Pond Boss Forums STOCKING A NEW POND Types of fish to choose F1 outbreeding depression?

Folks, experts, I just read this on the Mississippi Farm Pond site and would like any comments from people who have actually read any reports of studies verifying this.

http://www.mdwfp.com/forums/topic.asp?TOPIC_ID=56840

thanks

Even though Northern & Fla LMB are the same species, they ARE subspecies with notable differences (both good and bad, depending on one's location and goals).

F1 LMB have 50% Northern genes and 50% Fla genes. Fx offpsring resulting from the F1s will not have a 50-50 mix of genes and traits; as a result some of the Fx LMB would be "inferior" compared to the F1s from most standpoints (although which mxitures of Fla & Northern genes in the Fx bass are inferior would depend on your location & goals).

If left alone, surviving Fx offspring in the out years would tend to have whatever mix of Northern & Fla genes that did the best in a particular BOW (based on conditions there & management practices). I believe it is the desire to maintain the full spectrum of both Northern AND Fla genes in a bass population that lead many PMs (ewest, for example, IIRC) to stock both Northern and FLa Bass in addition to F1s so that both sets of genes are introduced into bass offspring in the out years.

BM , Theo is right. Like to hear Ewest comments.

First point is I feel genetics fall way behind management if growth rate is a concern. In other words you stock F1’s for the pond b/c you want “good” growth and aggressive bass. The Fx bass may not be as aggressive or may not have as good of growth rate??? Is the growth limited by these genetics. In most of my clients ponds it would not be it would be from lack of maximum management (forage diversity, water quality, primary production, competition, etc. you guys know what I mean). Further more if a bass shows lower growth rates then this would be indicated by his Wr you should be tracking and simply pull him out. So you achieve desired results.

I disagree with the advice to not stock them b/c they fit the bill rather well for most. If you want a fly fishing pond with super aggressive bass stock northern, if you want next world record stock pure Florida. If you want best of both worlds F1 is easy. If you want to stock both subspecies instead go for tht but logistically not easy and then in couple of years you have same mixing of genetics you would if you had stocked the F1’s.

I will post on this more later but will say for now that BM ask the right question which was not answered. In the many studies on this topic that I have read and studied I have never seen any evidence of nor anyone suggest that F-1s (same species cross) exhibit outbreeding depression. I will point out that there is a natural range (area) of Fla and Nort LMB overlap where F-1 crosses occur in lakes , rivers and ponds. I have not heard of anyone in that geographical area saying that they are encountering outbreeding depression. This needs further research and study on my part to consider the full answer. It is evident from what I have read that there are opinion biases at work in the studies wrt LMB stocking , types ect.

I would be interested to hear if there is outbreeding depression when different breeds of cows or horses are crossed. One example given was "mutt dogs". I have serious doubts that is correct wrt dogs. They may be a mix of many dog breeds but that does not mean they are not as good or suffer from outbreeding depression.

ewest, IIRC the cattlemen who run Black Baldies are always breeding Black Angus (cows, I believe) to Polled Herefords (bull - who wants to deal with a Angus bull?) for each generation. They do not breed the "F1" black baldies and use the resulting Fx cattle. They want that hybrid vigor from the F1 Black Baldy mix.

I wish I knew more, but we stick just with the Polled Hereford side of the situation.

I will ask Fish Wife if she knows of any analogous or contrary breeding practices in horses.

---------------------------------------------------------------

Crossing domestic breeds is not exactly the same as crossing wild supspecies, but must be similar. Speculation follows:

WRT mutts in the dog world (it seems like this would apply for all domesticated animals as well), when two or more breeds are crossed, you are not dealing with natural occurring subspecies that have a full compliment of genes/traits optimized my Mother Nature for an environment. Domestic breeds IMHO contain subsets of the gene pool found in the natural speceis which was domesticated (the original wild horse, aurochs for cattle, or s species of desert wolf for domesticated dogs). "Mutts" obtained by crossing different subsets of those residual genes foten have a fuller, more diverse set of genes than either pure blood parent, frequently giving "hybrid vigor" in the form of the absence of pure bred problems such as hip dysplasia.

Here is the reply from the good professor. Way above my head:

Hi Jim – I posted this response to the forum as well.



First, let’s discuss how hybrid vigor works. Crossing two species or subspecies increases heterozygosity, or the likelihood of having dissimilar genes for any given trait. This may make the animal more fit in a changing environment because it may have genes for several environmental conditions (e.g., hot or cold tolerant). However, when F1 hybrids interbreed in successive generations, they become more and more homozygous, and the genes retained may not necessarily be the “best” for any given trait (e.g., slow growth, low aggression, etc.).



