# culling



## Otis (Apr 16, 2006)

I don't get it. So basically you kill a frog becuase you think it's natural? I don't know enough about it to say a whole lot, but I do know that _humans_ killing an animal is not natural. at least IMO. if anyone could shed some light on the situation.


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## xm41907 (Nov 26, 2007)

in what regard are you referring to culling? Are there any breeders out there culling their populations? I could only see this happening if there was an outbreak of an infectious disease, and isn't considered culling.


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## stevemc (Aug 13, 2007)

I have not heard of this either. Where did you hear of culling?


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## thong_monster (May 6, 2006)

Talking about frogs with SLS?


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## xm41907 (Nov 26, 2007)

hmm, I've never heard of culling in this regard before. I've always heard culling in terms of population reduction for the benefit of the whole. ie. killing off the weak so there will be enough food for the rest. Some people use culling as a reason for game hunting. 

In terms of frogs, I guess if you are a breeder, you would want to remove individuals with deleterious characteristics from the breeding population. if you did not kill/destroy these rejects, is it still considered culling?

James


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## Otis (Apr 16, 2006)

i don't really consider killing frogs with sls culling. i think it would be more cruel to let it slowly wither away into nothing. 

i think of culling more as random, like when people are trying to stimulate the most natural conditions possible. i am talking about culling in regards to darts in captivity. say, if someone had enough food/recources ect. and there is 2 weak frogs and 5 strong ones. do they just draw from a hat which one would be culled? healthy frogs get killed in the wild too, it's how healthy a frog is, but also luck. again, don't really know what i'm talking about, anybody had personal experience with this? 

could you just give the frog to somebody else? is culling the weeding out of random frogs by killing, or by any means like just removing them from the tank and giving them to somebody else? 

i was just thinking and there was something on frognet about this and so i thought i would ask here and hear what people had to say.


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## elmoisfive (Dec 31, 2004)

Culling is an important aspect of maintaining strong frog populations. The lack of culling has been cited as a potential cause for the number of substandard frogs seen in the hobby. See the following thread...

http://www.dendroboard.com/phpBB2/viewtopic.php?t=18088

I routinely cull frogs that I've produced that I deem to have issues. Culling breeding populations of any captive bred animal is simply a good husbandry practice.

Bill


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## stevemc (Aug 13, 2007)

Good point. I read the link, and an honest breeder wouldnt sell a runt or a muted color frog, he should take it out of circulation, by either just using it for a display animal and not breeding it, or some other way of not getting it into the gene pool. I dont know about killing it. I agree about feeding and care problems causing runts and bad colors. Darts need good housekeeping, and a varied diet with good nutrition, that often is not given. I would kill a deformed frog, but I am not sure about a smaller or muted color frog. But I sure wouldnt sell it or breed it again.


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## rozdaboff (Feb 27, 2005)

stevemc said:


> Good point. I read the link, and an honest breeder wouldnt sell a runt or a muted color frog, he should take it out of circulation, by either just using it for a display animal and not breeding it, or some other way of not getting it into the gene pool. I dont know about killing it. I agree about feeding and care problems causing runts and bad colors. Darts need good housekeeping, and a varied diet with good nutrition, that often is not given. I would kill a deformed frog, but I am not sure about a smaller or muted color frog. But I sure wouldnt sell it or breed it again.


I believe that Brent posted regarding the culling/pulling of "less than optimal" frogs from breeding programs at some point. But - this results in _artificial selection_. By doing so, you may be eliminating important genetic variability. Here is an excerpt from the ASN Steward Handbook:



ASN Handbook (page 37-38 ) said:


> This selection can take the form of positive selection where animals exhibiting desirable traits, are purposely chosen as breeding stock, or negative selection where animals exhibiting undesirable traits, are culled from the population and denied the opportunity to contribute genes to subsequent generations. There is a strong desire among many captive breeders to “improve” the genetic fitness of the population by eliminating apparently deleterious traits and choosing only the most “fit” or robust individuals as breeding stock. However, such selection, no matter how pure the motives, is not desirable for maintaining the characteristics of wild populations. Positive selection for desirable traits is the equivalent of selective breeding which can drastically alter the phenotypic and genetic characteristics of a population from their wild ancestors. Likewise, although it may seem counterintuitive, negative selection to eliminate deleterious traits is dangerous or will end up reducing the overall fitness of the population. There are a number of reasons for this. For example, deleterious traits may be context specific where the trait is deleterious under one set of conditions but becomes advantageous under another. Further, it is often impossible to determine whether an exhibited trait is the result of husbandry, so elimination of deleterious traits may actually select for a population adapted to substandard husbandry practices. Another problem is that the elimination of a deleterious allele could result in the loss of a number of other alleles (and therefore loss of genetic diversity) due to genetic linkage. For a more detailed discussion of this topic, see Lacy (2000).


