USGS Study of Brookie Genetics

[Chaz]

I found this in s study of brook trout genetics done by USGS. It gives credence to no stocking over wild populations.

"Stream populations that are very close geographically may be very different genetically because geographic separation of the drainages has isolated them (reproductively) for millions of years. For example, in western Maryland, two brook trout populations in streams separated by a ridge and only a few kilometers drain into the Potomac (Atlantic slope) and Ohio (interior) River watersheds, respectively. These two populations are as genetically differentiated as Atlantic salmon from Europe and North America."

"•Stocking has left a definite imprint on some of the studied populations. Microsatellite techniques have demonstrated that fish introduced from a major drainage, a stream, or even a particular hatchery can be discerned. In some cases, translocated fish have successfully mated and imported (introgressed) their genes into native populations."


From "Brook Trout Genetics Whitepaper"
By
Dr. Tim King
U.S. Geological Survey, Biological Resources Division, Leetown Science Center, Kearneysville, West Virginia 25430

 

[JackM]

I miss your point, Chaz. How does this "give credence to no stocking over wild populations?"

I assume you are focused on this sentence: "In some cases, translocated fish have successfully mated and imported (introgressed) their genes into native populations."

I think what this sentence does is debunk the theory that hatchery trout cannot survive in the wild and spawn because they are inferior.

 

[OhioOutdoorsman]

Chaz, from what I understand of puplation genetics, this could be a very important issue. If we want to talk the ability of a brook trout population to survive a catastophic event (acid mine runoff, forest fire, sudden polution, drought, etc) having diverse genetics is the key. If an already isolated population (like most brook trout)becomes genetically homogenized by stocking, it could be a recipe for disaster........

I have noticed that the PFBC seems to only stock brook trout over predominately brook trout watersheds and this has been a potential concern of mine.

Jack, I agree, I have never bought into this theory that stocked fish are incapable or even signifigantly inferior.....one just has to look at a state full of brown trout that didn't exist 150 years ago to see that this is false. I don't know that Chaz was arguing that point though.

 

[Kendal]

Thanks for bringing this article to my attention. The author's conclusions seem reasonable and are actually rather tentative.

As for stocking over wild populations, it depends first on the condition of the wild population and why it got that way, and second on the source of the stocking--too many variables unless you have a specific popluation in mind. This can be gleaned from many years of research, including the article under discussion.

If the source of the stocking is your typical PA fish commission hatchery adult, in most cases that seems dubious.

This topic might be more aptly located in the conservation thread.

 

[troutbert]

I've heard of brook trout genetic studies in Tennessee, New York, and I believe NH. But I've never heard of this type of study in PA. And I don't know why. PA certainly has a lot of brook trout water.

Now even West Virginia has beat us on this one. That really stings!

 

[Cynic]

Chaz's post:

"•Stocking has left a definite imprint on some of the studied populations. Microsatellite techniques have demonstrated that fish introduced from a major drainage, a stream, or even a particular hatchery can be discerned. In some cases, translocated fish have successfully mated and imported (introgressed) their genes into native populations."

Jack M/'s post:

"I think what this sentence does is debunk the theory that hatchery trout cannot survive in the wild and spawn because they are inferior."

I think the sentence before the last sentence should be considered. If my cynically mind interprets its meaning correctly, I would say that the sentence does not tell us whether the brook trout were "stocked" from a major drainage, a stream, or a hatchery or how many came from each mentioned source.

I think that the work "stocking" as it is used in the above (first) paragraph, means translocating the brook trout from one, or is it from two, or is it from three of the sources cited.

 

[JackM]

I agree the quoted material was ambiguous as to whether the crossing genetically involved hatchery plants, but I was also trying to interpret why Chaz' thought it lent "credence" to the idea of not stocking over wild pops and it seemed what he meant was that it would support the idea that hatchery trout genes would be introduced into the wild population by cross-breeding.

 

[SlumpBuster]

Didn't read the report yet but will and will post more when I finish it but.

