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[redtide]

i remember we used to catch some true cod called "grey cod". some were caught while jigging with buzz bombs quite deep.they had very flakey white meat and were quite good. this was near sechelt about 10 years ago...maybe gooey was talking about these fish. they easily averaged 3-5lbs. havent caught any since though!

[Gooey]

I don't know if anyone here has heard the name Al Lill, he is a family friend, he's the one I referranced.  Currently he has come out of retirement from the DFO I believe and most  recently has been been  the project consultant for the Greater Georgia Basin Steelhead Recovery Action Plan.  He was the one the I spoke to regarding hatchery genes in the gene pool etc.  

I took some genetics coarse (3rd year) and have a biology background too....any how, he an I had a relatively indepth conversation on this topic.  At one point I firmly believe that if you take 2 hatcheries and they spawn naturally, then the offspring are as good as wild ; afterall the offspring had to endure all the pressures of natural selection .  

Thats not the case.   Weak genes from that initial hatchery brood will remian in the population and as Al pointed out to me, within 3-4 generations, those genes can really start to hurt the gene pool.  

Just going back to grade 11 bio and the punnett square, one can see that negative (recessive) genes can hide in the gene pool in a heterozygous allele (search the terms on google if you want to understand a little more).

Bottom line is that there are very few rivers I am aware of that the main goal is to make sure that run doesnt die out.  I think most hatcheries are there with the sport and commericial industry in mind...I will ask Al for his imput on this and let you know.

[Rodney]

Good points Gooey. I read that over three times and tried to pick out a few things, so here they are:

Recessive alleles are not necessarily the negative traits.

What is the difference between mating of two hatchery spawners that both are heterozygous and mating of two wild spawners that also are heterozygous?

Normally natural selection favours strong individuals (ie. bigger fish, more aggressive fish, larger spawners, resistant to disease). I do not totally buy the theory that hatchery stock will extinguish the population because selection favours them yet they are the ones supposedly have the weak alleles. If the third generation of the hatchery or wild strains are homozygous recessive, and let's say the recessive allele disadvantages them, wouldn't that eleminate them in the population? This would then favour those who are homozygous dominant or heterozygous, and the process continues and the % recessive allele will be lowered. What you are saying is, the first generation will be all good as they are either homozygous dominant or heterozygous, but eventually in the third or forth generations, all of a sudden they all become homozygous recessive and that will wipe out the population. What is the chance that the physical trait of the recessive allele becomes dominant in the population when selection favours the dominant allele 3:1?

This doesn't mean I don't believe hatchery has a negative implication on the population. The major negative impact usually lies within the juvenile stage, which a lot of people often neglect. Competition between hatchery and wild juveniles usually favours hatchery fish as they are bigger and stronger. Competiton maybe direct or indirect. Direction competition is caused by competing over space. Indirect competition is caused by the race for the limited amount of food in the wild. First year marine survival rate is dictated by how well the juveniles do in the stream before smoltification. If the ocean condition is not ideal, then usually the hatchery smolts will win.

Saturday afternoon, I am talking about genetics....

[Gooey]

To answer your questions:
No, not all recessive genes are negative but remember that with a hatchery brood stock many more fish make it thru the early phase of life when natural selection would have culd the weak out.  Once they get their foot  hold (make it thru the first year or what ever) then they have a better chance of over coming many of those selective forces and returning to spawn.   Keep in mind too that recessive genes probably have been selected AGAINST in the past and have become recessive to a dominant (more competative) gene that was selected for.

2nd question is a tough one...the main problem in mating 2 hatchery fish is that there is a high likelyhood that there will be a common blood line and hence complications with inbreeding.  as well the hatchery fish were helped thru the first part of life and indeed the may pass on less than desirable genes where as the wild pair should technically be more competitive.

I agree that hatchery stock can't wipe out a run by eventually converting the population to homzygous recessive.  It may make them more suseptible to a catastrophy tho like a disease tho.  I think the main concern is that after a while most of the natural gene pool will be lost and you get a run of runt fish (Capilano is a great example).  There are some nice 8-10 lb fish in the cap...maybe they are the Homozygous Dominant.  Lets assume the cap was fully restored to its former state (particularly spawning ground) I bet if the current gene pool on the cap was used to repopulate it, the run would die out relatively quickly.  Its only because the hatchery pumps out hundreds of thousands of smolts that the get 20-30,000 runts back.

Thanks for the mental work out there.  Dont know if everything I said is bang on...its been ages since I referred back to my genetics that much!

[Rodney]

The first part has a very good point about hatchery raised juvenile would do better in the first portion of the life cycle where natural selection is at work big time, so negative recessive alleles get a free ride into the population.