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## elmoisfive (Dec 31, 2004)

Agreed that is a possibility. Given the number of substandard frogs I've seen floating around at shows, my concerns about the direction of the hobby goes beyond the theoretical to the immediate reality.

By the way I think that anyone who culls a frog for its coloration is an idiot....but for a frog that is showing clear developmental abnormalities? Different situation.

Bill


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## Otis (Apr 16, 2006)

thanks for the replies, i sort of get it now. i completely understand that the weaker frogs have to be culled, but what about the healthy ones that are just randomly selected? and by limiting the gene pool to those frogs we deem the most desirable arn't we in a way selective breeding? i don't so much mind this idea for leos and stuff, but for darts it doesn't seem right. arn't most people trying to keep the wild genetics within cb frogs? eventually, in theory, if we stop taking frogs out of the wild (not saying we should), wouldn't the "wild genetics" go way way down, even though the original frogs were wild of course?


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## xm41907 (Nov 26, 2007)

otis07 said:


> i completely understand that the weaker frogs have to be culled, but what about the healthy ones that are just randomly selected? and by limiting the gene pool to those frogs we deem the most desirable arn't we in a way selective breeding?


What do you mean about the healthy ones? Yes it is selective breeding. 




otis07 said:


> i don't so much mind this idea for leos and stuff, but for darts it doesn't seem right.


Why isn't it right?



otis07 said:


> arn't most people trying to keep the wild genetics within cb frogs? eventually, in theory, if we stop taking frogs out of the wild (not saying we should), wouldn't the "wild genetics" go way way down, even though the original frogs were wild of course?


there isn't something tangible called wild genetics. basically what people mean when the say wild genes is the genetic material of a wild population. when a wild population is captured for breeding, the genetic variability becomes limited to only those that have been collected. subsequent generations genetic variability are decrease due to interbreeding within this population. and geneticly "bad" traits, that might cause a frog in the wild to perish could remain in the population. This is why inbreeding can cause so many problems. 

adding fresh genetic material (collecting new frogs and introducing them into the breeding population) increases the genetic variability in the captive populations. more variability = good. less variability = bad.


I'm not sure if I explained it this well enough, anyone else with a genetics background want to help explain it??

James


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## MonarchzMan (Oct 23, 2006)

I don't think that culling is like Russian roulette in that you just pick a random frog to cull. Were it me, I would cull frogs that had issues, but wouldn't even bother with perfectly healthy frogs.


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## bbrock (May 20, 2004)

elmoisfive said:


> Agreed that is a possibility. Given the number of substandard frogs I've seen floating around at shows, my concerns about the direction of the hobby goes beyond the theoretical to the immediate reality.


I just posted a link to a cool article about culling on an SLS thread in the medicine board yesterday (it's also referenced in the ASN handbook). But it really depends on the goals as to what constitutes proper culling. Anyone want to lay odds on how many of those substandard frogs at shows are the result of bad husbandry rather than genetics? Culling won't do a dang thing to create bad husbandry, all it does is artificially select animals that can thrive under neglect. And that is not an entirely bad thing if our goal is to create populations of frogs that thrive under the typical environments we provide. But if we our goal is to keep the animals as much like they are in the wild as possible, then such culling may not be wise.

Edit: whoops, that article is posted in the breeding section, here's the link to the link: http://www.dendroboard.com/phpBB2/viewt ... c&start=13


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## Catfur (Oct 5, 2004)

Couldn't a lack of culling allow specimens which would have little to no chance in the wild to survive, thus adding their less fit genes to the gene pool in a frequency out of proportion to what they would in the wild?


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## bbrock (May 20, 2004)

Catfur said:


> Couldn't a lack of culling allow specimens which would have little to no chance in the wild to survive, thus adding their less fit genes to the gene pool in a frequency out of proportion to what they would in the wild?