"I have noticed that the PFBC seems to only stock brook trout over predominately brook trout watersheds and this has been a potential concern of mine."

Not true they seem to like to stock Rainbows over them as well.

Secondly on the idea of the genetics being crossed can be a major problem making some strains more susceptible to disease but it can also make others less susceptible. I think the point though is that these genes that are being imported into the population and do not belong. If the genes did they would have evolved. If they have not evolved then the strain of brook trout if unique for a certian reason. I think is is important to keep these strains unique before we get one single strain of brook trout that could be wiped out by a disease.

 

[JackM]

Chaz wrote on another thread:

"Jack, When I posted the message about the Brook trout DNA I posted the link, I am pretty sure you didn't read the study because your comment was something related to stocked trout surviving to spawn. That' wasn't even the point of the study if you read it you would know. Your comments with regard to conservation issues are as knee jurk as others are, in fact I can predict your response nearly every time. Read the study them comment on it, or don't comment at all. The whole reason I posted the message was so that every would have the study as a resource. This is only the latest instance. Your respnses to the post about McCoy dam, show you are not interested in the truth. I've kept informed about the issue, maybe not as much as some others here, but know enough not to trust our elected officials on this issue, particularly the representative from Centre County."

Chaz, where is a link to a study? Was this the thread you were talking about?

 

[Wulff-Man]

He gave the name of the study. Google it and you will find the link: Brook Trout Genetics Paper

 

[JackM]

Wulff-Man wrote:
He gave the name of the study. Google it and you will find the link: Brook Trout Genetics Paper

Thanks. At least you actually posted a link. So now that I have had time to read the "white paper," could anyone, including Chaz, let me know what part of any of my prior statements and comments are inaccurate?

 

[FarmerDave]

Jack, I only skimmed over this thread and only skimmed over the report, but I'll respond. I hope I am not off base, but if I am, I apologize. Like I said, I only skimmed the thread.

Anyone who says hatchery fish can't survive in a trout stream is blowing smoke up your butt.

For the sake of argument: Lets say they can't survive the winter (which some do). We know that some survive the summer in colder streams, and the fish commission even stocks some fish in September (or they used to). These stocked brook trout are equipped for reproduction, and they can breed with other stocked trout and can cross breed with the natives as well. I know, cross breed is a poor choice of words because they are all brook trout.

I didn't read the entire report, or whether or not it says they can't survive. I doubt it did. But I do know of a brook trout genetic study that compares the population of 3 streams to determine if one population was indeed native. the stream in question is in Ohio, and so is one other stream in the study who’s population is known to be from a hatchery strain (Quebec). that's right, a wild population derived from hatchery fish. I used to have a hard copy of at least part of the study (may still have it), and I think I may have even sent a copy of it to Chaz, years ago.

All that said, the hatchery fish stocked in PA are inferior because they have been selectively bred for maximum output in a hatchery environment.

OK, lets say a population has been compromised (for lack of a better term on such short notice). As long as the original genetics are still present, and they stop stocking, mother nature will sort out what is best for that specific environment. It might be something different from the original uncompromised strain, but the strongest traits for that environment will come forward. That was one of the arguments about Big Spring and the planting of hatchery brook trout after the hatchery was closed. Nature will select what is best from what is available. It's natural selection. But as long as they keep dumping the rubber fish over the natives, it is no longer natural selection, it's selective breeding by humans.

In other words, I think this is another apples and oranges discussion. :lol:

 

[Wulff-Man]

I really hate to get caught in the middle of this, but I can’t seem to help it. I feel like I’m being drawn like a moth to the flame (no pun intended). I believe what Chaz is saying is that he posted a study on the potential negative effects of cross-breeding native strains of brook trout with stocked trout, and Jack hi-jacked the subject to bring up an issue or argument concerning the ability of stocked (hatchery) trout to survive and breed in the wild.