What about ocean adult and spawner phases though?

Do hatchery raised fish compete just as well as wild strains when obtaining food in the ocean?

Do hatchery fish spawn just as well as wild fish (fecundity, survival rate of eggs, etc)?

Ok two more questions, almost....

1. Why would first generation hatchery fish (produced from two wild fish) be worse than first generation from two wild fish in the wild?

2. What is the chance of two hatchery fish end up mating together in the river?

I'll attempt to answer both (you all can stone me at the river cleanup if I am wrong ):

1. Having two wild parents artificially spawned is not necessarily bad, but not perfect either. The wild parents receive a free ride to the hatchery comfortably. They sit in the hold tank until they reach sexual maturity, then they are artificially spawned. This process eleminates the selection that is so crucial in the population. It removes the choosing process, which maybe filtering out the weak ones. Strong males that can compete, swim well will get the female that has the most eggs, spreading its strong gene in the end. The largest male isn't necessarily the strongest male. If two fish are mated in the hatchery simply because they are big, the offspring just might not be the strongest that can be produced.

2. The probability of two hatchery fish mating in the wild will correspond to the ratio of hatchery vs wild fish in the entire population. Someone else brought up that hatchery monitors the population to decide how many fish are raised, to eleminate the chance of two hatchery fish spawning. Right?

The above scenario can then be related to the likelihood of inbreeding.

Does this next statement make sense?

The chance of inbreeding (fish from the same parents mating) is smaller if more hatchery fish are produced? If 200 parents are used as opposed to 100, the chance that fish from the same parents meet up would be smaller right?

To further prevent inbreeding, would hatcheries choose a variety of spawners (big, small, skinny, fat, fish that make to the top, fish that only make it to the lower river) to mate?

Would this explain why a large system such as the Vedder is still able to be so productive in terms of quality and quantity since it has a large number of fish to work with originally?

That's all for now, it's Saturday night after all.

[Gooey]

Rod, question #1 you posed...you answered it yourself already: "hatchery raised juvenile would do better (re higher survival rate) in the first portion of the life cycle where natural selection is at work big time, so negative recessive alleles get a free ride into the population".   And may I ad you summed it up very nicely too!

You asked: "The chance of inbreeding (fish from the same parents mating) is smaller if more hatchery fish are produced? INCORRECT, its higher.  One naturally spawning pair may procude 6 returning adults.  take that same pair into a hatchery, and take their 3000 offspring, keep them in pens, feed them, protect them,  then release them once they are stronger and you get WAY WAY more returning fish from that brood!  More brothers and sisters in the river = higher chance of inbreeding = greater chance of negatives genes surfacing!

Thats why the vedder and chehalis have a 4 hatchery kill limit, they want to limit/minimize the number of hatchery fish from spawning!

[blaydRnr]

intellectually, i felt that the last couple of posts, to be very exhausting.  biology, fortunately is not my background.

in laimens term, i guess what it comes down to is.......

 the process of natural selection has been going on for millions of years. any attempt to 'short cut' or even interfere with its course can create an imbalance in the final out come. any harm or mistakes, may prove irreparable.
 
 

[Gooey]

Out of curiousity Blade, whats the highest level of education you have achieved?

[Buckeye]

More brothers and sisters in the river = higher chance of inbreeding = greater chance of negatives genes surfacing!

Thats why the vedder and chehalis have a 4 hatchery kill limit, they want to limit/minimize the number of hatchery fish from spawning!

Typically, different populations of the same species harbor different recessive deleterious alleles, so hybrid offspring between parents from the two populations (in this case hatchery and wild) will not be homozygous for the same deleterious alleles. The offspring are fitter than either parent because the effects of the deleterious alleles have been masked. If the hybrid offspring are allowed to mate randomly in subsequent generations, the deleterious alleles will segregate out because of the mechanics of Mendelian inheritance and produce individuals homozygous for the same deleterious allele, which will have reduced fitness. But the mean level of fitness in the population will still be higher than the level in either parental population, because the frequency of each deleterious allele has been reduced by mixing.



uhmm... I went to grade ten, does my post stil count?
 

j/k

[Rodney]

Gooey: Good point regarding higher return of spawners from hatchery parents than wild parents, I did not factor that in. But, how many more returning spawners would we get from a hatchery pair than a wild pair? Double?

The definition of inbreeding also needs to be clarified. Is inbreeding simply mating of offsprings from the same parents? Or are we assuming inbreeding as mating between hatchery offsprings?

If it is mating between offsprings from the same parents, the probability of a brother and a sister coming together also depends on the overall population size (bigger the population, smaller chance). If inbreeding is mating of all hatchery offsprings together, then your explanation regarding bigger hatchery population = higher chance of inbreeding would definitely be true.

