Fishing with Rod Discussion Forum
Fishing in British Columbia => Fishing-related Issues & News => Topic started by: ShaunO on February 17, 2016, 08:59:56 AM
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A very interesting article where researchers from Oregon State University and the Oregon Department of Fisheries and Wildlife assert that fish raised in a hatchery environment change on a genetic level from their wild counterparts, in just one generation . I've always been reluctant to believe that a smolt reared in a hatchery could be any different than a smolt raised in an open stream, but it seems I am wrong about that.
http://www.eurekalert.org/pub_releases/2016-02/osu-des021216.php
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Very interesting in terms of implications of potential change to hatchery programs. Here's a link to the paper:
http://www.nature.com/ncomms/2016/160217/ncomms10676/full/ncomms10676.html
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Thanks for posting this. I can't see many changes on the horizon for BC's steelhead hatchery program coming from this study, as efforts are made to stop hatchery fish from spawning together and spawning with wild fish. Of course they do but the only way to stop that would be to curtail the hatchery program altogether. The Canucks have a better chance of winning the cup this year than that happening ;D
Already I'm hearing grumblings from anglers on the C-V, suggesting more hatchery fish should be produced ... I predict it won't be long before hatchery fish are used for brood stock on this system and wild C-V fish are a memory.
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er. The Canucks have a better chance of winning the cup this year than that happening ;D
Oh Ye of little faith.... Chris will welcome you to the dark (blue) side ;D
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Oh Ye of little faith.... Chris will welcome you to the dark (blue) side ;D
No faith is right! I turned 66 on Sunday and am becoming more cynical yearly ;D
I will always be a Canuck fan, no matter how bad they are, and will always advocate for wild steelhead, no matter how dismal their future may be.
We are really looking forward to our annual spring counts; the work Buck and I supervised this past summer at Centennial Channel hopefully will show improved numbers and the trend for spawner numbers at the outlet of Chilliwack Lake will give an indication of this years upper river wild population.
Anyone here have an update on the number of wild fish in holding for the Chilliwack River hatchery program? last I heard it was about 30
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Well Happy Birthday!
(http://i158.photobucket.com/albums/t82/Willy1956/4153383020_201103_omag_aging_600x411_xlarge_zpsqovipyz5.jpeg) (http://s158.photobucket.com/user/Willy1956/media/4153383020_201103_omag_aging_600x411_xlarge_zpsqovipyz5.jpeg.html)
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Thanks Bill ;) Are there 66 candles there?
Back on topic, does anyone know how many fish have been tubed?
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Dave, 31 females, 17 bucks.
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Thanks Pete
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Is there always that much of a gender difference in returns? Sorry for the hijack
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If I recall broodstock anglers always had a hard time capturing enough wild males. Buck might chime in here. The hatchery fish entered in the Wally Hall Memorial derby this year are at an approximate 3:1 ratio favoring females.
There was an interesting post recently showing released steelhead juveniles also had a higher percentage of females.
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In respect to enumerating adult Pacific Salmon species like Sockeye, there can be sex ratio differences annually, between geographic areas and run-timing groups. Some areas can have close to 50:50 while others can be skewed 60:40 (males or females being more prominent) for males or females. It is challenging to obtain a unbiased, representative sample to reflect the true sex ratio. If surveys have poor spatial (space) and temporal (time) representation that could bias the sex ratio. Ideally, ground surveys should be done at equal frequency intervals over time and cover the extent of spawning for a particular stream. Seems like an easy thing to satisfy, but in reality it can be challenging. Fish behaviour, predators and environmental conditions are factors that play into this.
For instance, males typically die sooner than females and leave the system making them less recoverable for survey crews. Secondly, extreme environmental conditions (water temperatures or water levels) can impact sex ratio. For instance, female Sockeye can experience higher enroute mortality if migratory conditions in the Fraser are extreme. Thirdly, predators (specifically bears) on spawning grounds can remove salmon carcasses making them less available for crews to recover in order to determine sex ratio. If salmon abundances on a particular stream are low and there many bears are feeding during the day then it may not leave much for crews to count in order to determine sex ratio - especially if they are only visiting the stream once every 7 days. This may necessitate survey frequency to be even more often.
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efforts are made to stop hatchery fish from spawning together and spawning with wild fish. Of course they do but the only way to stop that would be to curtail the hatchery program altogether.
I understand the Province no longer stocks fertile trout - just sterile fish. If only sterile steelhead smolts were released from hatcheries chances of wild and hatchery breeding interaction would be zero. Of course sterile hatchery steelhead could still compete with wild fish for food and resources.
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I understand the Province no longer stocks fertile trout - just sterile fish. If only sterile steelhead smolts were released from hatcheries chances of wild and hatchery breeding interaction would be zero. Of course sterile hatchery steelhead could still compete with wild fish for food and resources.
