There is similar work going on to restore fish passage underneath I-90 near Issaquah, Washington. Although in that case, the part of the streams that's currently inaccessible is less than a mile for most of them, and 2 miles for one of them. It's a major undertaking to restore a stream bed or channel underneath the interstate.
This will benefit Kokanee Salmon, a kind of salmon that spends all its life in fresh water and does not migrate to salt water like most salmon.
In Lewis Creek, they currently have access to only 1/2 mile of the creek, but in 2021 there were about 1000 of them returning (from Lake Sammamish) to spawn.
There are traditional methods like electrofishing and tagging. But there are also non-invasive methods such as environmental DNA where you can detect organism prevalence from DNA shed into the ecosystem. Our platform was built specifically to help share that type of science for restoration and remediation projects: https://www.ednaexplorer.org
There's an organization of volunteers who walk the streambed during spawning season and mark nests with colored tape on nearby branches. I assume while they're doing that, they also count the fish somehow? They also put a trap near the end of the stream at certain times of the year and count the fish in the trap - the fish are obviously released from the trap afterwards.
Excellent work as expected from NOAA's Habit Conservation team. These fish ladders are such an excellent investment in the future of our inshore fisheries, I wish it were easier to express that to citizens and corporations,
Silly question but if I remember correctly salmon go back to reproduce where they spawned. This suggests that once access is cut up a river, that location loses its salmon (can’t get there, so they don’t reproduce?)
Do they artificially reintroduce the salmon once access is restored or does that “neighbourhood” of salmon somehow survives and keeps trying every year ?
IANAS but my understanding is they keep going upstream - while there's current to push against them - as an instinctual response. I believe water temperature also plays a role.
Salmon hatcheries also artificially boost the quantity of salmon in the stream.
If a salmon hatchery released salmon at the base of a dam, when the fish return and the dam was now gone, they'd just keep going.
However, there's more to it than this, because dammed rivers lacking salmon hatcheries have seen salmon runs start once the dams are removed.
I don't think the old adage that salmon will only return to their original spawning grounds is the whole story.
> I don't think the old adage that salmon will only return to their original spawning grounds is the whole story.
Some percentage will just enter a different stream. Straying could be a genetic strategy, imperfect behavior, accidental, or some mix. And they're not all necessarily distinct; e.g. the genetic strategy might simply work by reducing accuracy in locating the original spawning ground.
Consider that even before humans streams and rivers would naturally be dammed, diverted, or otherwise change in a way that made it more difficult or impossible to reach the original spawning ground. What would be interesting is if the ratio of various phenotypes, like those that effect straying, has changed in response to the ecological upset caused by humans.
Some small percentage of fish go to different streams rather than returning to their “home” stream. There’s also hatcheries that release fish raised elsewhere to try and restore runs without enough fish to sustain a healthy population.
Source: I used to volunteer at one of those hatcheries raising endangered coho and releasing them in the spring. I spent a lot of time chilling in the bushes with NOAA scientists talking about fish.
I'm not an expert, but what I understand is Salmon return to the stream, not the place. They know the stream by smell (that is the minerals and other impurities in the water). They are navigating to what smells like home, every time a new stream enters the one they are in they decide which branch to take. This tends to take them to where they spawned, but there are a lot of errors in each choice.
salmon mostly prefer to return to there natal habitat, but there are a significant number of fish that are wanderers and colinists, so there are now salmon runs happening in far northern watersheds that have only recently become warm enough for
juvinile fish.
also, fish from clutches of eggs that are transplanted to streams with no fish, become native, which points to the homing instinct bieng re attached with each generation rather than hard coded geneticly, though that may happen in some sub species
My lab does fish population monitoring around the Bay, including the mouth of Alameda creek, so I suppose one entry in the "good problems to have" is another potential spot where we could start catching steelhead and chinook, given that we have an extremely limited allowance.
Such good news - for those looking for a relaxing hobby fly fishing is an excellent sport to get into. You spend all day standing in a river trying to out smart some fish and trout are exceptionally beautiful creatures up close.
Agree. I think most fish are beautiful in a way, even the "ugly ones".
What I really love about the fish under discussion here is, for a long time they had no clue why some rainbow trout became steelhead, and some didn't. (They still don't know 100%) Such an interesting story, and a regular rainbow and a steelhead just seem almost like another species - different size, behavior and even taste when you eat them.
You want to have fun, get two fresh water fish biologists in a room and ask them if steelhead and rainbow trout are different species. Everyone has a different opinion they believe in passionately.
