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[Matt]

I love a challenge.  Consider the gauntlet picked up.

P.S. You said peer reviewed...you did not say the peers had to agree.

as in peer-reviewed journal, such as Fisheries Ecology and Management.

So does the "natural selection process" only apply to the hatchery fish when first cultivated and then no longer apply when that fish mates and the cycle repeats (naturally) over the years. Would the new "diversity" not add to the local gene pool and if unfit be removed and back the way it was?

Would the hatchery program on the great lakes not be a "benefit" to the gene pool as they have now diversified to freshwater as opposed to just salt?

Also, the vedder which has incredible amounts of fish is doing quite well clearly due to the hatchery. Now, would these fish all become dumb and die off with out the hatchery... unlikely I would think. I'm sure the offspring will figure it out and do fine.

Fish stocks are declining and if it was not for hatchery's I'm sure we would be in trouble.... In the states it has brought back nearly wiped out runs....

Altering the gene pool will very well have an effect, but negative... could also be positive I would think.

While the influx of new genes may, in some cases, benefit a gene pool, the removal of mate-selection is detrimental to its health, no question about it.

My understanding of hatcheries in the states is that they pump out huge numbers of fish.  Would that avoid collapse if the hatchery was removed?  I'm not sure, but I have my doubts.  In that case, I wouldn't say that that's "bringing back" a run of fish.  That's conjecture of course, so not eating any salmon hearts if I'm wrong on that one, but I wouldn't mind being proven wrong if anyone can find evidence to the contrary.  It would be brilliant if salmonid runs could be restored with hatchery programmes alone, as it would be a faster solution than habitat restoration.

The Vedder has a tonne of coho, yes, are the genetics good?  The reason Vedder coho return in numbers that dwarf any other lower mainland system is because of the huge number of juveniles released into the system.  Even if the odds for those hatchery juveniles are lower than wild fish, some are bound to return by chance.  I've been fortunate enough to have had the opportunity to fish coho in truly wild rivers and Vedder coho don't compare in average size and degree of sexual dimorphism (ie: kype development in males) displayed.  Vedder coho are certainly abundant, but are they as healthy as, say, a truly wild Kimsquit River coho?  I doubt it.

[Matt]

double post.

[silver ghost]

Thanks for the educated replies.

Seems like a damned if you do and damned if you don't situtation.

What if they released the hatchery fish at younger age?


http://abcnews.go.com/Technology/story?id=99347&page=1

http://www.sciencedaily.com/releases/2009/06/090610091224.htm


great articles, thanks for sharing.
BN

[Sandman]

So does the "natural selection process" only apply to the hatchery fish when first cultivated and then no longer apply when that fish mates and the cycle repeats (naturally) over the years. Would the new "diversity" not add to the local gene pool and if unfit be removed and back the way it was?

Would the hatchery program on the great lakes not be a "benefit" to the gene pool as they have now diversified to freshwater as opposed to just salt?

Also, the vedder which has incredible amounts of fish is doing quite well clearly due to the hatchery. Now, would these fish all become dumb and die off with out the hatchery... unlikely I would think. I'm sure the offspring will figure it out and do fine.

Fish stocks are declining and if it was not for hatchery's I'm sure we would be in trouble.... In the states it has brought back nearly wiped out runs....

Altering the gene pool will very well have an effect, but negative... could also be positive I would think.

I am not so sure the Great Lakes can be used as an example of "improving a gene pool" as there were no Pacific Salmon in the Great Lakes before the hatcheries so there was no gene pool to diversify.  The argument mentioned above is that when the gene pool of a system is near collapse (less than 10 fish let's say) then the introduction of a few hundred hatchery fish, while genetically inferior perhaps, still adds diversity to the pool where the fish pairing up are pairing with a limited number of possible mates (5-10).  This is only true if the brood stock the hatchery fish came from was different (came from a different system) than the stock from which the 10 wild fish came. Usually, the hatchery tries to keep brood stock local, taking brood from the local pool, as this increases the compatibility of the offspring to the conditions of the system.  If the hatchery fish came from the same stock as the 10 wild fish, then there is probably not much added diversity as there would probably be more diversity between the 10 wild fish than between the hundreds of hatchery introduced fish.

[doja]

I am not so sure the Great Lakes can be used as an example of "improving a gene pool" as there were no Pacific Salmon in the Great Lakes before the hatcheries so there was no gene pool to diversify.  The argument mentioned above is that when the gene pool of a system is near collapse (less than 10 fish let's say) then the introduction of a few hundred hatchery fish, while genetically inferior perhaps, still adds diversity to the pool where the fish pairing up are pairing with a limited number of possible mates (5-10).  This is only true if the brood stock the hatchery fish came from was different (came from a different system) than the stock from which the 10 wild fish came. Usually, the hatchery tries to keep brood stock local, taking brood from the local pool, as this increases the compatibility of the offspring to the conditions of the system.  If the hatchery fish came from the same stock as the 10 wild fish, then there is probably not much added diversity as there would probably be more diversity between the 10 wild fish than between the hundreds of hatchery introduced fish.

