparently this happens every once in a while. Those cases did not win the genetic lottery (though hopefully it made it back to a more suitable climate)


For animals like seabirds, a big part of the location could be non-genetic, as birds have different home roosts.

I would add that there can be many local maxima, so it isnt always about finding less suitable homes. Birds of the same species can have different homes.


Salmon do use magnetic senses to navigate the oceans as well, but it is an acute sense of smell (among other things) that allows (most of) them to return to the headwaters of their birth.

None of those salmon were born there because the Damn was in the way

I was also curious about how a popular beaver [1] was raised by humans and "instinctively" knew how to build dams.

[1] https://www.youtube.com/watch?v=DggHeuhpFvg


It's not a genetic memory. They return to the place they were born. This is probably based on the "scent" of that place, and maybe other factors.

Some percentage either accidentally or deliberately go up a different river, which is how the species spreads. That's very likely who this story is about.


I think the point is if they "return to the place they are born" then why would they go back to the waterways freed up by destroying this damn. Clearly they have some heirachy in where they prefer to spawn and this place is at or near the top, or they would have opted to return to where they were born

Most of them go back to their birthplace, but some end up elsewhere.

If that's a "deliberate" evolutionary strategy or just that 100% navigation success doesn't happen is unknowable.


Might just be some kind of salinity thing. Upstream -> Less minerals dissolved

My 100% speculation is emergent behaviour from the brain itself. Same way human interactions have remained largely the same over thousands of years. Also, we don't notice the salmon that swam up dead ends elsewhere.

> Do we understand the mechanisms of this "genetic memory"

I don't think there is particular evidence for "genetic" memory here. The salmon were already further down river, they just kept swimming upstream. While most salmon do return to the place of their birth, a small percentage always stray, which is how salmon are able to colonize new habitats and survive things like ice ages.


>While most salmon do return to the place of their birth

I wonder to what degree that is even true. Like sure they probably return to the same rivers, but how far up the river they swim is likely unrelated to where they were actually born. If you extend that river further or introduce side streams that didn't exist when they were born, they're probably just as likely to end up in one of those places.


Exactly that. They also need the right kind of gravel to spawn in. The kind you find in mountain streams.

Glad they are doing well.


Human babies physically cannot walk. It’s not merely a knowledge check.

Pretrained brain modules aren’t the most surprising thing. Humans have plenty of pre trained behaviors, some of which kick in a while after birth.


> Human babies physically cannot walk. It’s not merely a knowledge check.

They physically cannot walk, but they also don't know how to. We know this because they need to practice and acquire skill. If they are deprived of opportunity to learn but their body continues to mature, their mature body does not give them the mature skill.


It may be that humans practice things, but they’re still mostly pretrained capabilities that activate. Most of walking and balance is subconscious and not “learned” via experience. We have dedicated neural hardware for this.

Language processing is another example. There’s dedicated neural hardware designed for this specific task.


Are you saying that a human left to their own devices would not eventually walk? That walking erect is mimicry?

I think they’re saying a human that was not able to practice walking would not be able to walk even if their muscles were fine; like an inverted Neo waking up from the matrix.

It’s hard to imagine it being possible to test but I think they’re wrong.


That's why I'm asking to clarify what they meant. Because from observing how quickly other animals (including other apes) acquire motor skills from birth, I don't see why we should attribute walking to a practiced skill for human infants, rather than a physical sturdying of their body to sustain the activity.

Practice itself is an instinctual behavior.

Evolution isn’t limited to direct methods, as long as it works that’s enough.


I never crawled. My parents were worried, they went to doctors who assured them that I was mostly alright, and then one day, I got up and started walking.

I saw the exact same behavior with my ex-gf's sister's son, who we took in after he was in foster care from birth. The child had clearly not been engaged with properly... the back of his head was bald because he was always on his back in a cramped bassinette and at 11 months he hadn't even learned to turn over. Within 3 months of being with us, he was walking.


The simplest answer in this specific case is that there is no genetic memory involved, and salmon will just swim upstream into any fresh water stream they come across.

Could be very very simple.

Swim until you can't anymore?

Swim until the current is very weak?

Swim until the water smells/tastes nice?

Someone could probably simulate these and see which matches reality the most.


> Do we understand the mechanisms of this "genetic memory" (my words, no idea if its accurate or if there is a better word for it)?

It’s not actually a memory that gets encoded in genes.

It’s a tendency to behave in certain ways as influenced by combinations of genes

Ancestors who had the same tendencies, drives, and preferences would have some similar behaviors, resulting in some of them going toward the same places.

So not an actual memory that gets inherited, more like personality traits (but in a more general sense) that lead to similar outcomes.

There is a field of epigenetics which studies heritable changes in cells that occur without DNA alteration, but these signals are much simpler than memories and not a mechanism for carrying memories across generations. A lot of pseudoscience has been written around epigenetics right now so you have to be careful about where you source info on this.


> how it takes a human baby 12-18 months to walk but many animals walk as soon as they are born.

This is because humans are born with, comparably, extremely immature brains. The animals that can walk after birth are born with more mature brain development than humans are born with, so they are capable of walking.

https://www.livescience.com/9760-study-reveals-infants-walk....


