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>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

>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

kranner 2y ago
There could be an environmental feature they prefer in that spot. Edit: the article mentions lower concentration of harmful algae and a cooler temperature.
- joseda-hg 2y ago
  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
  - chmod775 2y ago
    Nice water flows downstream, terminates in the ocean. They simply follow it back upstream.
    - jagged-chisel 2y ago
      I’m with you on this. Found some tasty water? Swim towards it. It gets tastier the further we go? Keep going.
      - monknomo 2y ago
        Yeah, no need to make this complicated.
      - rightbyte 2y ago
        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.
        bad_haircut72 2y ago
        Word gets around? Animals probably have way better communication than we think. One crab says to a friendly eel "hey dont tell those damn Salmon but this estuary is good again" and before you know it, everyone's favourite restaurant is booked out till March.
        cruffle_duffle 2y ago
        I used to go to this estuary until it became too crowded.
        jaggederest 2y ago
        It's all chemoception, the same as with single cell organisms. They swim towards a saline gradient ( which they can taste, for sure ) and follow it up into fresher and fresher water.
    - Angostura 2y ago
      Thanks, I was bang my head on this one, until you suggested a nice simple solution
astura 2y ago
> 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.html https://www.livescience.com/9760-study-reveals-infants-walk....
- netcraft 2y ago
  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?
  - deleted 2y ago
    [deleted]
  - gherkinnn 2y ago
    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.
  - gambiting 2y ago
    >>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.
    - netcraft 2y ago
      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?
conradev 2y ago
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.
- shkkmo 2y ago
  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.
  - idunnoman1222 2y ago
    None of those salmon were born there because the Damn was in the way
    - deleted 2y ago
      [deleted]
    - jimnotgym 2y ago
      They were born in the lower part of the river, below the dam. They just followed it up a bit!
    - shkkmo 2y ago
      Water flows downstream. The water the Salmon were born is smells substantially the same as the water that is from up river, that chemical content will change as tributaries enter the river but you'll probably see greater variations between forks than between spots of the same river.
- Aurornis 2y ago
  > 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)
shkkmo 2y ago
> 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.
- jimnotgym 2y ago
  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.
- Suppafly 2y ago
  >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.
tokai 2y ago
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 https://www.science.org/doi/full/10.1126/sciadv.aav1112
- tsimionescu 2y ago
  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.
  - idunnoman1222 2y ago
    Clearly, the story that salmon go back to spawn and their birth pool is not 100% true
  - RaftPeople 2y ago
    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?
  - inciampati 2y ago
    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.
jncfhnb 2y ago
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.
- DFHippie 2y ago
  > 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.
  - Retric 2y ago
    Practice itself is an instinctual behavior. Evolution isn’t limited to direct methods, as long as it works that’s enough.
  - jncfhnb 2y ago
    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.
  - mekoka 2y ago
    Are you saying that a human left to their own devices would not eventually walk? That walking erect is mimicry?
    - jncfhnb 2y ago
      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.
MrMcCall 2y ago
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.
- abid786 2y ago
  This is a bunch of pseudoscience that isn't proven by anything at all and isn't peer reviewed either
  - MrMcCall 2y ago
    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?
    - calfuris 2y ago
      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 ... ?
      - MrMcCall 2y ago
        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.
Aurornis 2y ago
> 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.
snowwrestler 2y ago
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.
- lawlessone 2y ago
  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.
BurningFrog 2y ago
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.
- EasyMark 2y ago
  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
  - BurningFrog 2y ago
    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.
  - piuantiderp 2y ago
    Might just be some kind of salinity thing. Upstream -> Less minerals dissolved
locallost 2y ago
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.
ssnistfajen 2y ago
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.
joe_the_user 2y ago
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.
- cutemonster 2y ago
  Another comment says that some salmons (a small fraction) swim up the randomly "wrong" rivers, instead of back to where they were born. So, a bunch of salmons have been trying each year in the river with that dam? But: "hundreds of salmons failed to swim past a dam" didn't break the news
  - jimnotgym 2y ago
    No. Thousands have been entering and spawning all these years but below the dams. Now the dams are gone some are spawning higher up the river. Not really suprising that they spread out a bit into new habitat, is it?
    - cutemonster 2y ago
      But that's what I wrote? > > swim up the randomly "wrong" rivers And the reason for that is discovering new habitats. But the other comment I referred to, mentions this already so I left that out. Didn't know about this though: > spawning all these years but below the dams. I thought, however, that it'd been funny if such a non-event (the fish didn't ...) had been in the news.
baxtr 2y ago
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.
- mulmen 2y ago
  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.
  - baxtr 2y ago
    Right. But their genes do. You assume: hit the dam > died.
    - mulmen 2y ago
      Yeah pretty much. That’s why the dams were breached.
      - baxtr 2y ago
        And why there still left then?
      - jimnotgym 2y ago
        No it isn't. The remaining salmon population spawned below the first dam because their habitat was cut off. This reduced spawning and juvenile habitat meant less salmon. Now they have the whole river they are spreading out and the numbers can increase again
hinkley 2y ago
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-conservation/noaa-fisheries-restoration-klamath-basin https://www.fisheries.noaa.gov/west-coast/habitat-conservati... Whites Gulch Dam, ca 2008: https://www.fisheries.noaa.gov/feature-story/building-network-restored-habitat-klamath-river-watershed https://www.fisheries.noaa.gov/feature-story/building-networ...
senord 2y ago
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
_yb2s 2y ago
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.
- soulofmischief 2y ago
  Salmon have also displayed possible geomagnetic navigation capabilities, similarly to homing pigeons. https://royalsocietypublishing.org/doi/10.1098/rsbl.2017.0752 https://royalsocietypublishing.org/doi/10.1098/rsbl.2017.075...
  - tyre 2y ago
    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
    - PittleyDunkin 2y ago
      Humans may be capable of geomagnetic sensing as well. As a human myself, I've got to imagine this is extremely difficult to control for sensing vs other forms of navigation (sun, stars, moon, wind, animal migration, etc.)
      - soulofmischief 2y ago
withinrafael 2y ago
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 https://www.youtube.com/watch?v=DggHeuhpFvg
thaumasiotes 2y ago
> 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.
tejtm 2y ago
magnets... but I am not even kidding. they include a tiny bit of magnetic material in their ear. but it must be a genetic construct that informs them what to do with north, they use it to move to particular undersea canyons out in the ocean they have never been to.
nf3 2y ago
It is a mystery, like lots of other phenomena that science fails to explain. Personally I think all those creatures are much more intelligent and aware than we give them credit for. Viewing these creatures as simple automatons is as silly as viewing humans as such.

