Triploids

[cgyguy]

Intersting article in the Columbia Valley Pioneer (Invermere BC)

 

A few of us have reviewed the stocking

lists for 31 lakes from Parsons to the

White River and to our surprise found

the Provincial government has allowed

the Fisheries Society to stock predominately

triploid (genetically modified) fish.

Over 320,000 triploids were placed in the

lakes with another 69,000 planned for

this year. They are touted as sterile fish

to help out our wild stocks — recent research

indicates differently.

Just as farmed fish escape, triploids

in lakes do the same. Of the 31 lakes

reviewed, 21 have outlets flowing into

mainstream waters. These genetically

modified fish are now able to enter our

stream populations, competing for the

same food and space as our wild stocks.

Growing larger more quickly they

consume more food, taking away from

the resident population. Present research

shows wild fish are experiencing new

stresses with global warming, through

warmer waters and changes within their

habitat. In order to adapt they need time,

and where triploids have escaped into

these environments, wild stocks are further

stressed.

In our area two species of fish, the

Westslope Cutthroat and the Bull Trout,

are both blue-listed species (international

endangered species rating), and a concern

due to their numbers.

“Ah so what, our redneck trout can

hold their own”! Remember we have

been told that triploids are sterile fish –

well guess what, they’re not. The processes

used to create triploids have a 98 per

cent success rate, leaving 2 per cent able

to breed. And no one is checking every

triploid for sterility. So over the past five

years 6,500 genetically modified fish capable

of mating have mixed with our wild

stocks, including the blue listed ones. But

are more fish good?

Researchers at Purdue University

in the USA have come up with startling

information. While the triploiding of

fish makes them larger and thus more

attractive in a reproducing population,

their offspring were less likely to survive.

Knowing this the Purdue team, using a

computer modeling program, took a

60,000 wild fish population and placed

60 triploid fish capable of breeding into

the population. They found that within

40 generations both the triploid cross and

wild populations went extinct.

The researchers stated in their report,

“A population invaded by a few genetically

modified individuals would be more

and more transgenic [capable of transferring

a gene], and as it did the population

would get smaller and smaller.”

The sad point is the entire stocking

program for the rest of B.C. fresh waters

is the same as ours and biologists are too

busy to talk! If you are alarmed and want

to share your thoughts here are a couple

of names: B.C. Minister of Environment:

Hon. Terry Lake, env.minister@gov.bc.ca

Fisheries & Oceans Canada: Hon.

Gail Shea, min@dfo-mpo.gc.ca

[troutlover]

Im sure the government knows all this and would never comprimise the stability of our natural river systems and their native species.

[headscan]

Im sure the government knows all this and would never comprimise the stability of our natural river systems and their native species.

There really needs to be a sarcasm emoticon. You know someone is probably furiously typing a reply right now asking how you can be so naive to think something like that...

[ironfly]

cgyguy, can you provide a link to that study from Purdue? Or maybe some other information that explains why triploid minnows are less likely to survive, and why hybridization results in population collapse. I'm very curious, and a little skeptical. After all, mutts are usually stronger than either parent, right? I'm not saying I support stocking triploids, just that I need to be armed with information if I'm going to fight for something.

[cgyguy]

cgyguy, can you provide a link to that study from Purdue? Or maybe some other information that explains why triploid minnows are less likely to survive, and why hybridization results in population collapse. I'm very curious, and a little skeptical. After all, mutts are usually stronger than either parent, right? I'm not saying I support stocking triploids, just that I need to be armed with information if I'm going to fight for something.

Junior - I copied this from the ColumbiaValleyPioneer.com. There are some contacts at the bottom of the page, not sure if that would help. I find the read interesting but also am skeptikal and a little cautious as well. Cheers

[monger]

In the same way that triploids can potentially escape to join a breeding population...so can a stocked diploid that does not have the local genetic history. So stocked diploid rainbows could be entering the local system and causing havoc. Is there any concern/evidence of escaped diploid stockers?

I have seen rainbows and Cutt/bows in Elk River tributaries. Genetic pollution is already occurring on the Elk. Furthermore I have been Brook trout in Michele Cr. More pollution aimed at Bull trout.

Us humans certainly have a way with screwing up things.

I guess time will tell if the computer modelling is anywhere near accurate. Modelling and reality often aren't that close since there is so many factors to consider.

[DonAndersen]

Don't you just loved hyperbole.

 

Like "The processes

used to create triploids have a 98 per

cent success rate, leaving 2 per cent able

to breed. And no one is checking every

triploid for sterility. So over the past five

years 6,500 genetically modified fish capable

of mating have mixed with our wild

stocks, including the blue listed ones."

 

What this idiot of a newspaper writer it trying tell you is that every fish that is not sterile made it successfully into the native populations. A lot of these lakes have the potential to dump into a downstream water course. All it takes is a 1:1000 year flood.

 

He/she probably worked for Global @ one time.