It's not completely brain development, look up the stepping reflex in human babies. Humans are just as neurally pre-wired to walk as foals are on day one but we're also born long before we're anywhere near strong enough to do it, it takes at least another 6 months of physical growth and strengthening out of the womb before babies even try.

sure - but how did a horse foal learn how to walk within an hour of their legs being in contact with the ground? Or even for human babies, how are they hard wired to search for milk or even breathe?

Humans and horses don't share the same evolutionary pressures. A foal gets eaten if it can't walk right away, we don't. Evidently our super brains are worth all the hassle. Unsatisfactory answer, maybe.

>>or even breathe

The same way your heart "knows" how to beat - it's a lower level function that happens without your conciousness. That's why people who are brain dead still live and breathe and swallow and digest and their hearts livers and kidneys still do their job.

>>how are they hard wired to search for milk

The ones who didn't died, to put it bluntly. Obviously not human babies, this evolutionary step happened long long time before the earliest hominids.


> same way your heart "knows" how to beat - it's a lower level function that happens without your conciousness

Heart cells in a Petri dish will happily beat away.


That isn't an explanation of how it works.

This is kinda like explaining how a car works with "you fire and replace engineers until it moves".


totally - but to be clear the question I have is more like "where in the body is this knowledge encoded (for lack of a better term)"

Do you have neurons in your brain that are pre-wired for these things? Is that encoded in your DNA? Like physically how is it inherited and the selective pressures applied?


Yes, yes, and you got it. Largely it’s DNA that controls development of neurons/muscles/etc. that mediate nursing, walking, and so on.

On selective pressures: human babies that aren’t born with the ability to nurse, or foals born without the ability to walk—because their in-utero development didn’t allow it—historically don’t survive, and thus don’t reproduce.


I think it's a chemical structure reacting to an energetic stimulus.

> even something as simple as how it takes a human baby 12-18 months to walk but many animals walk as soon as they are born.

That's just a matter of muscular development. Human babies are born early; I believe this is usually attributed to the difficulty of getting the head through the birth canal.


The story about eels is especially fascinating. I was told in my fishing course they can even get across small patches of land to continue on their journey. I did not bother to fact check it though.

I’d assume that evolution in salmon is just not fast enough to catchup with the dam.

EDIT: I don’t mean that as a joke. I think on the timescale of evolution the dam was never there.


Ok but the first generation to hit the dam died there and had no offspring. Any salmon spawning in these streams have no connection to pre-dam salmon.

Right. But their genes do.

You assume: hit the dam > died.


I know it's going to sound like a bunch of hooey, but information really is the most intrinsic element of all aspects of this universe, especially when it comes to life. The life force is a thing that is interrelated with our physical bodies, but is not the physical body. It's just like the zen concept of "Not 2, not 1". Our minds have the same relationship with our brains. They're not separate, they're not the same; they're interrelated.

That we can't "see" the other side of the connection with our science is due to our science being built with our physical world's constituents (matter & energy), thus those other dimensions are immeasurable with our science's tools. Rupert Sheldrake speaks of this when he says that the genetic code's protein construction genes do not and can not account for the resulting organism's shape. That coordinated construction requires a separate guiding force. That interrelationship is similar to the "memory" that creatures such as salmon have, which is intrinsic to their entire being, not just their physical body, which is only half of our being's totality.


what you're saying is basically untestable and that's why most scientific minded people only talk about such things over beers or dismiss it entirely. It's not unlike religion or crystals. I mean we can't necessarily disprove them as they are based mostly on faith in an untestable conclusion.

I suggest that our universal resistence to such ideas is the result of a concerted effort upon our minds and hearts to convince us to embrace selfishly ignorant foolishness rather than selflessly wise service.

There is talk here on HN about mathematical reasoning but no one talks about how our systems would affect the Earth differently if we used compassion as our modus operandi instead of for-profit plundering of the Earth for selfish profit. That is because selfishness is our default state -- an animalistic state -- and we must choose to transcend it by self-evolving ourselves beyond our selfishness, and into humanitarian systems that cooperate instead of compete.

If you wish to find out how to know the truth in your own subjectively objective reality, browse my other comments. You have your own internal connection that allows the unlocking of your full human potential. Becoming consumed with compassion is a necessary part of that transformation, but we are each free to choose selfishness, and, indeed, most have and are choosing the selfish path. That selfishness is behind every single atrocity ever perpetrated, as well as the spoiling of the Earth for our future generations. For people that choose to become better, the changes come slowly and with drawbacks, but with all art, perseverance and steady effort to improve is the key to success.

We each have the power to rise above that animal selfishness and instead choose to design societies of compassionate service to one and all. That path of love is our only hopeful path forward.


If selfishness were our default state (as you state) no baby would ever be nursed. No wounded person would be treated. No missing person would be searched for.

There are degrees; complete sociopathy is unlikely because it defeats self-preservation. Most people are mostly selfish towards out-groups. But, yeah, some mothers are really selfish.

Whether or not this is “true,” it’s not explanatory.

Someone asked how a thing works, and the answer above is essentially just restating that it does in fact work, for some ineffable, immeasurable reason.

So while interesting to think about, it’s not a useful response to the question.