kranner 2y ago

There could be an environmental feature they prefer in that spot. Edit: the article mentions lower concentration of harmful algae and a cooler temperature.

joseda-hg 2y ago
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
- chmod775 2y ago
  Nice water flows downstream, terminates in the ocean. They simply follow it back upstream.
  - jagged-chisel 2y ago
    I’m with you on this. Found some tasty water? Swim towards it. It gets tastier the further we go? Keep going.
    - monknomo 2y ago
      Yeah, no need to make this complicated.
    - rightbyte 2y ago
      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.
      - bad_haircut72 2y ago
        Word gets around? Animals probably have way better communication than we think. One crab says to a friendly eel "hey dont tell those damn Salmon but this estuary is good again" and before you know it, everyone's favourite restaurant is booked out till March.
        cruffle_duffle 2y ago
        I used to go to this estuary until it became too crowded.
      - jaggederest 2y ago
        It's all chemoception, the same as with single cell organisms. They swim towards a saline gradient ( which they can taste, for sure ) and follow it up into fresher and fresher water.
  - Angostura 2y ago
    Thanks, I was bang my head on this one, until you suggested a nice simple solution

astura 2y ago

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

netcraft 2y ago
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?
- deleted 2y ago
  [deleted]
- gherkinnn 2y ago
  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.
- gambiting 2y ago
  >>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.
  - netcraft 2y ago
    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?

conradev 2y ago

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.

shkkmo 2y ago
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.
- idunnoman1222 2y ago
  None of those salmon were born there because the Damn was in the way
  - deleted 2y ago
    [deleted]
  - jimnotgym 2y ago
    They were born in the lower part of the river, below the dam. They just followed it up a bit!
  - shkkmo 2y ago
    Water flows downstream. The water the Salmon were born is smells substantially the same as the water that is from up river, that chemical content will change as tributaries enter the river but you'll probably see greater variations between forks than between spots of the same river.
Aurornis 2y ago
> 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)

shkkmo 2y ago

> 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.

jimnotgym 2y ago
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.
Suppafly 2y ago
>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.

tokai 2y ago

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

tsimionescu 2y ago
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.
- idunnoman1222 2y ago
  Clearly, the story that salmon go back to spawn and their birth pool is not 100% true
- RaftPeople 2y ago
  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?
- inciampati 2y ago
  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.

jncfhnb 2y ago

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.