Buckeye: The first portion of your post "Typically, different populations of the same species harbor different recessive deleterious alleles, so hybrid offspring between parents from the two populations (in this case hatchery and wild) will not be homozygous for the same deleterious alleles." doesn't seem too correct. Are hatchery and wild offsprings so genetically different that we can classify them as two different populations? Since both wild and hatchery offsprings come from the same population (hatchery offsprings from wild broodstock), how can they end up with different recessive deleterious alleles?

Population is defined as a group of organisms that inhabit a space and do not interbreed with other groups. For example, limnetic three-spine stickebacks come in two different varieties due to changes during post-glacial period. One group only occupies top water-column while the other occupies the bottom water-column. When putting both populations into the same fish tank, they do not interbreed as both exhibit different sexual dimorphism (they both exhibit different physical attributes (mainly size) that make them not interested at each other). The difference in those physical attributes is a product of evolution of genes during the last glacial period when they were separated.

Because the hatchery and wild groups are so similar genetically and physically, you can't classify them as two populations as they still breed with each other.

[FishiN AddicT]

Out of curiousity Blade, whats the highest level of education you have achieved?

One's level of intelligence and knowledge on a given subject is not limited by or directly linked to their level of education.  Personally, I think the education system in this country is a farce and one's level attained in that system is meaningless.

I must agree with gman!  One's level of education doesn't mean much.  Common sense or knowledge of any subject can be achieved without earning a degree in University/College.  Anybody can learn anything as long as their willing and have the passion to learn.  There are so many sources to obtain info about anything (computers, libraries, friends, etc.)

Like i said b4......Gooey.....why do you need to try and put others down?  If Blade is wrong.......why don't you correct him and explain otherwise.  I don't see Rod asking you if you're a moron........even if he disagrees with some of the things you say.

Sorry Rod for the last statement......this guy's such a downer  

[Gooey]

First off, asking one what level of education they have should not be seen as an insult (sorry if it was).  The main reason I asked, was that much the information I was drawing back on was from biology in grades 11 and 12 so I was just trying to find out were blade sat in that mix.   I absolutely agree that passion, ambition, and drive will take a person a long way too.  

Rod and I were getting into a fairly indepth conversation and if it would have been beneficail ( to the forum) to dial back the technical lingo...I could have.  I usually look at someones profile before I respond to them.  I notice many people 30 and above and not many teens...I think many of the members in their teens and early 20's arent putting their ages on their profile so it is hard to know what age of person you are talking to and you cant taylor/temper what you are saying quite as well.  

Any how...back to genetics!

Rod you are correct: "Since both wild and hatchery offsprings come from the same population (hatchery offsprings from wild broodstock), how can they end up with different recessive deleterious alleles"?

If hatcheris mixed the source of the gametes ie sperm from males of one river and eggs from a female from another system then infact the offspring would probably indeed be MORE competative.  this is a theory known as hybrid vigor.  Basically is dictates that when 2 different populations are cross bread, the strongest traits in each gene pool would be expressed in the offspring.  Unfortunately I dont think hatcheries mix their gamete sources (they all come from on river/one population).

[Gooey]

Just spoke with the cap hatchery and return rates (% of hatched fish that make it back as adults) ranges between .5-7 percent.  Wild fish are on the lower end of that spectrum as compared to hatchery.

Thats quite a difference (14Xs) if you take either extreme.  On a batch of 2000 eggs, thats 10 wild adults (.5%) compared to 140 hatchery adults (7%).

WOW

[blaydRnr]

Out of curiousity Blade, whats the highest level of education you have achieved?

In Biology,  grade 12 (barely passed).

In marketing and business administration,   post secondary (college and university).

In the school of 'hard knocks',  still learning.

.....what's your point. How far did you go?

[Gooey]

same sorta story...all over the board in high school, took math11 3 times to get a high enough grade for college, at the same time pulled A's in the sciences.  After that 3 years general science, 2.5 Business... none of my education is particularly applied to my current employment but none the less valuable to who I am as a whole.  In the last 2.5 years I have had 2 additions to my family, ask me what the has taught me about life!

A lot of what we were talking about was from bio 11 (punnetts square etc) and indeed I read most of those post more than 2 times before replying!  I would like to get feedback from someone with a more current involvement in the genetics fields as I am rusty and the field of genetics is still exponentially growing.  

If indeed this conversation is too technical then it would be best to dial back the techi talk so more can benefit from the dialog!  Really what we are talking about, IMFO, is quite fascinating and I wouldnt want to loose someone with all the jargon etc.  Maybe I am drawing on more of my university genetics than Highschool Bio!