Sure, but it could also remove animals that would have a GREATER chance of survival in the wild but just doesn't do well under our captive conditions. What we can be pretty certain of is that such culling will select traits that do well under our husbandry conditions. And that may be a good thing depending on our objectives.


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## Ed (Sep 19, 2004)

With respect to the idea of substandard frogs.... especially the idea of runts... 

People need to keep in mind that we are optimizing the maximal growth of the frogs by feeding the levels we do... This will cause froglets that are slower in growth for any reason (competition, smaller size at metamorphosis etc) end up appearing "runty" when compared to faster growing siblings even though the frog maybe well within the size of the natural populations. 
This phenomena can often also be seen when people post pictures of "thin" frogs... 
In Zoo breeding programs, animals with known deleterious traits (such as diabtes) but underrepresented genes maybe bred back into the population as the health issue maybe due to husbandry issues... .

Ed


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## Rain_Frog (Apr 27, 2004)

I have mixed feelings about this topic.

I agree that culling must be done (I do it), but it is difficult to access which animals should be culled, because I do not know exactly what the natural habitat eliminates.

Yes, I agree that selecting animals that will mature faster is not always a good idea. However, it is not easy to access either if the larger animals are just larger because they are either healthier or genetically growing faster. Therefore, the only standard I go by (as far as tadpoles) is to keep larger, more aggressive ones and eliminate the ones that are only half the size.


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## bbrock (May 20, 2004)

Rain_Frog said:


> I have mixed feelings about this topic.


Then you obviously get it. You should have mixed feelings. I'm not even convinced it "should" be done. As I've said, it depends on the goals of the breeding program. Okay, if an animal is suffering, yes, it should be culled. But I get a very queazy feeling when people start culling "substandard" animals. Where can I find this standard? Who defines it? It is all just a little too AKC for me. Can we say, eugenics?


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## xm41907 (Nov 26, 2007)

culling for desirable traits in viv is understandable. I highly doubt any respectable breeder would even consider releasing captive breed frogs into the wild, therefore selective breeding for the intention of enhancing frog traits for captivity remains appropriate. When considering the options in culling, I would assume that this is done at an early age, rather than with mature individuals. While the destruction of a frog is never easy, in some instances it is justifiable. 

James


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## Conman3880 (Jul 8, 2007)

xm41907 said:


> ...culling for desirable traits in viv is understandable. I highly doubt any respectable breeder would even consider releasing captive breed frogs into the wild...


Then why is hybridizing so bad?

I'm not a conservationist, but I thought one of the reasons people raise darts is to protect the species. Maybe I'm misunderstanding the concept, though.


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## xm41907 (Nov 26, 2007)

one way to think about hybridizing is to think of the reverse of what happened with mans domestication of dogs. We started with one "wild type" and through the centuries have selectively breed for differing traits. Some lineages went towards smaller traits (think Chihuahua), while some went towards larger traits (think Great Dane). the genetic variability was there through the wild type, and we selected for specialized traits to come out with however many breeds of dogs now.


With frogs, we won't to maintain the wild type traits from each population. By this I am referring to different species and their varying morphs. Just because you can make a cross between two different morphs and create something unique, doesn't mean it should be done. Breeders in this hobby want to remain true to the original morphs as possible. I don't want a great dane of the froggy world, from which I don't know where it's ancestors originated specifically. I would rather take something for which I can trace back.

If hybrids became popular, it would lessen the uniqueness because there would be too many possibilities. Just look at this forum for the enthusiasm towards new morphs being brought into the trade!

James


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## bbrock (May 20, 2004)

Conman3880 said:


> xm41907 said:
> 
> 
> > ...culling for desirable traits in viv is understandable. I highly doubt any respectable breeder would even consider releasing captive breed frogs into the wild...
> ...


Well, the protecting the species argument is pretty misunderstood, overemphasized, and often used as an excuse to rationalize unethical behavior. But the hobby does seem to be genuinely interested in keeping these animals in a wild type condition which is why I like it. I agree that culling for better performing animals can be justified if you are clear about why you are doing it, but it is a form of selective breeding which really does belong in the same bin as hybridization. Whether we hybridize, selectively breed, or cull, these are all ways to manipulate genetics to suit human desires. So we have to be very careful if we say we want to keep them wild on one hand, but must cull "undesirable" animals on the other.