Jack asked how the study gives credence to no stocking over native populations. Here are a few excerpts that may answer this:

“According to Professor E.O. Wilson at Harvard University, current extinction rates are at the highest levels known to science. In addition to the loss of entire species, populations and the genetic diversity they contain – the building blocks of species – are rapidly disappearing. Genetic variation constitutes the most fundamental component of species diversity. When a species loses genetic diversity, its ability to adapt to changing environmental conditions is diminished. Furthermore, diversity provides the ability for populations to adapt to local conditions. In short, genetic diversity must be preserved for short and long-term survival of species.”

“Recommendations to managers include the need for great caution before moving brook trout between river drainages, and the recommendation that supplemental stocking should proceed conservatively and be based on local broodstock collections. Remaining genetic diversity should be protected wherever possible.”

Note that this applies to any stocking, not just of hatchery trout.

 

[JackM]

I don't think I hijacked anything. Chaz posted two quotes, not a link, and said that it "lent credence, etc." I read the quotes and commented that they seemed to suggest that hatchery plants sometimes inter-breed the wild strains and that this debunked the oft stated assumption that hatchery trout don't survive well, nor spawn successfully. I also queried why Chaz thought this "lent credence, etc." and you may notice he never replied. Someone else asked me to clarify my point and I did so.

Now, having read the whole paper and your additional selected quotes, I can say more about it, but I don't want to hijack this otherwise interesting and informative thread.

 

[FarmerDave]

That's funny Jack. you say you didn't hi-jack the thred, then you go on to say how you did it. (I'm teasing)

WM, I alway cring when people use diversity in these types of discussions and here is why.

Translocating trout to a stream that already has a native population actually adds to the genetic diversity. Short term at least.

 

[Wulff-Man]

FarmerDave wrote:
WM, I alway cring when people use diversity in these types of discussions and here is why.

Translocating trout to a stream that already has a native population actually adds to the genetic diversity. Short term at least.

Yeah, FD, that had me scratching my head a bit, too. I guess the main point is that each population evolves to survive best in its own environment, and introducing genetics from other strains messes with the equilibrium. It's probably also a risk that over the long term all strains may start to all become more alike, and therefore less able to survive in their own environment.

 

[JackM]

FarmerDave wrote:
That's funny Jack. you say you didn't hi-jack the thred, then you go on to say how you did it. (I'm teasing)

I know you said you're teasing, but I don't think of continuing a discussion or questioning a point under discussion as "hijacking."

 

[FarmerDave]

Wulff-Man wrote:

FarmerDave wrote:
WM, I alway cring when people use diversity in these types of discussions and here is why.

Translocating trout to a stream that already has a native population actually adds to the genetic diversity. Short term at least.

Yeah, FD, that had me scratching my head a bit, too. I guess the main point is that each population evolves to survive best in its own environment, and introducing genetics from other strains messes with the equilibrium. It's probably also a risk that over the long term all strains may start to all become more alike, and therefore less able to survive in their own environment.

Hmmm. I think I get it now. You can actually have more diversity in indiviual streams while decreasing the diversity from stream to stream. In the event of a widespread environmental change, the species is less likely to survive because there is less diversity between populations. Makes sense. I guess i will have to read the report again (more thoroughly this time. My head hurts.

I was looking at it from a micro level

P.S. Cut it out Jack.

 

[JackM]

Ladies and gentlemen, the pilot has just informed me that the crisis is over and we are back on track to our original destination, which is where we started, or in other words, nowhere. :-o

 

[Chaz]

Jack do a Google search you'll find the study. One of the main points was that the researches could pinpoint where the transferred trout came from, for instance, “stocking has left a definite imprint on some of the studied populations. Microsatellite techniques have demonstrated that fish introduced from a major drainage, a stream, or even a particular hatchery can be discerned."
Another point was that managers should be very careful when trying to restore a population of trout because with this new method they can find out what the differences are between populations and that the differences can be major even for populations that are geographically very near each other.