Let me understand this... Before the great lakes had no spwaning salmon, now they do.... sounds like an improvement to me as they have just moved from oceans to freshwater which shows their ability to adapt and "improve" from a hatchery start of life. Albeit in a whole and not directly related to existing rivers with hatchery's.

From my understanding the gene pool is created from exposer to the environment and each individual fish will have a slightly different exposer to different things which gives each one it's own new makeup. The more fish that have different exposer should add to the pool.

Yes the coho in the vedder aren't the best and biggest, however being all the snaggers and such out there it could be considered a not so good quality and was removed via "natural selection"... I'm just throwing that one out

As far as the Kimsquit River coho... Stick the river near a major city like Vancouver and see how fast those "Superior quality's" get removed and put on a BBQ . They are probably more lucky they haven't had major pressure to reduce the gene pool to low numbers or change it to adapt to the new environment.

The problem most salmon face is over fishing which reduces the gene pool. As some of the rivers that have been over fished have now made better comebacks I would assume due to the hatchery adding more fish to become experienced.

Quality's we might like in a salmon may not be good for the pool... A runty, ugly coho may not be kept over a nice big one and even though the bigger and better might appear better in makeup could also be quite detrimental to the species in a urban environment.

These are however just my thoughts...

[Matt]

Doja, you're arguing that a a hatchery is required on the Vedder due to the quantity harvested.  No one would argue that wild production could sustain that harvest.  A river can only support so many fish.

You're correct in the overall idea that exposure to the environment leads to changes in the genepool, but the mechanism you propose isn't the way it happens.  Salmonids produce many offspring, the offspring produced will all have slightly different genetic makeup.  Some genetic make ups will survive better than others. For instance, a particularly wary salmon will likely evade predators, and a salmon with lighter colouration (lets make him white) than normal may be easier to spot for predators.  In this example, the wary salmon has a better chance of surviving to adulthood and spawning than the easy-to-see white salmon.  The wary salmon's offspring receive their parent's wariness.  The white salmon got eaten by a seal, and he didn't get a chance to pass on the unfortunate white gene to any offspring.

Similarly, in the wild, a salmon must find a mate.  Females must compete for the best spot to make a redd, and males must compete with other males for the best females occupying the best redds.  What happens next is similar to what happens in all animals... the most successful females get paired with the most successful males and they spawn on the most desirable redds.  Their offspring will have several advantages (ie: the best genes from their parents, and the best redds to hatch in), and have a better chance of spawning compared to their cohorts.

The hatchery process is less selective- a random male spawner is milked and his milt is mixed with a random female's eggs and they all rear in the same environment.

I don't mean to rag on hatcheries, they certainly are needed on rivers such as the Vedder to sustain a huge harvest or rivers where natural spawning habitat has been ruined (ie: putting a dam below spawning grounds), just the offspring from a hatchery will not be as genetically fit as their wild cousins.

[Sandman]

Let me understand this... Before the great lakes had no spwaning salmon, now they do.... sounds like an improvement to me as they have just moved from oceans to freshwater which shows their ability to adapt and "improve" from a hatchery start of life. Albeit in a whole and not directly related to existing rivers with hatchery's.

I never said that the fact that you can now catch Coho and Chinook in the Great Lakes was not an improvement.  I am sure there are fisherman that fish the Great Lake that would say it is an improvement.  I am saying that the introduction of hatchery fish into the Great Lakes was not an improvement to the gene pool (the original topic of the discussion) as there was no gene pool of Pacific Salmon in the the Great Lakes to improve. 

I am also not convinced that the fact that these Pacific Salmon can live in the freshwater of the Great Lakes is an "improvement" in their genes over their Pacific cousins or that it shows "their ability to adapt and 'improve' from a hatchery start of life", as all salmon can live in freshwater (they are hatched and reared there).  The chinook and coho in the Great Lakes just do not need to adapt to the salt water of the oceans like their Pacific cousins do in their smolt stage, they simply move from the river to the lake without adapting.  I am not so sure this is an "improvement," but it is damn good for the salmon guides in lake Eerie.

[JPW]

Really good information in this thread.  I worked in a hatchery when I was younger and really didn't understand the possible ramifications of what we were doing.  In my eyes, more fish in the river was a good thing, but clearly that is not always the case.   Unfortunately, for those that like to retain the fish they catch, it seems like the best answer in most cases is to protect the remaining wild stock through catch & release and then work on improving the habitat.  Sadly, that type of big picture thinking rarely catches on.  