Okay, I've resisted mentioning wolves as long as I can but I can't resist. I often hear that wolves are good for the wild game they eat because they keep them "strong" by selecting for fast and alert animals. But the fallacy of this argument is that the only reason they NEED to be fast and allert is because the frickin' wolves are trying to kill them all the time! The point being that if we want to manage animals to make them better, we need to ask, better for whom?


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## xm41907 (Nov 26, 2007)

bbrock said:


> The point being that if we want to manage animals to make them better, we need to ask, better for whom?


You hit the hammer on the nail. This all boils down to for whom are we acting. Even if you were to touch nothing other than putting a population of an organism into confinement, provide them with what appears to be an optimum environment and food over the generations changes will occur in that population. those individuals best suited to that environment will be most fruitful. this doesn't mean all others will die out, but there will be some with traits that are at a disadvantage in this environment. given enough time, the dominant traits in this population may become unsuitable traits for their original natural habitat. 

So now the question remains, in whose best interests are we acting? My answer is: for us, the frog enthusiasts. we want frogs the we can appreciate. The fact that we want to have a frog of our own inside a cage, no matter what type it is, we are still acting in our interests. Is this necessarily bad for the frogs? No, provided we are treating them adequately. 

Overall, I have been quite impressed with people in this hobby. The majority of people I've talked with and read from show a great interest in the well being of the animals, and for the education of the hobby itself. Everyone that takes the time to contribute meaningful information on this or any other forum deserves a big pat on the back. 

Thanks!
James


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## Ed (Sep 19, 2004)

xm41907 said:


> So now the question remains, in whose best interests are we acting? My answer is: for us, the frog enthusiasts. we want frogs the we can appreciate. The fact that we want to have a frog of our own inside a cage, no matter what type it is, we are still acting in our interests. Is this necessarily bad for the frogs? No, provided we are treating them adequately.
> 
> James


And the other position to this is that if we are simply keeping the frogs for our benefit then there is a significant chance that the basic wild type frog will not be viable in the longterm. 
This has been already shown to be the case in the hobby in the last 20 years where frogs that were once common are either no longer available or have a very tiny population in the hobby which in theory could place the long term survivial of that frog in question. 

Ed


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## Otis (Apr 16, 2006)

i guess it depends on why we are keeping them? i suppose some such as zoos and conservation groups are keeping them for the frogs, but others are just keeping them because they like to have control over stuff? don't know what would make them pick darts over something easier like leopard geckos, but...?


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## elmoisfive (Dec 31, 2004)

Of course, playing devil's advocate here, the odds that we are maintaining the 'wild type' in captivity are not good. Frogs are being kept by and large in small glass boxes, cleared and kept free of pathogens, fed a diet that certainly doesn't mimic their natural fare and kept free of other environmental pressures such as predators plus other species that compete with them. The tadpoles are oftentimes raised under circumstances including diet that don't replicate their natural environment.

How these conditions influence the frog populations over time can only be speculated upon. We aren't going to be able to run the control experiment and unfortunately for many of these frogs, the wild type comparitor won't be around in the future.

Bill


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## bbrock (May 20, 2004)

First a reply to Bill. There are tools that allow us to do a pretty good job of retaining wild type traits. But first we have to let loose of the idea that the only way to retain those traits is to mimic natural selection in captivity. To the contrary, those wild traits are stored in genetic alleles. And by managing the captive population such that all alleles get passed to subsequent generations in about the same proportions they are found in the wild population, we can maintain those wild traits for many, many, generations. It's a simple matter of coordinated management and probability really. A great deal of research in conservation biology supports it.

Second, I propose an excercise. Next time you are bopping around your local marsh or pond, try to capture as many frogs as you can to examine. And each time you pick up a frog, ask yourself if you would have culled that animal had it shown up in your collection. The fact of the matter is there are a lot of crappy looking frogs bopping around in the wild that are apparently unaware that they should be culled to make the species more fit.


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## elmoisfive (Dec 31, 2004)

However, conditions change over time. Today your average dart frog in the wild has to contend with deforestation, chytrid and climate change. That is their true 'natural environment' albeit one that has altered dramatically on a timescale that is not conducive to adaptation via genetic mutation.

As I said, I'm playing devil's advocate here. Within 50 years or perhaps 100, we are likely to see a scenario where few or perhaps none of these animals exist in the wild. Not something I'm happy about but I have to be a realist. 