 

 

Don

 

[PGK]

.

[Flyfisher]

In the same way that triploids can potentially escape to join a breeding population...so can a stocked diploid that does not have the local genetic history. So stocked diploid rainbows could be entering the local system and causing havoc. Is there any concern/evidence of escaped diploid stockers?

I have seen rainbows and Cutt/bows in Elk River tributaries. Genetic pollution is already occurring on the Elk. Furthermore I have been Brook trout in Michele Cr. More pollution aimed at Bull trout.

Us humans certainly have a way with screwing up things.

I guess time will tell if the computer modelling is anywhere near accurate. Modelling and reality often aren't that close since there is so many factors to consider.

 

 

In the same way that triploids can potentially escape to join a breeding population...so can a stocked diploid that does not have the local genetic history. So stocked diploid rainbows could be entering the local system and causing havoc. Is there any concern/evidence of escaped diploid stockers?

 

Excellent point monger. Far better for wild fish to stock triploids rather than diploids in lakes like we did in the past. The fish stocked in BC lakes are not genetically suited to riverine habitat anyway, they are lake fish. It's unlikely they would move from a lake habitat into a stream in numbers that would compete for food with wild native fish. There are much more immediate pressing concerns negatively impacting wild fish stocks than this.

[danhunt]

These genetically

modified fish are now able to enter our

stream populations, competing for the

same food and space as our wild stocks.

Growing larger more quickly they

consume more food, taking away from

the resident population.

 

By definition a triploid has an extra chromosome, so instead of a female XX or male XY you have XXX or XXY, which is what renders them infertile. They aren't more agressive, they grow larger faster than their diploid counterparts because their bodies don't have to spend resources on developing mature sexual organs.

 

The processes

used to create triploids have a 98 per

cent success rate, leaving 2 per cent able

to breed. And no one is checking every

triploid for sterility. So over the past five

years 6,500 genetically modified fish capable

of mating have mixed with our wild

stocks, including the blue listed ones.

 

It is my understanding that the reason 2% remain fertile is because the shocking process used to create triploids doesn't work, so you effectively have the same diploid hatchery fish that were stocked for decades.

 

Researchers at Purdue University

in the USA have come up with startling

information. While the triploiding of

fish makes them larger and thus more

attractive in a reproducing population,

their offspring were less likely to survive.

Knowing this the Purdue team, using a

computer modeling program, took a

60,000 wild fish population and placed

60 triploid fish capable of breeding into

the population. They found that within

40 generations both the triploid cross and

wild populations went extinct.

The researchers stated in their report,

“A population invaded by a few genetically

modified individuals would be more

and more transgenic [capable of transferring

a gene], and as it did the population

would get smaller and smaller.”

 

Faulty logic, triploids can't reproduce. They can develop spawning colors and exhibit spawing behaviors that could disrupt wild fish, but they can't pass on genetic material. If the afore mentioned 2% were to interbreed with wild fish then it is true their offspring would be less likely to survive, but because hatchery fish of any stripe are genetically inferior to wild stocks. Old news.

 

By stocking triploids there is 98% less chance that hatchery fish will interbreed with wild populations, which is what will ultimately destroy them. Assuming stocking non-native diploids is out of the question, the only other alternatives are to stock diploid native species that will freely interbreed with wild populations and reduce their genetic fitness or to stop all stocking programs immediately.

 

There is a kernel of truth behind the article, but either the author doesn't have a grasp of genetics or the information has been sensationalized to sell more copy.

[DonAndersen]

But,

 

There are triploids and triploids.

 

BC stocks 3NAF = 3N [extra chromosome] AF [all female]

 

Alberta stocks 3N [extra chromosome only]

 

Difference - 3NAF have no jacking males in the population that exhibit spawning colors or behaviors with 1/2 of them dying @ age 2.

 

Don

[dryfly]

Some clues as to the probable high BS factor in the article.

 

1) "computer modeling program" ... they can be made to prove whatever you want.

2) "global warming" .. which explains total destruction of the universe ... well, or not. See here.

 

The whole article falls under the same scientific category as "if my aunt had balls she's be my uncle."

 

Everything we do has risks. If we stopped imposing risks we'd stop living.

 

 

 

[PGK]

.

[danhunt]

The article is pretty accurate. Stocking AF3N only gives you one more safety net. The AF process is even less reliable than the triploidy process (it's temperature driven). In any given 10,000 fish stocking, there will be a few dozen fish capable of reproducing. If they do escape, they will breed with wild stock and they will have some kind of effect. In my opinion, the majority of stocked lakes in BC take this into account and stockings are fairly well planned. I have a lot of opinions on fish stocking, but they aren't related to the context of the article. The argument about 'lake fish vs river fish' doesn't hold because there are multiple strains of fish stocked in BC, one of the most common being Pennask strain, which show a very common small stream body form and are one of the most adaptable strains in the province.