DFHippie 2y ago
> 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.
- Retric 2y ago
  Practice itself is an instinctual behavior. Evolution isn’t limited to direct methods, as long as it works that’s enough.
- jncfhnb 2y ago
  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.
- mekoka 2y ago
  Are you saying that a human left to their own devices would not eventually walk? That walking erect is mimicry?
  - jncfhnb 2y ago
    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.

MrMcCall 2y ago

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.

abid786 2y ago
This is a bunch of pseudoscience that isn't proven by anything at all and isn't peer reviewed either
- MrMcCall 2y ago
  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?
  - calfuris 2y ago
    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 ... ?
    - MrMcCall 2y ago
      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.

Aurornis 2y ago

> 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.

snowwrestler 2y ago

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.

lawlessone 2y ago
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.

BurningFrog 2y ago

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.

EasyMark 2y ago
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
- BurningFrog 2y ago
  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.
- piuantiderp 2y ago
  Might just be some kind of salinity thing. Upstream -> Less minerals dissolved

locallost 2y ago

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.

ssnistfajen 2y ago

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.

joe_the_user 2y ago

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.

cutemonster 2y ago
Another comment says that some salmons (a small fraction) swim up the randomly "wrong" rivers, instead of back to where they were born. So, a bunch of salmons have been trying each year in the river with that dam? But: "hundreds of salmons failed to swim past a dam" didn't break the news
- jimnotgym 2y ago
  No. Thousands have been entering and spawning all these years but below the dams. Now the dams are gone some are spawning higher up the river. Not really suprising that they spread out a bit into new habitat, is it?
  - cutemonster 2y ago
    But that's what I wrote? > > swim up the randomly "wrong" rivers And the reason for that is discovering new habitats. But the other comment I referred to, mentions this already so I left that out. Didn't know about this though: > spawning all these years but below the dams. I thought, however, that it'd been funny if such a non-event (the fish didn't ...) had been in the news.

baxtr 2y ago

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.

mulmen 2y ago
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.
- baxtr 2y ago
  Right. But their genes do. You assume: hit the dam > died.
  - mulmen 2y ago
    Yeah pretty much. That’s why the dams were breached.
    - baxtr 2y ago
      And why there still left then?
    - jimnotgym 2y ago
      No it isn't. The remaining salmon population spawned below the first dam because their habitat was cut off. This reduced spawning and juvenile habitat meant less salmon. Now they have the whole river they are spreading out and the numbers can increase again

hinkley 2y ago

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-conservation/noaa-fisheries-restoration-klamath-basin https://www.fisheries.noaa.gov/west-coast/habitat-conservati... Whites Gulch Dam, ca 2008: https://www.fisheries.noaa.gov/feature-story/building-network-restored-habitat-klamath-river-watershed https://www.fisheries.noaa.gov/feature-story/building-networ...

senord 2y ago

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

_yb2s 2y ago

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.

soulofmischief 2y ago
Salmon have also displayed possible geomagnetic navigation capabilities, similarly to homing pigeons. https://royalsocietypublishing.org/doi/10.1098/rsbl.2017.0752 https://royalsocietypublishing.org/doi/10.1098/rsbl.2017.075...
- tyre 2y ago
  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
  - PittleyDunkin 2y ago
    Humans may be capable of geomagnetic sensing as well. As a human myself, I've got to imagine this is extremely difficult to control for sensing vs other forms of navigation (sun, stars, moon, wind, animal migration, etc.)
    - soulofmischief 2y ago

withinrafael 2y ago

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

thaumasiotes 2y ago

> 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.

tejtm 2y ago

magnets... but I am not even kidding. they include a tiny bit of magnetic material in their ear. but it must be a genetic construct that informs them what to do with north, they use it to move to particular undersea canyons out in the ocean they have never been to.

nf3 2y ago

It is a mystery, like lots of other phenomena that science fails to explain. Personally I think all those creatures are much more intelligent and aware than we give them credit for. Viewing these creatures as simple automatons is as silly as viewing humans as such.