Yes the information is contained within their genetic code but that code is highly malleable and under multiple influences. Extrapolating from past information could be informative or it could be misleading. The datatset is too small to be definative. All I'm saying is that one can't be sanguine about success regardless of best intentions. 

Bill

Bill


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## Ed (Sep 19, 2004)

elmoisfive said:


> However, conditions change over time. Today your average dart frog in the wild has to contend with deforestation, chytrid and climate change. That is their true 'natural environment' albeit one that has altered dramatically on a timescale that is not conducive to adaptation via genetic mutation.


Yes conditions change over time but the genetic plasticity you referred to below is what allows the animal to adapt to these changes in the wild and if we do not attempt to preserve the original data set then we are automatically reducing the fitness of the animals. 




elmoisfive said:


> Yes the information is contained within their genetic code but that code is highly malleable and under multiple influences. Extrapolating from past information could be informative or it could be misleading. The datatset is too small to be definative. All I'm saying is that one can't be sanguine about success regardless of best intentions.
> 
> Bill


However at this moment until we get the definitive genetic analysis of the frog populations in captivity and the wild, we can utilize the programs that were developed to maximize the maintenance of the allele frequency in captivity as in the wild. This is what the Zoos are doing.. its a matter of statistics depending on the starting population number... 
This is where TWI comes into play as we have access to some of the same programs to track populations and relatedness used by the Zoos and it appears to be working well for the submitted animals. 

Ed


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## elmoisfive (Dec 31, 2004)

I suppose this circular debate could go on for another 10 pages if we so desired. The concept that I object to is one that a captive bred population can be maintained to the point that it is 100% identical to the original wild type population. Now if one were to say that we are attempting to maintain them in a state approximating wild type or near wild type, I can concur.

It's the difference betweeen precision and accuracy. 

Bill


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## Dangerously (Dec 19, 2007)

elmoisfive said:


> I suppose this circular debate could go on for another 10 pages if we so desired. The concept that I object to is one that a captive bred population can be maintained to the point that it is 100% identical to the original wild type population. Now if one were to say that we are attempting to maintain them in a state approximating wild type or near wild type, I can concur.
> 
> It's the difference betweeen precision and accuracy.
> 
> Bill


Exactly. We aren't maintaining them in a wild state. We're trying to maintain stong, genetically viable & diverse, healthy animals for a captive ("pet" in this case) population. Therefore handling deformed animals has to be handled differently. 

Having been around the snake trade for 20+ years it still sickens me to see snakes with obvious genetic flaws sold; "I'll be ok, it's just blind in that eye, it'll still feed and breed, though". Anyone selling a boa with that obvious genetic flaw should be kicked out of the hobby (and yes, I heard that from a vendor). This does nothing for the hobby except pass along those flaws. As hard as it is to say and do, those aninals should have been placed in the freezer (euthanized) after hatching. 

All the reputable breeders cull to maintain a strong genetic pool - we should too. I know it's hard to euthanize an animal, but in the interest of the hobby and despite being tough to do, it has to be done. If you think you can't or wont do it, don't breed your animals, it's that simple.


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## Ed (Sep 19, 2004)

elmoisfive said:


> I suppose this circular debate could go on for another 10 pages if we so desired. The concept that I object to is one that a captive bred population can be maintained to the point that it is 100% identical to the original wild type population. Now if one were to say that we are attempting to maintain them in a state approximating wild type or near wild type, I can concur.
> 
> It's the difference betweeen precision and accuracy.
> 
> Bill


Bill,

How does what I (or Brent) said conflict with your idea of the difference of precision and accuracy? 

Ed


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## elmoisfive (Dec 31, 2004)

Ed,

I'll try to be brief because I have 50 more froglets to cull (j/k :twisted: ).

As you know precision and accuracy while closely related are not the same thing. For the sake of those on the board who don't know the difference, precision speaks to the reproducibility or repeatability of a result while accuracy speaks to the correctness or truthfulness of that result. For example, if an analytical instrument is miscalibrated but otherwise performing well, one can makes a series of readings that are highly precise but not accurate.

Now for our case. One can be precise in how one carries out a breeding effort but one can not be assured of accuracy. As I understand it, the argument is that if we maintain the totality of genetic diversity within a captive population (a dubious proposition to begin with given the limited founder pool in some cases) we will continue to propagate a population that reflects in totality the wild state population. 