Hmmm, not sure about what the FWFSBC stocks in lakes but you raise an interesting and thought provoking point regarding hatchery steelhead releases. This technology of course costs more money but the long term implications, ie curtail the use of wild fish, use excess hatchery fish as brood stock makes a lot of sense, imo. I'm looking for a negative impact .... honestly can't see one just now.
The interaction of wild and hatchery fish on the C-V is pretty much a moot point as hatchery releases are mainly below the Vedder Bridge, an area not particularly well suited to rear wild juveniles, for so many reasons as I'm sure you know.
Good thoughts RalphH. I would like to hear you or others expand on this possibly ground breaking idea.
Edit. Could sterile steelhead still return to their home river? Need some experts to respond ...
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Hmmm, not sure about what the FWFSBC stocks in lakes but you raise an interesting and thought provoking point regarding hatchery steelhead releases. This technology of course costs more money but the long term implications, ie curtail the use of wild fish, use excess hatchery fish as brood stock makes a lot of sense, imo. I'm looking for a negative impact .... honestly can't see one just now.
The interaction of wild and hatchery fish on the C-V is pretty much a moot point as hatchery releases are mainly below the Vedder Bridge, an area not particularly well suited to rear wild juveniles, for so many reasons as I'm sure you know.
Good thoughts RalphH. I would like to hear you or others expand on this possibly ground breaking idea.
Edit. Could sterile steelhead still return to their home river? Need some experts to respond ...
Males potentially would, assuming hey undergo false spawning characteristics as they are not hormonallay sterile, only functionally sterile.
Females however are hormonally and functionally sterile, and do not undergo false spawning. As such I would think they have no incentive to migrate back upriver .
Saw something similar with 3n kokanee. Caught a few (37) Presumably 4 year old males that had all the morphological changes associated with spawning and were in the shallows area of the lake, whilst the only female we got was a dirty chrome and in the deeper portion of our shallow set.
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My question is (and I didn't read all the reports) is if they know how long it takes to undo the changes. If I'm reading it right, it isn't that the genetic code is different, just different items activated. What I would be curious seeing if it a hatchery fish then spawns with a wild fish in the wild, do those activated codes transfer to the offspring or does growing up in the wild undo that? Seems like some of these activations could be because of how the fish grew up and wouldn't necessarily effect offspring long term.
Relating to something more similar, take a child raised in a third world nation, extremely poor, and a child raised wealthy in BC. Very different needs and way to grow up. If both moved to the middle of Alberta and lived similar lives after age 20, they would still be different at 80. However, even without any contact, these two people's kids, both growing up in the same town in the middle of Alberta are going to be much more similar than their parents. If both those live and die in the same town and have kids, that generation is going to be closer to each other than they are to their grandparents.
In other words, perhaps it isn't as big of a deal as the people yelling the sky is falling? It might be but I'm not sure this study shows what it needs to.
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Hopefully someone with a background in salmonid genetics will respond TNAngler. Your analogy appears to makes sense, at least to me.
In a perfect world only wild steelhead would spawn together but we all know those days are long gone on the C-V. Personally, I believe any steelhead spawning and subsequently rearing in the available habitat, smolting, migrating and later returning as adults is a good thing.
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Thanks to the OP for the interesting research finding.
So the finding is that hatchery fish have basically the same genome as wild fish, but the level of gene expression has been altered in hundreds of genes as a result of hatchery rearing, and that diferential gene expression occurs quickly (within one generation) and is passed down as an inheritable trait (epigenetics).
In this case, the investigators show that genes involved in metabolism, wound healing and immune response are up-regulated presumably as a result of the high-density hatchery rearing where injury, attacks from other fish, and infection are far more prevalent than in the wild. It would seem like a pretty nifty adaptation, but there is no such thing as a free lunch, so as a result of those changes, they lose some reproductive fitness in other undetermined ways and ultimately only reproduce at 85% the success rate of wild fish in the wild.
One might be tempted to conclude that these hatchery fish have now become weaker or inferior to wild fish but they cite another study which concludes hatchery fish have almost twice the reproductive success as wild fish when spawned in captivity. So really, these fish have simply responded to new selective pressure placed on them at the time (hatchery rearing) and adapted to the new environment, though the speed at which it occurred is pretty amazing. Of course a hatchery is 'unnatural' compared to a wild stream so if these adaptions ends up reducing fitness in an environment they they need to survive in later, then that's not desirable. If these changes end up being slower to revert than they took to appear and last through multiple generations, then the implications are serious.
My question is (and I didn't read all the reports) is if they know how long it takes to undo the changes. If I'm reading it right, it isn't that the genetic code is different, just different items activated. What I would be curious seeing if it a hatchery fish then spawns with a wild fish in the wild, do those activated codes transfer to the offspring or does growing up in the wild undo that? Seems like some of these activations could be because of how the fish grew up and wouldn't necessarily effect offspring long term.