 

PGK, I'm sorry if it seems like I'm attacking your posts because that is not my intention. It is just that you are making points that I don't agree with, even though I generally agree with your intent as I understand it.

 

You're right, triploids only provide an additional measure of safety, thats all they can do. But I think the point of the article is that genetically modified fish could interbreed with wild populations, but it is physically impossible. A triploid fish cannot breed, the fish that remain reproductively viable are the ones where the process didn't take, so they remain genetically unmodified hatchery fish. That is not a good thing either, but it is a different issue.

[ironfly]

I also have a hard time understanding how a hatchery fish is so genetically inferior to a wild fish. Hatchery fish originally come from wild stocks. It's not like we made them out of Play-doh. How can ten or twenty generations in a hatchery have much influence on millions of years of evolution? If this is true, and they are inferior, it stands to reason that very few escapees would actually survive to spawn. Yet rainbows have somehow managed to establish stable breeding populations all over the world. So either they can't survive and are no threat, or they're very adaptable and successful, and not a threat.

 

As some have said, our wild fish have much bigger threats than this. I haven't heard much talk about Snakeheads, but they're being sold alive in BC.

[reevesr1]

I also have a hard time understanding how a hatchery fish is so genetically inferior to a wild fish. Hatchery fish originally come from wild stocks. It's not like we made them out of Play-doh. How can ten or twenty generations in a hatchery have much influence on millions of years of evolution?

I am in no way a geneticist, but I do know that I have seen a couple of documentaries on breeding for domestication. You can selectively breed desired traits in to a population in far less than 20 generations. There was a really cool documentary where they bred foxes in Russia I think and in just a few generations they looked, barked, and acted more like domestic dogs than foxes. Don't know how that would apply to hatchery fish, but to say that the fish could not be significantly different that a wild fish in 10 or 20 generations may not be correct.

[danhunt]

I’m not sure I can do it justice, but it is basically because the natural selection processes that have developed over thousands of years in the wild can’t be duplicated by hatcheries. In the wild the “best and brightest” tend to mate with one another, which increases the chances they will pass on their favourable traits to their offspring. In hatcheries, on the other hand, they tend to take two fish at random from the same area that are sexually mature at the same time and mix their eggs and sperm. It’s like comparing a pure breed with the Heinz 57 at the pound. The mutt might be fine as a family pet, but a dismal failure as a working dog.

[PGK]

.

[Garhan]

I know that I wouldn't put as much stock into computer modelling. Maybe in a best case scenerio some thing like this ***might** happen. There are to many unaccountable variables in this situation to find very much truth to this type of conclusion. Remember this is only a computer model.

[DonAndersen]

Folks,

 

For those that wish to be informed by experts in fish culture should look @ what BC does in this document.

 

http://www.gofishbc.com/docs/2208A06B4B85CFDB.pdf

 

 

regards,

 

 

Don

[ironfly]

I’m not sure I can do it justice, but it is basically because the natural selection processes that have developed over thousands of years in the wild can’t be duplicated by hatcheries. In the wild the “best and brightest” tend to mate with one another, which increases the chances they will pass on their favourable traits to their offspring. In hatcheries, on the other hand, they tend to take two fish at random from the same area that are sexually mature at the same time and mix their eggs and sperm. It’s like comparing a pure breed with the Heinz 57 at the pound. The mutt might be fine as a family pet, but a dismal failure as a working dog.

I couldn't disagree more about the purebred vs. mutt arguement. You couldn't pay me to take a purebred, under any circumstances. And I know half-a-dozen champion dog mushers who'd tell you the same. Also, a couple guys who work with search & rescue dogs, not to mention the lady I know who trains seeing-eye dogs.

[danhunt]

I couldn't disagree more about the purebred vs. mutt arguement. You couldn't pay me to take a purebred, under any circumstances. And I know half-a-dozen champion dog mushers who'd tell you the same. Also, a couple guys who work with search & rescue dogs, not to mention the lady I know who trains seeing-eye dogs.

 

Are they triploid sled dogs?

[Harps]

People here understand that stocked fish are closer to "domestic pure breeds" than wild fish. Right?

A pure fish in this instance is a fish that has evolved in a cerain situation for thousands of generations. No human selected traits, just traits that have allowed it to survive. Stocked fish haven't undergone that selection (most of the time).

 

In Danhunts instance, the purebred represents the wild selected fish, with traits allowing it to survive being passed on and other traits and mutations failing.

[monger]

I wonder if I can get a mutt to point pheasants for me....

[DonAndersen]

Harps,

 

In Alberta, you're right. The rainbows here share traits with Herefords.

 

In BC, wild stocks are used as egg sources in some cases. In others, wild stocks are added to the mix regularly.

 

The difference is related to the statement made by a bio. from BC who said right out loud " the fishing in BC is better than it was 30 years ago". BC has some idea of what it's doing to improve the lake fishing. In Alberta - well!

 

Don