Now within statistical variation, if one carried said breeding program out the same way in parallel and one started with sufficient genetic diversity, I accept that the outcome of those breeding efforts would be highly similar. But those outcomes may or may not reflect the desired state because I don't accept that the following assumptions are absolutely valid:

(1) Assumption that we are starting with sufficient and totally representative genetic diversity
(2) Assumption that captive bred conditions in no way influence that genetic diversity over time
(3) Assumption that the wild type population will show a parallel drift in genetic diversity despite being under a very different set of influences.

Now don't get me wrong, I fully support what TWI is attempting to do....I just don't buy the assumption that the outcome is assured. Near wild type or as close to wild type as possible under captive conditions. Sure. At least I hope so. Totally replicating wild type diversity and maintaining same? Doubtful.

Bill


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## bbrock (May 20, 2004)

Bill, I've tried to be as careful as I can to never state that I thought it is possible to exactly duplicate the wild type genome in a captive population. I have consistently used phrases like "maintaining genetic integrity that is *representative *of wild populations". That is a very important distinction and we are in agreement here full. Also, I do want to mention that Bill is one of TWI's most staunch supporters.

Also, I want to state that culling and "maintaining genetically viable and diverse populations" are counter to one another. Culling is a one-way ticket with respect to genetic diversity, and that is to *remove* genetic alleles from a population. Removing alleles reduces genetic diversity - period. You can never add genetic diversity by culling, you can only reduce it. Period.

Finally, we can look at this from two views. The first view is for maintaining the genetic integrity for captive populations so that they may retain as much evolutionary fitness for life in the wild as possible. In other words, keeping the ready for reintroduction to the wild. Well, that's kind of a silly goal for existing captive populations. The reason we push it in TWI is as a training ground so people are versed in the techniques of managing populations that really are destined for reintroduction. In other words, if you are a private keeper and you would like to participate in captive breeding for wild reintroduction programs, then you need to start managing animals more like a conservation program rather than for raising animals as pets. If you aren't interested in that, then that is fine and culling may make sense. I have never said that culling should never be done. What I have said repeatedly is that it depends on your goals. But... it does concern me that a lot of people have a poor understanding of what culling actually does - to the point they the may use culling in a way that would actually take them away from their stated goals... like maintaining genetic diversity. Culling is NOT the tool for that.

Secondly, let's just look at this from a desire to have pets that reflect the characteristics of wild animals. One of the characteristics of most wild populations is that they are variable. Oddballs appear. Sometimes you find goofy looking specimens chugging along just fine in the wild. To me, that is part of the charm and appeal of wild animals. That they don't play by our preconceived ideas of superiority. And that is my concern about culling so-called wildtype animals. If someone is making decisions about what is "strong" and what is not, then there is a danger we will lose that charm of surprise that results from a variable population. Actually, I think this has already happened with many captive populations in the hobby.


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## elmoisfive (Dec 31, 2004)

Perhaps I should have defined what I meant by culling and it could have prevented a lot of headache.

I don't as a rule, simply identify frogs and kill them on the spot. I had to do that today with an azureiventris froglet because he/she leapt out of the 190 grow up container right as the lid was closing. Needless to say it was partially crushed at the container closure and I felt the better choice was to euthanize it rather than let it suffer. Not fun stuff.

Equally what I don't do is set aside 'gimp' tanks for challenged frogs. Any froglet that can climb out of the water and isn't so obviously damaged by SLS that it won't have a chance gets to compete to live. With it's healthy siblings. Under those circumstances some of the oddballs surprise me but more often than not over time they don't fare well. To me this is a form of culling. I'm letting natural selection take place but I suspect if I isolated them in a gimp tank more might survive. But that is introducing artificial selection.

Similarly, if a froglet within a cohort starts to lag in growth compared to its tankmates, it stays with the group. Sometimes they pull through, other times they don't.

These may seem to be harsh but it's natural at one level. But otherwise I'm imposing my selection criteria on these animals and I think that's dangerous. Perhaps not the purest approach but one I can live with myself. Presumably Nature doesn't shelter the gimps though I concede that we place them in perhaps more danger due to the way they are housed.