This is a good question as the authors dont claim that these changes are permanent or will not somehow otherwise change again over time. These fish have incredible adaptability so a return to natural selective pressures may result in hatchery fish eventually regaining 'wild' physiology again, and maybe relatively quickly (pure speculation on my part). However the authors do make his cautionary hypothesis: "As subsequent generations of domestication accrue, we speculate that the regulatory changes to expression become codified with gradual and more targeted shifts in allele frequencies". Hatcheries use wild fish for brood stock (someone correct me if I'm wrong), so I imagine there have been concerns about multi-generation effects of hatchery only lineage for some time.
Relating to something more similar, take a child raised in a third world nation, extremely poor, and a child raised wealthy in BC. Very different needs and way to grow up. If both moved to the middle of Alberta and lived similar lives after age 20, they would still be different at 80. However, even without any contact, these two people's kids, both growing up in the same town in the middle of Alberta are going to be much more similar than their parents. If both those live and die in the same town and have kids, that generation is going to be closer to each other than they are to their grandparents.
Actually this is essentially what they did. To use your analogy, they took salmon steelhead raised in a third world nation (hatchery) and salmon steelhead raised in wealthy BC (wild stream) that both moved to the ocean (rural Alberta) as teens then lived similar lives from that point on. When they returned to spawn, they found that when hatchery fish were bred with other hatchery fish, their progeny's gene expression was notably different than when wild fish were bred with other wild fish, but that differential expression was not present when hatchery fish were bred with wild fish and vice versa. As to what happens when second generation hatchery fish breed with each other and if any of the upregulated genes start to revert to the 'wild' state seems to be anyone's guess at this point.
It's an intriguing finding and hopefully such interesting research will continue and maybe might lead to changes that can be made in hatchery rearing practices to improve survivability and sustainability.
correction: the study used steelhead, not salmon
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A most excellent post DanL and thanks for sharing your obvious expertise! If you have any thoughts or ideas on how BC's steelhead hatchery program could be improved, genetically or otherwise, I'm sure you would have a large audience, me front and center :)
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I understand the Province no longer stocks fertile trout - just sterile fish. If only sterile steelhead smolts were released from hatcheries chances of wild and hatchery breeding interaction would be zero. Of course sterile hatchery steelhead could still compete with wild fish for food and resources.
I suspect the triploid (sterile)steelhead would not return to the river for our enjoyment. But I like the idea if I can catch them.
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Here's two links to another article (this one from UBC) relating to something called 'reverse speciation' examining two types of stikleback in a lake on the island. It speaks to reverse speciation being a relatively rapid process in Canada, due to the relative recency of various species' presence in our freshwater lakes. Again, possible implications for the phenomena we're examining in the first article posted (even though steelhead are anadromous).
http://www.sciencedirect.com/science/article/pii/S0960982216000403
https://www.sciencedaily.com/releases/2016/02/160223074533.htm
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A most excellent post DanL and thanks for sharing your obvious expertise! If you have any thoughts or ideas on how BC's steelhead hatchery program could be improved, genetically or otherwise, I'm sure you would have a large audience, me front and center :)
I wish I did but no, unfortunately I have no particular insights into hatchery rearing practices though I do think we should petition our govt to continue funding basic research like this and to actually listen to what the science tells them.
Truduea's mandate letter to the new Fisheries Minister and Science Minister says a lot of good things prioritizing conservation and evidence based policy setting, but we'll see if that's just talk or what.
I do have a question for the steelhead experts and those experienced in hatchery practices. What proportion of Salmon and Steelehad return to their natal tributaries? ie. For arguments sake lets say every single Vedder fish was released from Slesse creek, how many return to the exact same creek vs how many stray and end up in other Vedder tribs either upstream or downstream?
In light of this research finding, if every single hatchery raised fish returned to the hatchery without exception, then potential cross-breeding with wild stock would not be much of an issue as they would be simply be culled at the hatchery. The more that bypass the hatchery, obviously the greater the risk of breeding with wild stocks.
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I do have a question for the steelhead experts and those experienced in hatchery practices. What proportion of Salmon and Steelehad return to their natal tributaries? ie. For arguments sake lets say every single Vedder fish was released from Slesse creek, how many return to the exact same creek vs how many stray and end up in other Vedder tribs either upstream or downstream?
Ah, the million dollar question ;) and the answer is nobody knows. There is no adult steelhead stock assessment done on this system, other than the minor work Buck and I do on a few known spawning sites (year 6 coming up).
I have observed a small fall white Chinook population in Sweltzer Creek, most likely Chilliwack hatchery strays, and because of the warmer and more productive water these fish may actually be producing a viable spawning population. Again though, as far as I know this possibly of wild recruitment is not being monitored.
The information you request, along with more advanced hatchery techniques like matrix spawning of brood stock, elimination of air spawning, etc, would go a long way to improving what I think could be a much better delivery of the program on this system.