We understood that Mercury's orbit was wrong per Newton's laws long before Einstein came along to explain to us why.

Whether or not something is true is always the beginning of a scientific exploration.


Of course, but if we don’t know how something works, it’s ok to just say “we don’t know yet.”

There may in fact be physical, measurable mechanisms that govern these types of animal behavior. Just like there was a physical, measurable explanation for Mercury’s orbit.


Yes, but it was Einstein's imagination that provided the theoretical framework that allowed the longstanding physical measurement to line up. If his imagination was limited by Newton's laws, he would have never come up with GR. If he had said that mass causes time to vary, he would have been laughed out of the room, with much ad hominem shouting.

What I'm saying here is that we need to push beyond our current scientific paradigms to find out how these inexplicable corner cases actually work. As well, I do realize that the depth of exploration required will be further than most people are willing to plumb, which is demonstrated by the in-their-feelings reactions to my ideas.


And now dark matter is throwing a wrench in Einstein’s stuff. Like Newton’s laws, Einstein’s stuff gets is mostly right (impressively so, even!) but breaks inside black holes and doesn’t seem to exactly line up with what we observe about what keeps galaxies in tact.

And I’m sure whatever we discover that “solves” for dark matter will eventually start showing cracks as well, prompting another deep inquiry into the nature of our universe.

Good times.


5/6ths of the universe's matter is missing, or thereabouts. That fact aligns with there being six vibrationally distinct dimensions in our 3-space (our physical dimension being just one of them, our soul inhabiting its counter-dimension, all things in our universe having been created in pairs). The matter/energy from each dimension are distinct, so we can't detect the others using instruments made with ours, yet -- somehow, I don't know how -- the mass combines to contribute to the gravitational inertia that keeps the galaxies from flying apart.

That said, when we slam particles together at high enough energies, we do see crossover (briefly) in the form of anti-particles. I couldn't begin to explain the mechanisms behind this, but the structure can be known to seekers of compassionate existence. This is also a hint to the solution to the question of why, after the Big Bang, we don't have an anti-matter left; the answer is that it's where it is, but that we can't detect it with our current tech (or maybe any tech, for all I know).

The universe was made to be known by we human beings, we being the information processors designed to work in harmony with this information-theoretic universe, which is fully queryable by a suitable trained mystic.

A Sufi Murshid (teacher) lived his entire life in a single town that consisted of a single pair of roads that met in the center of town. Late in his life, he stated that, he "knew the stars of the Milky Way better than he knew his town". (A love-consumed mystic remains conscious as our souls leave our bodies when we sleep. What is called astral travel is not limited by our physical body's speed laws; it is bounded only by the "speed of thought".)

Sufi stories are glimpses of corner cases meant to spur us to push past our "known" boundaries. We need to get this world at peace before we can explore our advanced abilities. As Louis Armstrong said, "If lots more of us loved each other, man, this world would be a gasser!"


> Rupert Sheldrake speaks of this when he says that the genetic code's protein construction genes do not and can not account for the resulting organism's shape. That coordinated construction requires a separate guiding force.

Of course there's a separate guiding force. It's the biochemical environment around the cell. Cells operate on chemical signals they receive from their environment and generate the same; these cause cells to differentiate themselves based on their genetic code, which where the resulting organism's shape comes from. This isn't some kind of mystery, we know how this works, and matter & energy are indeed sufficient to explain it.


> Rupert Sheldrake speaks of this when he says that the genetic code's protein construction genes do not and can not account for the resulting organism's shape.

> That interrelationship is similar to the "memory" that creatures such as salmon have, which is intrinsic to their entire being, not just their physical body, which is only half of our being's totality.

This is all pseudoscience and borderline religious thinking. Rupert Sheldrake and others pushing this line of thinking are not grounded in reality or science.

I’m surprised this is the most upvoted sub comment at the time I’m responding. Is pseudoscience like this really becoming so pervasive that comments like this pass as good information?


Well, when your science explains where the 5/6ths of the missing matter in the universe is, or where the "dark energy" is, I'm all ears.

Also, you can try to explain how individual proteins arrange themselves into bilaterally symmetrical, organ-infused organisms of astounding complexity, using only protein recipes.

I know you can't explain it, but that doesn't mean you won't try.

There is the known, the unknown, and the unknowable. For many, entire branches of the unknown are unknowable because they refuse to expand their criteria for how they evaluate the facts. Sherlock Holmes' father had a quote to the effect about once you have eliminated the possible, all that's left is the impossible (bad paraphrase, I know).


That’s beyond bad paraphrasing - that's the polar opposite of the original.

When you have eliminated the impossible, whatever remains, however improbable, must be the truth.


Thanks for that. I stand corrected.

But my comment was geared towards those who believe that what I am suggesting is impossible, so to them, the only possibilities left are what they consider impossible.

My favorite quote from Holmes is the slightly modified one in Jeremy Brett's version of "The Naval Treaty":

"What a lovely thing a rose is. There is nothing in which deduction is so necessary as in religion. It can be buit up as an exact science by the reason. The highest assurance of the goodness of Providence seems to me to rest in the flowers. It is only goodness which gives excellence, and so I say again, we have much to hope from the flowers."