There is a fair amount of literature addressing introgression and outbreeding, which has been demonstrated with many species. There is no reason to believe F1 bass would be any different, so if the potential for regression is there, we (Extension) must approach these stockings with caution. It doesn’t mean that someone who wants to intensively manage their pond can’t use these fish as a management tool. However, it would not be a good idea for not-so-intensive managers to stock ponds with F1 hybrids and expect to have excellent growth 20 years later.



I list a few studies that you can check out below. You’ll notice similar names on all of the papers because they are the primary researchers working with bass genetics. One study that addressed the potential for outbreeding depression is:



Philipp, D. P., J. E. Claussen, T. W. Kassler, and J. M. Epifanio. 2002. Mixing stocks of largemouth bass reduces fitness through outbreeding depression. Pages 349-363 in D. P. Philipp and M. S. Ridgeway, editors. Black bass: ecology, conservation, and management. American Fisheries Society, Symposium 31, Bethesda, Maryland.



This study did not directly test the outbreeding depression of F1 hybrids – instead it looked at the effect of stocking one genetic stock on the other. However, the mechanism is the same.



Dave Philipp had several earlier papers that addressed the potential for later generation intergrades to have reduced performance:



Philipp, D. P. 1991. Genetic implications of introducing Florida largemouth bass. Canadian Journal of Fisheries and Aquatic Sciences 48 (Supplement 1):58-65.



Philipp, D. P. 1992. Stocking Florida largemouth bass outside its native range. Transactions of the American Fisheries Society 121:688-691.



Philipp, D. P., and G. S. Whitt. 1991. Survival and growth of northern, Florida, and reciprocal F1 hybrid largemouth bass in Central Illinois. Transactions of the American Fisheries Society 120:58-64.



Another paper that I recommend is:



Kassler, T. W., J. B. Koppelman, T. J. Near, et al. 2002. Molecular and morphological analyses of the black basses: implications for taxonomy and conservation. Pages 291-322 in D. P. Philipp and M. S. Ridgeway, editors. Black bass: ecology, conservation, and management. American Fisheries Society, Symposium 31, Bethesda, Maryland.



In this manuscript, the authors offer substantial evidence that suggests “Florida bass” and “largemouth bass” are two separate species.



As for mixing coppernose and regular bluegill, the same mechanism are present to lead to outbreeding depression, but I have not see anyone address this. However, with both hybrids, it is reasonable to suggest that the effects of outbreeding depression in the Deep South would be less noticeable than in the north. For instance, Florida alleles may be more of a hindrance in Ohio than southern Mississippi. But this has not be testing directly.









From: Jim Burkes [mailto:j.burkes@sbcglobal.net]
Sent: Monday, December 08, 2008 9:45 PM
To: Wes Neal
Subject: F1 outbreeding problems



Mr. Neal, I just read about this phenomena on the farm pond forum and posted this response:

I have read consideraby about northern vs. fla. vs F1 and this is the 1st time have seen any mention of this regression of quality bass traits. I would think since they are effectively the same species, this would not occur. I can see that this outbreeding regression would occur, as in HBG, but does this also occur in a mixed population of CNBG and standard BG? Has there been any studies with empirical evidence of this taking place? I will have to post this on the "Pond Boss" forum and get feedback from the many fisheries experts who frequent that forum.

Again,I would like to have the oportunity to read any available studies, since I just stocked F1s in my pond, even though their primary function will be control of BG for trophy BG fishing. I also stocked a 50/50 mixture of CNBG and BG as suggested by most authorities, my pond being in south Ms.



Do you have more information?



thanks for your time,

Jim Burkes

Guess I'm stuck with my mutt bass and perch. I may have to do some managing. Cecil get the backdrop and props ready for the 2# 'mutt' bluegill.

This is a great topic! Thanks for bringing it up Burgermeister.

I was considering adding a few F1's to my pond just for fun, but now I'm thinking that might not be the best idea in my case.

Its not often I post a warning on things but this is one. Don't believe everything you read. I have read all of those studies and more which were not cited. There are at least 2 camps in the scientific community on this and they do not agree with each other.

I doubt very seriously that the fisheries scientists ( quite a few of them) in private fisheries mgt who produce and use F-1s would agree with the above analysis. I know I don't. Much of what was said can be said of any captive population of LMB. I think that analysis fits right in with the "opinion biases at work in the studies wrt LMB stocking , types ect". Only one side of the info is presented.

I will dig out the research and post afterward.

I'm reading this with strong interest obviously it effects me to a high degree. However does anyone understand my point?

Weissguy you are perfect example through this little post you are thinking of changing of not stockign a bass that has resulted in wonderful growth and catch rates for my clients. If you read the above "the professor" is worried about things 20 years from now. Make sense.