People for a long time didn't know what the reproductive cycle of eels is like, because they travel all the way from the Atlantic ocean and back while maturing, so nobody had ever seen a juvenile. Too bad they're critically endangered.
In a discussion about increasing fish population "after decades of effort", it's surreal to see a suggestion to kill them, or at the very least rip a hole in their mouths.
I'm always surprised at how people can be so unaware, suggesting killing as a meditative and beautiful activity...
I'll contrast with sibling comments. You're correct to raise caution towards fishing Pacific salmon, even in catch and release. Release mortality from one study I've found is about 25-40% https://www.sciencedirect.com/science/article/pii/S016578362... It's worse during high water temperatures. They're likely quite fatigued by the time they arrive.
That said, this caution is not always warranted generally. Location, species, and season significantly matter. In healthy ecosystems, there's no harm to the group even if the individual fish might not agree.
my claim would be something like how the recommendation of fishing in response to news of conservation efforts is as absurd as recommending spankings in response to news of more babies being born: stupid, harmful, and self-serving.
I’m sure we both have cared for and loved animals at some point! There’s nothing wrong with recognizing that a fish can feel pain much like a cat or a dog or a rabbit or a horse.
Can an insect feel pain? What about a mushroom, or a plant? What things are conscious enough to feel pain? I'm genuinely asking because I because it seems arbitrary as to where the line gets drawn. Before the 1980s it was the medical consensus that babies weren't capable of feeling pain even though this is now widely recognized as untrue.
There are a lot of different fish, and most are not threatened in anyway. Often the larger threat is over population and they need predators - like humans - to prevent that.
I mean catch and release is better than being dinner, and the prevalence of fly fishing as a hobby goes a long way toward garnering public and financial support for restoration activities.
People treat you differently if they think you have money or did something heroic. Sometimes people don't want to be treated any differently just because you have or did something special. If you liked who I was before you knew I had money, then I'll know you liked me for me, and not my money. The Bay Area foundation might be someone who made it rich in an IPO but doesn't want their friends to know about it.
This will benefit Kokanee Salmon, a kind of salmon that spends all its life in fresh water and does not migrate to salt water like most salmon.
In Lewis Creek, they currently have access to only 1/2 mile of the creek, but in 2021 there were about 1000 of them returning (from Lake Sammamish) to spawn.
Do they artificially reintroduce the salmon once access is restored or does that “neighbourhood” of salmon somehow survives and keeps trying every year ?
Salmon hatcheries also artificially boost the quantity of salmon in the stream.
If a salmon hatchery released salmon at the base of a dam, when the fish return and the dam was now gone, they'd just keep going.
However, there's more to it than this, because dammed rivers lacking salmon hatcheries have seen salmon runs start once the dams are removed.
I don't think the old adage that salmon will only return to their original spawning grounds is the whole story.
Some percentage will just enter a different stream. Straying could be a genetic strategy, imperfect behavior, accidental, or some mix. And they're not all necessarily distinct; e.g. the genetic strategy might simply work by reducing accuracy in locating the original spawning ground.
Consider that even before humans streams and rivers would naturally be dammed, diverted, or otherwise change in a way that made it more difficult or impossible to reach the original spawning ground. What would be interesting is if the ratio of various phenotypes, like those that effect straying, has changed in response to the ecological upset caused by humans.
Source: I used to volunteer at one of those hatcheries raising endangered coho and releasing them in the spring. I spent a lot of time chilling in the bushes with NOAA scientists talking about fish.
Stocking can give it a faster kickstart though
What I really love about the fish under discussion here is, for a long time they had no clue why some rainbow trout became steelhead, and some didn't. (They still don't know 100%) Such an interesting story, and a regular rainbow and a steelhead just seem almost like another species - different size, behavior and even taste when you eat them.
I'm always surprised at how people can be so unaware, suggesting killing as a meditative and beautiful activity...
That said, this caution is not always warranted generally. Location, species, and season significantly matter. In healthy ecosystems, there's no harm to the group even if the individual fish might not agree.
Also are you aware of the California native tribes who exempt themselves from fishing regulations?
Is your claim that anglers decimate fishing population?
my claim would be something like how the recommendation of fishing in response to news of conservation efforts is as absurd as recommending spankings in response to news of more babies being born: stupid, harmful, and self-serving.
fish swim happily upstream,
while rocks sink down fast.
And nope, no eating meat for me (and like half a billion other people). It’s both easier and more empowering than one might think!
I'd like to live in a world where a company picking up after itself isn't "refreshing"
Why was a 'Bay Area foundation' referenced yet left nameless? I never understand the logic behind this convention..
(/joke)
Sometimes anonymity is a condition of the gift.