[The entire high-def Jeremy Brett Sherlock Holmes tv show series can be found on YouTube.]


> Also, you can try to explain how individual proteins arrange themselves into bilaterally symmetrical, organ-infused organisms of astounding complexity, using only protein recipes.

The problem is that you’re conflating “I don’t understand it” with “it must be magic”

A hallmark of charlatans and pseudoscience pushers has been to find something they can claim is the boundary of scientific knowledge (often incorrectly) and then assert that everything past that line therefore is magic.

It’s a tale as old as time. Yet every time we make new discoveries they just move the line a little further and claim the magic must be over there now.

Another classic move is to make extraordinary assertions (magical hidden forces) but then when anyone objects they try to push the burden of proving the opposite on to the other person. That’s something you’re doing throughout this thread perhaps with realizing how irrational it all is.


This is a bunch of pseudoscience that isn't proven by anything at all and isn't peer reviewed either

And your proof that it's wrong is ... ?

That would make your counterargument a pseudo-counterargument, no?

It's just reaching into one's feelings/nether-regions and blabbering out some words.

You don't even have a sensible counter-theory, right?


The vast majority of possible explanations for anything are wrong, so "correct unless disproven" is not a sensible default. Your evidence that it's right is ... ?

I can't provide what is, by definition, subjective proof. You must seek and find it yourself, in accordance with our shared universe, which has the same interface with you as it does with me. You could not look at me and comprehend the truth of what my life's choices have wrought upon my being, the happiness my family experiences, even within our poverty. No, you surely can easily deny that as well, and it is your free will's ability to do just that.

But it is also within your potential to treat me better than Eugene Parker's or Boltzman's contemporaries treated them, and instead keep an open mind and open heart and follow the path laid in front of us all that allows us to cure ourselves of our destructive selfishness and begin a new path forward.

If you look through my other comments you can find a more detailed description of the key that unlocks the necessary doors, and with them our latent abilities, which include knowing instead of just thinking.


Animal behavior usually has a weird combination of inborn instinct and learned behavior.

The one I've read about that stuck with me was dam building by beavers. Some part of the behavior is driven by a dislike of the sound of running water. Someone did an experiment with speakers playing the sound of running water and the beavers near the speakers would attempt to cover them with sticks and mud.

In my head I'm imaging that sound is like nails on a chalkboard to beaver.


Instinct shows up locally as emotion. An individual animal acts based on their emotional state, and their emotional state is governed by a set of rules deep in their brain of which they are not conscious, many of which are set by birth.

This is true of humans as well. We each make food selections based on what tastes good. We seek particular sexual partners because it feels good. We protect and raise kids because it makes us feel good to do so.

This causes all sorts of evolutionarily weird side effects like people treating pets like kids in order to access the same emotional state as parenting. Or beavers covering speakers with mud and sticks.


evolution uses whatever hook it can find to tune behavior. Brains of sufficient complexity have to learn, you can't fit even enough information in DNA to manually wire up a brain, and its hard enough to guess how a barin will end up being wired. you can attach a squirrels optic nerve to their auditory cortex and they'll learn to see. (I may have the animal wrong). You can grow a brain completely inside out that will function.

Instincts are deterministic, but learned behaviors.


"Dislike" may be an anthropomorphism. Perhaps it's more of an opportunity for the beavers, since dams are their habitat and provide a food source for them.

yep it could be just as likely that they enjoy building the dam whenever they hear water. seems much less stressful on the system

Evolution doesn't mind how it feels, it only matters if it's effective at adaptation. It could be that running water in their homes stresses them as much as it stresses us, albeit for different reasons.

The running water speaker experiment was done in dry land, and beavers are very wary of going out of the water because of their predators, yet they risked working over the speakers.


Maybe that's a thing, but here's a video of a pet beaver making a "dam" out of stuffies and other household objects.

https://www.youtube.com/watch?v=-ImdlZtOU80


I like the sound of running water from a fountain. But if I hear it inside, I assume there’s a leak and I go looking for it to fix. Maybe the beavers just need to visit the zen garden.

Not a beaver, but close: an otter wreaked repeat havoc in the Sun Yat-sen botanical garden in Vancouver, eating many valuable koi:

https://vancouversun.com/news/local-news/the-godf-otter-part...


Probably the best use of 45 minutes on youtube, I've watched it 4 times now and still love it every time: https://www.youtube.com/watch?v=aDbIAy9sMHk (doc on beavers)

FYI the podcast Gastropod did a really good episode on the dams & the salmon

[1] https://gastropod.com/bringing-salmon-home-the-story-of-the-...


Lots of discussion about salmon memory and such, but is it possible this is just Salmon finding "hey this is a great spot"? It is hard to imagine salmon not being flexible to some extent, and still surviving.

Salmon are also making a resurgence in some areas where storm water runoff is being controlled and filtered. A chemical in tires to prevent cracking is lethal for Chinook and Steelhead, so keeping that out of watersheds could create huge population increases due to the amount of eggs. "6PPD-quinone, that is deadly to coho salmon at extremely low concentrations and is often found in urban streams. Stormwater run-off from roads kills both juvenile and adult coho within a matter of a few hours. Even stormwater diluted to a mixture of just 5 percent highway runoff still killed juvenile coho, the new research found." https://www.fisheries.noaa.gov/feature-story/roadway-runoff-...