Be aware of this current research but take it with a grain of salt and take time to understand how does this really effect my pond goals? We currently stock northern, F1 and Florida bass for clients and might emphasis this "mixing" more but to be scared of an F1 due to this limited knowledge could hurt clients overall goals I feel. Does anyone agree?

Yep. Adding new genetics in the future (and in my thinking, this is on the order of a decade ahead) should take care of any possible problems. And ANY population of fish - pure bloods, F1's, mutts, or fancy mixes - could probably benefit from fresh blood downstream at some point.

I wanted northerns, due to their catchability. I want large BG, but not hordes of runt bass. Since I had to stock out of season(BG in spring and bass in summer) I had choice of Fl., which I did not want due to catch rate, or F1s. Hopefully, I will get the hybrid? vigor from the CN/BG mix. I may as well go for the trifecta and get some hybrid catfish.(CCxBC).

Do fatheads and golden shriner interbreed? Gambusia? ha!

BM I bet you will do just fine with what you have. If you get concerned just let me know and I will trade you some of my mutts (mix of Norts , Flas and F-1s). I will be posting more as I get through with the research review.

IMO this is a lot to do about some wild speculation. I do not believe that those conclusions can be drawn from the studies I have seen. None of them even address F-1 LMB. There is scientific politics being played out in that approach as I have posted in another thread.

I am not suggesting that Dr. Wes Neal is involved in the one-side vs. the other or fisheries politics. He is taking the proper ultra cautious extension approach and reporting what he has read and understands as he should. That is his job and we all appreciate his heads-up.

Theo I can always count on you to make me feel better.

First this is still a work in progress. Second the below can be read to contradict the conclusions in BM's post above as it relates to his pond which is in the intergrade zone. The premise is stocking F-1s (they are intergrades) into waters in the intergrade zone (an area naturally populated by LMB with both Fla and Northern genes) will not lead to a greater chance of outbreeding depression nor inbreeding (regression) than would stocking pure northerns or Flas. There are 2 genetic concepts involved. Outbreeding depression (crossing separate species which can lead to hybrid vigor followed by reduction in fitness in Fx generations) and inbreeding (genetic regression from continued reproduction from too small a related population leading to reduced fitness). One is from too diverse a gene set from 2 species when crossed over time and the other from too small of a gene set from related individuals. Any population of LMB , whether Fla ,Nort or intergrades in limited numbers ( fish from a small set of brood fish) in a closed environment will be subject to less fitness over time from inbreeding. That is not the reason nor question here involved as type of LMB has no bearing on that. A bunch of Northern LMB in that circumstance is just as likely as F-1s to exhibit the inbreeding problem. The fix on this problem is easy - remove some LMB and replace them with fish from another set of brood fish (add new genes) from a similar location. The second problem , outbreeding depression, is what was suggested in BM's post. In the article below , which is by some of the same cited writers, genetic testing over the entire US LMB population (90 locations) showed higher gene diversity in intergrades than in Fla or Norts. This same mix of intergrade genes is the naturally occurring gene mix in the intergrade locations. See map below. As such it is the set of genes best adapted for that location (intergrade zone). I suggest that stocking intergrade genetics into the intergrade zone is less likely to result in outbreeding depression than would stocking pure Flas or pure Norths because they are the best adapted genes for that location. This is consistent with these writers premise that you should not stock genes from one population into a separate different population because the mixing with non-native genes will be more apt to result in outbreeding depression. As per the article cited in BM's post " This kind of population mixing (termed stock transfer) potentially affects the fitness of the recipient population deleteriously as a result of outbreeding depression. Outbreeding depression is the reduction in fitness in the progeny of two parents that were too distantly related to each other. " In LMB terms this would mean parents from for example from different geographic regions not parents (whether Fla or northern) from the same location (the intergrad zone). More later.



A Biochemical Genetic Evaluation of the Northern and

Florida Subspecies of Largemouth Bass 1

DAVID P. PHILIPP

WILLIAM F. CHILDERS

GREGORY S. WnXTT







We also have calculated for each population

the mean number of alldes present per locus,

the percentage of loci which were polymorphic,

and the mean observed and expected heterozygosity

(Table 1). The lowest levels of allelic

polymorphism were observed in the populations

of the pure northern subspecies (1.09 allele

per locus; 8.3% polymorphic loci; observed

mean heterozygosity of 0.024). Pure Florida

largemouth bass populations were considerably

more polymorphic (1.14 allde per locus; 11.0%

polymorphic loci; mean heterozygosity of 0.041),

but the intergrade populations were, as expected,

the most polymorphic (1.22 allde per

locus, 15.5% polymorphic loci; heterozygosity

of 0.051). These represent statistically significant

differences between groups. The observed

heterozygosity levels for the two pure subspecies

were somewhat lower than that reported

for teleosts in general: 0.051 by Nevo (1978)

and 0.048 by Winans (1980). The intergrade

populations, however, demonstrated a mean

heterozygosity consistent with these values

(0.051). It remains to be determined if the

higher heterozygosity in the intergrade zone,

relative to the pure subspecies, is a consequence

of heterosis. However, that maximal heterogeneity

is located in intergrade populations may

help to explain, in part, the existence of a "bigbass

belt" in northern Florida and southern Alabama

and Georgia, as well as the largemouth

bass of "trophy" size being taken from certain

lakes in Texas and California.