[Banny]

I do not want to wade into this topic too deeply but I though of this article when I read this thread.  It does a good job of highlighting just one of the evolutionary consequences of raising salmon under hatchery conditions.  Published in Science in 2003.  I have the full PDF if anyone would like to read it (e-mail jordanabannerman @ gmail . com).

Rapid Evolution of Egg Size in Captive Salmon

Daniel D. Heath, John W. Heath, Colleen A. Bryden, Rachel M. Johnson and Charles W. Fox

Captive breeding and release programs, widely used to supplement populations of declining species, minimize juvenile mortality to achieve rapid population growth. However, raising animals in benign environments may promote traits that are adaptive in captivity but maladaptive in nature. In chinook salmon, hatchery rearing relaxes natural selection favoring large eggs, allowing fecundity selection to drive exceptionally rapid evolution of small eggs. Trends toward small eggs are also evident in natural populations heavily supplemented by hatcheries, but not in minimally supplemented populations. Unintentional selection in captivity can lead to rapid changes in critical life-history traits that may reduce the success of supplementation or reintroduction programs.


Cheers,

Jordan

[buck]

There has been so much negative banter about the " Gene Pool " and how it is going to be the demise of our wild stocks. I would suggest that everyone take a hard look at the decline of all of  our wild stocks and decide if we should cease production of hatchery fish. The Thompson River is a perfect example of a system in rapid decline and the answer is to close it until it rebuilds. Good luck. In a number of systems that have had hatchery production of Steelhead  curtailed there are now very few fish. Our interior trout fishery has improved over the years due to hatchery production. Do you really want to   
jeopardize that fishery by closing hatcheries? 

We all would like to go back to the good old days when wild production could sustain our fisheries, but those days are long gone. Funding is not available for any large habitat projects and probably won't be in the future. DFO has just taken a 58 million dollar cut and you will most likely see a decline of hatchery produced fish in the future.

[Sandman]

There has been so much negative banter about the " Gene Pool " and how it is going to be the demise of our wild stocks. I would suggest that everyone take a hard look at the decline of all of  our wild stocks and decide if we should cease production of hatchery fish. The Thompson River is a perfect example of a system in rapid decline and the answer is to close it until it rebuilds. Good luck. In a number of systems that have had hatchery production of Steelhead  curtailed there are now very few fish. Our interior trout fishery has improved over the years due to hatchery production. Do you really want to   
jeopardize that fishery by closing hatcheries? 

We all would like to go back to the good old days when wild production could sustain our fisheries, but those days are long gone. Funding is not available for any large habitat projects and probably won't be in the future. DFO has just taken a 58 million dollar cut and you will most likely see a decline of hatchery produced fish in the future.

No one would deny that "fisheries" benefit from hatcheries.  That is their purpose...to provide a catch and kill fishery.  Closing hatcheries is no guarantee that wild stocks will be able to rebuild in the absence of the added competition with the hatchery stock.  This must also come with habitat restoration, enhancements as well.  Closing the hatchery is not the solution if that is all that is done, since the wild stocks will only continue to decline.  If a hatchery program was deemed necessary in the first place, wild stocks must have been in decline to begin with, and unless the original causes of that decline are reversed (the original cause of the decline was obviously not the hatchery), then removal of the hatchery will do nothing to halt the decline.

[skaha]

--Interior hatchery stock is primarily for lakes that did not have natural populations. The lakes were highly productive and the introduced fish having little competition thrived in many of them.
--The move is toward triploids, as they cannot reproduce they do not loose energy for spawn and if not caught and kept can grow for several years.

--Much of the USA hatchery fish, especially on the Columbia are a result of court actions and promises made by the power and water authorities to replace fish stocks lost due to loss of rearing and spawning habitat due to the many Columbia system dams.

--Every one here is presenting excellent points on pro and con. The pro and con change with each system or situation that you want to use hatchery stock in, thus it is difficult to argue.

--The hatchery stock program can be modified for the intended purpose and in many cases will not be helpful for recovery.
--Kokanee lakes in USA where they want large volumes of fish for catch and keep will be much different than a hatchery intended to reintroduce steelhead to a small stream that does not now have a viable sustainable natural population.
--We interfere at every stage in the cycle... we can see what is going on in a hatchery.. it is more difficult to see what is going on in the open ocean or even get accurate by-catch information...
--Every by-catch steelhead is a reduction in the natural selection... it is just more obvious when we-select the brood stock
--In some instances milt from more than one male are mixed with eggs from the same female, this happens in nature as well as the paired male chases off a potential suitor another male will sneak in for a bit of mischief.
--There are  technical fixes to mitigate hatchery issues raised.. I doubt all are fool proof thus we have to used caution, however I would not want to rule out hatchery assistance in a recovery program as one of the potential tools.