Yep... also add the "let's go up the river as far as we can, and we'll find a nice spot somewhere over there".

Sometimes young Moose from the north run past the mating grounds through excitement. They end up in my neighborhood for the season and then run back north.

Well, maybe this „find a nice spot“ search function is the „memory“ that’s encoded in genetics.

It's already been established that a sense of smell is vital in Salmon's ability to return to the headwaters of their birth. I'm not aware of any "genetic" component, it is simply that Salmon remember the smell of where they were born and most salmon try and return. The feat is amazing and there are many "instinctual" behaviors involved, but no evidence that there is a genetic heritage from a specific headwaters is important in returning to that headwaters.

This "genetic memory" talk is just uninformed people jumping to conclusions and spreading speculation as fact.


I’m merely proposing a mechanism for how it could be possible to have salmon return to the same spot after several generations, if that actually does happen.

The idea would be that a salmon could be genetically predisposed to follow a certain path, perhaps preferring the smell of a certain combination of chemicals, thus encoding the location. It means the „memory“ would be encoded via genetics as a result of genetic combination and mutations, and the „encoding“ would essentially just be selection. It’s just speculation on how this genetic memory idea could work without actually encoding memories on genes.


I read a fascinating article on this dam removal last week! https://hakaimagazine.com/features/the-other-side-of-the-wor...

The article tells both sides of the story of the dam removal in as fair a way as I think is possible. Many of the locals were against it and there was a strong advocacy group that fought for it, including a tribal constituency.

I came away from the article feeling I understood both sides better but with less certainty about what was the right choice.


Not a bad article, all things considered, but I do think it gives a shallow treatment to reasons of the objectors to dam removal.

How many people are impacted and how? Will they lose their businesses, jobs, and life savings?

The closest it comes is talking about the spotted owl, where 30,000 people lost their loverhoods without compensation due to an environmental regulation that not only failed to deliver, but was doomed from the start. What are the parallels here?


> According to PacifiCorp, the Oregon-based company that owns the Klamath dams today, the structures are mainly monitored and controlled remotely—from Lewis River, Washington, more than 500 kilometers away. Local jobs add up to 13, and all the affected employees either retired, voluntarily left the company, or will be reassigned within it.

from the link. probably a few more people in recreation indirectly affected, but these are small, remote reservoirs. It's not like we're draining Lake Powell here[1]

[1]: be still my beating heart


I was thinking more in terms of farmers and community along the river, people with lakeside land, and those downstream exposed to flooding, essentially wherever there opposition is pulling it's support from.

These are mountain dams, without meaningful irrigation or flood control applications, and dwindling hydroelectric utility. They impounded 3 reservoirs with a total surface area ~1/20th of Lake Washington, one of which has ~100 privately owned frontage parcels. Those owners lose their lakefront, but in a few years will enjoy views over and access to a river valley instead.

Well founded objections should be treated with respect, but I think there's a lot of resistance that's born of (a) reflexive opposition to the 'other side' (b) false generalization of dam-removal arguments applicable to specific dams to all dams, and (c) the incorrect assumption that existing dams must have some utility (equivalently, unawareness of just how many __useless__ dams cover the west, these Klamath dams among them).


People will believe and fight for literally anything, surely thousands of years of con men has taught us that. The fact that this guy with a whopping 4 generations in the area doesn't agree means next to nothing to me.

The point isnt that some guy doesnt agree, it is the ideas and information they are communicating.

A lot of the local opposition to dam removal is because of this guy specifically. Here's his article on why the toxic cyanobacteria that was in the former reservoirs is actually good for the river:

https://www.siskiyou.news/2024/01/24/blue-green-algae-in-cop...

It pretends to be a regular news site, and even "scientific", to the point where it fooled Google and his site was often at the top of search results. He was also aggressively promoting his articles on Facebook.

The guy is confusing green algae with bacteria. He's also ignoring the fact that the kind of blue-green "algae" in question, Microcystis aeruginosa, isn't the nitrogen-fixing kind. He has no clue was he's talking about, but that doesn't stop him, and he's unfortunately a major source of "knowledge" (confusion and misinformation) for the locals here.


> Resistance to dam removal on the Klamath is emblematic of the profound mistrust of official narratives that increasingly leads to such upside-down outcomes as survivors of climate disasters denying climate change, or rural communities accusing the wildfire fighters who protect their homes of deliberately setting the fires. Reservoir Reach is a place where, if KRRC is using helicopters to prep for dam removal, it must make sure the public knows that the choppers aren’t carrying out black ops against American sovereignty on behalf of the United Nations.

The author seems to have developed quite a strong bias about the area.


What about that statement sounds biased to you?

To my ears, that is a plain spoken description of the culture of the area, compatible with what I have observed myself over the years.


It seems like it is painting with an overly broad brush, condemnation by anecdote, and characterization by the negative extremes.

But then again, I have my own priors, which probably bias me to thinking these people have legitimate reasons to distrust authorities who view their lives as expendable.