In any case, the intergrade zone today must

be considered to consist of northern Florida, as

well as at least substantial portions of the states

of Mississippi, Alabama, Georgia, South Carolina,

North Carolina, Virginia, and Maryland.

The extent of influence of some of the genes

characteristic of the Florida subspecies in certain

more peripheral states within the intergrade

zone, particularly those of Mississippi,

Maryland, Virginia, and North Carolina is uncertain.

Some bodies of water in these states still

may contain populations of pure northern

largemouth bass. The presence of Florida alldes

in populations in Texas, California, Arkansas,

Illinois, and perhaps Louisiana, probably

are the result of deliberate introductions.

Further investigation to determine the status of

numerous populations throughout several states

is required to delineate the true extent of the

intergrade zone. Once genetic differences between

populations are better understood, and

once we understand the roles that short-term

and long-term fitness play in determining the

range and distribution of phenotypes, we will

be in a better position to design effective management

programs.



In addition, populations within each group

(northern subspecies, Florida subspecies, and

intergrades) were compared and the groups as

a whole were all compared based on Nei's (1978)

identity coefficient, I (Table 9). Intragroup

variation was least among populations of pure

Florida subspecies (I = 0.997), intermediate

among populations of the nortfiern subspecies

(I = 0.992) and greatest among the intergrade

populations (I = 0.972). The intergrade populations

were approximately as closely related

to populations of the pure Florida subspecies

(I = 0.960) as to populations of the pure northern

subspecies (I = 0.962). Finally, as expected,

the two most distantly related groups were the

two pure subspecies (I = 0.911).



In an environment with high thermal variability,

the long-term success of stocked largemouth

bass might be greatest for cohorts with

the highest levels of genetic variability. However,

the two subspecies have evolved quite different

tfiermal requirements (Hart 1952; Latta

1977; Cichra et al. 1981), and it would be unrealistic

to expect those fish in the intergrade

zone, those fish with the higfiest genetic variability,

to be well suited for either an extreme

northerly or southerly environment. Introduction

of Florida alleles into northern populations

of largemouth bass could lower tfie overall fitness

of these populations under the normally

lower temperatures encountered by the northern

subspecies. A similar but reverse situation

may result from the introduction of northern

alleles into populations of Florida largemouth

bass

Ewest like alwyas thanks for well written explanation.

It's pronounced just like you spell it. :P

More info. In this study admix is a fish with both Nort and Fla geenes (an intergrade an F-1 is also an intergrade)
Admixture Analysis of Florida Largemouth Bass and

Northern Largemouth Bass using Microsatellite Loci

DIJAR J. LUTZ-CARRILLO*

CHRIS C. NICE, TIMOTHY H. BONNER, AND MICHAEL R. J. FORSTN

LORAINE T. FRIES



Transactions of the American Fisheries Society 135:779–791, 2006


Copyright by the American Fisheries Society 2006



We found no evidence of a heterotic effect (in terms

of size) resulting from first-generation crosses between

Florida largemouth bass and northern largemouth bass.

The majority of trophy-sized fish with an admixed

genome were later-generation hybrids with a larger

percentage of Florida largemouth bass alleles. There

was also no observable negative impact on size from

the admixed genetic background in these fish, most

likely because of the modified environment to which

they were introduced and the nonadaptive radiation of

micropterids (Near et al. 2003).

So...it looks like I'm good to go; with F1 bass and CNBG + BG.

Ewest is my main, main man.

thank you.

What is the latest on this subject ewest? Any final answers?

Would this subject be along the lines of meanmouth bass?

I was wondering what some spotted bass mixed in with a population of LMB would do.

Thought this might be of interest if anyone is still following this thread...

http://www.activistangler.com/journal/20...ntersville.html

Work is still ongoing, but would be glad to answer questions about our findings with backcrossed, introgressed bass, F1s etc if there's interest.

What do you take as a sample to determine DNA?

We use a fin clip (about size of men's dress shirt button).

Thanks!

Sorry one more question: how long does it take to get the DNA information?

No problem. Usually about 2.5 weeks..

The actual process takes about 2 days, but we usually process the samples in batches, so there is some delay to allow for enough samples to go forward with a run.
More details at:
http://peatmanlab.org/services/