We must have completely different experiences, then. What years and where were you active in the is area? I’ve been visiting for over a decade doing hiking, fishing, spelunking, etc. Every town had tin hatters, but to paint the whole town like that is certainly extreme.

All these dams on the Klamath river did have fish ladders where the salmon could go upstream and spawn. Removing the dams just increased the number of fish swimming upstream. Some of the fish ladders had glass walls and people could watch the fish going up & down the ladder.

This is factually incorrect.

From the 2013 department of the interior report discussing dam removal "Klamath Dam Removal Overview Report for the Secretary of the Interior: An assessment of science and technical information":

> In particular, the Klamath Tribes of the upper basin have experienced their 92nd year (period starting with initial dam construction) without access to salmon and have continued to limit their harvest of suckers to only ceremonial use for the 25th consecutive year because of exceptionally low numbers and ESA protection.


I don't think that's accurate. The remaining dams have ladders, but the lowermost dams had no (or inadequate) ladders, hence the total absence of salmon from the upper Klamath.

> Although the Bureau of Reclamation’s Link River Dam and PacifiCorp’s Keno Dam currently have fish ladders that will pass anadromous fish, none of PacifiCorp’s Four Facilities (i.e., Iron Gate, Copco 1, Copco 2, and J.C Boyle dams and associated structures) were constructed with adequate fish ladders and, as a result, anadromous fish have been blocked from accessing the upper reaches of the Klamath Basin for close to a century.

N.B. Keno and Link River are _not_ being removed.

https://www.fisheries.noaa.gov/west-coast/habitat-conservati...


This is completely incorrect.

I'm lucky enough to have a salmon-bearing stream on my property here in the northwest. They are an extremely inspiring species to watch through their lifecycle. Tenacious.

Growing up, I'd watch the run coming through the Ballard Locks. Phenomenal to see.

I'm surprised we could never engineer a proper salmon "elevator" to bypass the damn. Given the price of removing the damn, there seems to be a huge budget for creating some sort of high-tech Robo-elevator to scoop the fish out and drive them way upstream in a robo-vehicle.

Maybe a giant net that lies at the base of the damn, and periodically lifts out of the water to catch the fish and automate the transportation of them to ideal next step drop.


Fish ladders have been around for centuries. They have mixed results.

I went to Bonneville Dam on the Columbia River between Washington and Oregon and it was kind of like being in an aquarium watching the fish swim upstream. They seemed to get tired and would float backwards with the water current and then start swimming again against the current.

https://en.wikipedia.org/wiki/Fish_ladder

They also had a salmon hatchery literally right after the dam. But they had some stats showing that it also had mixed effectiveness.


Things like that have been developed

https://www.youtube.com/watch?v=2z3ZyGlqUkA


There are definitely ones that work very well. Ladders with just the right water flow and step sizes, chutes that whisk away fish in a tube, etc. As dumb as it sounds one of the more effective methods is having fish collect into concentrated tanks that are then trucked upstream to the right spot.

Trucking is definitely not an efficient way of moving salmon past dams: https://www.opb.org/article/2023/10/31/willamette-river-salm...

Then why couldn't they make that work for this damn? I'm assuming there must be other motivating factors for removing the damn.

It's not just cost of a retrofit. Like other structures, the utility of a dam depreciates over time. Unlike other structures, some of that is due to sediment accumulating behind the dam, not the facility itself wearing down. This happens faster than you'd expect - service life for a dam can be <100 years.

Maintaining the facility at full capacity means dealing with the sediment, not just the dam itself. For example, look at what LA County is having to do in the San Gabriels to maintain a damn we want to keep [1].

[1]: https://www.amesconstruction.com/project/san-gabriel-reservo...


One is surely sediment erosion. All the small gravel that would usually end up in the delta being collected behind the dam.

I.e like here: https://en.wikipedia.org/wiki/Restoration_of_the_Elwha_River...


Most of the Klamath dams were pretty old and not all that useful for other things like electricity generation or flood control, IIRC.

I drove through Klamath Falls yesterday... that storm is sure going to give the river a lot of water to work with. Yeesh.


In the article it says energy for 70k households. Not saying you are wrong but that is substantial.

It could power 70k homes at full capacity. Important note, it wasn't at full capacity, and the entire county of Siskiyou is only about 40k people (not homes).

Our power company, Pacific Power, said they didn't need the dam at all, and it would cost more to maintain than it was worth.


A lot of the dam removal pressure is activist not scientific - people who have come to believe dams are evil because they aren’t natural. Some of it is cultural - with upstream tribal lands where people cannot practice traditional life or activities like fishing without returning fish each season. Some of it is practical - we don’t do a good job maintaining old dams and new replacement projects are expensive. But I do worry that the new dam removal movement is sacrificing renewable energy and flood control and navigable rivers for little gain, when they could find solutions that keep the dams and help upstream environments.

Well designed ladders work efficiently. Fish don’t have to over exert themselves, make jumps (actual leaps to the next step) no bigger than they would naturally (with no dam), and have lots of resting spaces across the ladder where they can regain energy in gentle waters before continuing swimming and jumping upstream. They slowly gain elevation moving across spacious concrete tiers until they reach either a natural release point upstream enough that the strong flow into the dam doesn’t take them, or they end up in a hatchery.

I feel like hatcheries are underrated. Sure the upstream habitats are not the same without the fish and associated ecosystem. But if you have the right equipment, staffing, funding, and all that (basically a good government) the hatcheries could be made to churn out more fish than would be naturally possible. That’s because the trip upstream naturally is hard and many fish won’t make it anyways.


Ladders can be fine, but I think one has to accept that the cost:benefit of installing a good ladder at an old dam might favor just removing the dam.

Hatcheries, OTOH, are a poor simulacrum of a real fishery and a real lifecycle. They might churn out more juveniles than a natural river would, but that doesn't necessarily translate into a larger catch or higher quality catch.


Keeping the dam isn’t a ‘scientific’ decision because science doesn’t make decisions—it just tells us what might happen: more fish, less renewable energy, changes to flood control, etc. The real decision is about trade-offs, like how much we value fish versus clean energy, upstream ecosystems versus downstream economies, or cultural traditions versus infrastructure costs.

Calling dam removal ‘activist’ implies the push to keep it isn’t. But keeping the dam is just as much about advocacy—it’s about prioritizing things like renewable energy or flood control. Neither side is more ‘scientific’ than the other; they’re both driven by values. Science helps us understand the stakes, but humans decide what matters most. That’s why this stuff gets so messy.


Thank you. So many people confuse their own values with science. Science might say "If you take action X, thing A increases" and a person who values thing A hears "Science says we should take action X". That is not correct. Science informs you about the impacts of your actions (imperfectly), and it is a social/cultural/political (and most definitely not a scientific) discussion which of those impacts we actually prefer.

I think "activist" in this context is simply shorthand for "environmental activists" has a local/distant component, as well as a direct/indirect component to the impact.

There are thousands or millions of activists, statistically urban and distant, that like the conceptual idea of a free flowing river with salmon. Most of them will never visit the river. These are pitted against a much smaller number of geographic locals, many of whom may suffer flooding and the loss of their jobs, businesses, and retirements. This is not to say one side is inherently right or wrong- it is still a matter of values.

I thought the article could have done a better job of explaining what the locals realistically stand to lose in this situation, and less time on the conspiracy talk. In my experience, the conspiracy theories come as secondary post-hoc justification for economic and cultural interests of their adherents.

> Neither side is more ‘scientific’ than the other; they’re both driven by values

This isnt always the case. With respect to the science, sometimes different sides claim different and conflicting outcomes. The extent of the salmon run when it returns is a factual prediction, where one side can be shown right or wrong, as is the number of people who will be flooded or lose their jobs.

Towards the end of the article, it talks about spotted owl conservation, where 9 million acres of Forrest were protected, causing 30,000 loggers to lose their job. The environmental activists overstated how much this would help the owls, while the objectors held the position that logging was not big impact and the real driver was out competition from the barred owl. The aftermath showed the position of one side to have more scientific merit, but that is little consolation to those who had their lives destroyed. Inversely, the bad science has no cost to the conservation activists, because they had nothing to lose from the regulation.

This is a bit of a pet issue for me, because I have family who lost their life's work and life savings in similar situations.


No. Dam removal is driven primarily by practicality.

The environmental piece is a lovely bonus, but the truth is these dams are obsolete, end-of-life and will eventually fail. Leaving them in place is not an option, they either need to be replaced or removed.

Replacing a dam with no purpose is a waste of money, and the (ahem) downstream benefits of a healthier environment benefits both existing folk and improves land for future generations.

It really is a rare win-win situation.


But why? The cost of upkeep for the dams compared to the amount of utility they provided was already too high to preserve the dam. Adding this sort of mechansim would only add to the cost of upkeep, making the preservation of the dam an even worse proposition.

This is only tangential but with more solar and nuclear, more and more projects like this will become possible.

Here in coastal British Columbia, it’s the removal of ocean fish farms that has sent the dwindling numbers of pink salmon soaring again!

There are systems to allow salmon to go over dams. From ladders to cannons.

I hope they are right about this dam not needed for flood prevention. Spain just lost hundreds of people and suffered billions in damages because these kinds of policies.


Getting fish ladders to work where they exist, or built where they are lacking, is not an easy feat either.

And the dam removals in Spain have nothing to do with receiving 770 mm of water in one single day. None of the removed dams would have protected an area that was planned to get flooded when the works of the 1960s were done.

https://www.reuters.com/fact-check/map-shows-existing-river-...


I have a guy in my family who worked to remove dams over a small tributary river of the Seine, in Normandy, France. It took him several years to remove the 300+ dams, the oldest ones being easily 150 years old. The very first year after his work was completed the salmons came back.

Now he works in the environmental police, and is often called to handle cetaceans getting lost in the Seine delta. People freak out because it is an unusual sight nowadays, but he told me this is just a return to how things were. They are stories of dolphins swimming as far back as Paris in the past centuries.

I guess this means we're doing something right, I hope one day we'll be rid of this poisonous brown opaque water flowing through our cities. I really hope one day to be able to see this "clear water" my grandpa told me he learned to swim in.


Very clear water is dead-er than turbid water. Very clear water means nothing is living in it.

I do too - thank you so much to your relative for their important work.

Sadly, it seems like things are mostly going in the opposite direction


for the past few years i've been watching the salmon return to a spot in the uk they've not been to for over 200 years. i had no idea growing up there that these were salmon spawning grounds, then some wiers were removed. such a wonderful thing to see. i don't think it's memory!

Hopefully the Snake river is next.

Hydropower is the only true renewable green energy that we have. It's ironic that dam removal is so popular with people who claim to care about green energy and the environment.

I wish the environmentalists would make up their minds.

Either they want clean power from hydroelectric dams or the don't.


Well, if you looked into the subject at all, you'd learn that these dams are obsolete and don't generate much, if any, hydropower.

They were usually put in place before we had a power grid.


I'm most curious about how the salmon found it so fast.. Did their instincts predispose them to go there, if they were in the area? or was there some physical trace they were following? or is there some weird lamarkian genetic memory thing going on? .. In fact do we know now salmon normally navigate 1000's of miles back to their spawn location?

They swim towards where they feel water flowing from. They keep going until their bodies are breaking down. Fish at the spawn location often have rotting bodies, even as they still live - losing color and with their flesh changing consistency.

But what about at the start when they are in the ocean and water isn't flowing from anywhere in particular?

+ How do they end up in one particular river and not another?


That part is not really known. Various things have been suspected like memory of magnetic fields, salinity, temperature patterns, odors, etc. Basically they may be memorizing those on the way out and end up coming back to the same shoreline. From there it’s following upstream water pressure (which is how salmon ladders induce them to follow the ladder).

Do rivers have a smell? Animals have a keen sense of smell and the volume of rivers is enormous. Seems like a random-walk sniffing for rivers would be effective.

I thought that project already had salmon spillway weirs.

Fish ladders and spillway weirs are fish killers that impose a decimation on the salmon population at each elevation change. Dams destroy the estuary and natural wetland environments that salmon need to reproduce. Dams reduce water flow and silt over gravel beds. Dam impoundments cause stream and river temperatures to rise, suffocating fish. Dam removal is not just obstacle removal, it is habitat restoration and rehabilitation.

I feel like that's just a block of true-ish text but doesn't address the actual comment.

Nothing you said talked about salmon spillway weirs.


Yeah the dams also tend to regulate flows in the river system which doesn't allow natural cycles of peaks and valleys to help regulate parasites.

This isn’t exactly true. Fish ladders and weirs shouldn’t be grouped together like this. Many hatcheries have a weir salmon cannot cross and a ladder as the alternative path the fish take by feeling the flow of water across the ladder and going upstream. The ladders lead to hatcheries where the fish reproduce. And new tiny fish are efficiently raised in protected tanks and later released to go back downstream. In other words, the weir and ladder are a combination to make the hatchery work, and not substitutes for each other. Also ladders can work very well. There are many badly designed ones but the good ones basically let every fish move upstream.

Much of what you said is an exaggeration, for where a habitat disappears with a dam, different habitats appear.

But regardless, the point is that salmon were still breeding there. The "return" is an unwarranted claim, for they never stopped coming and spawning.


Salmon were not still breeding there, this is the first return in over 100 years.

October of this year:

> a fall-run Chinook salmon was identified by ODFW’s fish biologists in a tributary to the Klamath River above the former J.C. Boyle Dam, becoming the first anadromous fish to return to the Klamath Basin in Oregon since 1912 when the first of four hydroelectric dams was constructed, blocking migration.

https://www.dfw.state.or.us/news/2024/10_Oct/101724.asp


>salmon were still breeding there. The "return" is an unwarranted claim, for they never stopped coming and spawning.

let's read

"Less than a month after four towering dams on the Klamath River were demolished, hundreds of salmon made it into waters they have been cut off from for decades"

what does that mean

"salmon are once more returning to spawn in cool creeks that have been cut off to them for generations."

"salmon, which were cut off from their historic habitat"

"salmon that have quickly made it into previously inaccessible tributaries"


so...you're saying that the salmon are able to access places they haven't been able to access? that's like you're trying to tell us that the damn dam was what was preventing it. it's like the dam being removed was the reason for these salmon to gain access to the spots. i'm still confused. /s

Different habitats of algae and mud, so I'll agree of course better than nothing while also very far from the previous quality.

Not dams impose climate change that destroys all things.

They don't work all that well compared to an open river.

This article is better at explaining environmental issues the dam caused

https://www.bbc.com/future/article/20240903-removing-the-kla...


How do they know? I thought salmon always return to the same river, so a river no salmon come from won't get any returning, but I guess a certain percent are adventurous?

If all salmon returned to the same river then there would be only one river with Salmon spawning. Maybe they do have perfect memory, but a certain percentage of them get carried to other rivers by birds of prey who want to have Salmon in THEIR river

Actually- its birds like ducks eating the eggs and a percentage of eggs surviving the ingestion and being shit out into a new river

The elegant beauty of Nature.

The river wasn't entirely inaccessible to salmon, the dams just prevented access to the upper lakes and river segments.

Most salmon do, but a small percentage always stray. If you think about it, it is kinda an obviously necessary behavior given that many current salmon habitats were not present during the last ice age.



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