Bill


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## bbrock (May 20, 2004)

elmoisfive said:


> These may seem to be harsh but it's natural at one level. But otherwise I'm imposing my selection criteria on these animals and I think that's dangerous. Perhaps not the purest approach but one I can live with myself. Presumably Nature doesn't shelter the gimps though I concede that we place them in perhaps more danger due to the way they are housed.
> 
> Bill


Dude, I'm way worse than you. I've gotten to a point where pretty much if a tadpole can survive to become a froglet inside a vivarium with no assistance from me at all, then it survives to become an adult. If not, it dissapears. Oh sure, I'll throw in a few fish flakes now and then if I know tads are present, but nothing more usually. Now as we get farther down the path of ASN management for some populations, I will likely change my managment style but until then, this form of selection continues.

And what you've brought up is really important. To me, culling is purposely choosing which animals live and which die. And that is not entirely unjustified IF you understand your goals and how cullling will help you reach them. Euthanizing a frog with a crushed spine could be considered culling, but is more of a mercy killing if you ask me. Where I get nervous is when people start making judgement calls about what is a suitable animal to pass to the next generation. I just want to know what criteria they are using to make these choices, and what are their goals that warrant the culling decisions.


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## Ed (Sep 19, 2004)

bbrock said:


> elmoisfive said:
> 
> 
> > And what you've brought up is really important. To me, culling is purposely choosing which animals live and which die. And that is not entirely unjustified IF you understand your goals and how cullling will help you reach them. Euthanizing a frog with a crushed spine could be considered culling, but is more of a mercy killing if you ask me. Where I get nervous is when people start making judgement calls about what is a suitable animal to pass to the next generation. I just want to know what criteria they are using to make these choices, and what are their goals that warrant the culling decisions.


I think I see where the disjunct is occuring.. 

Culling can cover the following interpretations 
1) euthanizing an animal due to quality of life issues (unable to feed, severely damaged or diseased) where the animal is going to die if otherwise left alone
2) euthanizing an animal that does not fit some standard of conformation or appearence that is either arbitrary or defined (like the AKC breed standards). This would include odd or off colors (like albinos) or "runty" animals. 
3) euthanizing an animal for population management (there is only space to keep 25 alive but you have 30 and no way to move them (unlikely but it can theoretically occur) so the surplus animals are culled. 


We have several different possibilities here that are all being mixed together which is in part causing some of the confusion (in my opinion). 

Culling is acceptable when dealing with number 1 listed above, number 2 should be avoided as much as possible and with number 3 there are possiblies that have to be reviewed on a case by case basis (for example, if you have some frogs that are unrelated to the population but you cannot rear thier offspring then if no space can be made to rear then culling may need to be considered....... 

Ed


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## valledelcauca (Apr 13, 2004)

bbrock said:


> Rain_Frog said:
> 
> 
> > I have mixed feelings about this topic.
> ...


That`s the point, one can`t imitate nature 100%, because things in nature often happen "by accident". What I want to say is that you`d have to cull healthy, "perfect" animals, too, if you`d want to do so.


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## sports_doc (Nov 15, 2004)

This should be considered for a sticky appointment. A 'Culling' sticky.

A nice discussion that even I missed until now, so before it's brought up again, a sticky it should be....IMO.

S


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## bbrock (May 20, 2004)

valledelcauca said:


> That`s the point, one can`t imitate nature 100%, because things in nature often happen "by accident". What I want to say is that you`d have to cull healthy, "perfect" animals, too, if you`d want to do so.


I think this is a point that is woefully underappreciated. Natural selections is a game of probability. But what many don't fully appreciate is that most individuals that die before reproducing in the wild are simply victims of bad luck which has nothing to do with the fitness of their genes.


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## JWerner (Feb 17, 2004)

Could the need for culling due to SLS/matchstick leg or undersized froglets be due to the fact that the parents are bred too often. Frogs are opportunistic feeders but might they also be opportunistic breeders? How many owners of their darts give their frogs seasonal changes? I have noticed four times in the year when I seem to get cases of SLS/ matchstick etc - early fall and late fall along with early spring and late spring. During the summer I break down most tanks and move frogs into their new enclosures. I mist about 50% less and provide few, if any film canisters. No broms too. Essentially, the frogs are forced to take a break. Upon fall, many film canisters are reintroduced as well as a marked increase in misting. This initial change induces breeding. I have noticed from these first clutches that cases of SLS etc. seem more likely. After that, generally I will have about 3 months of good, quality, life creating gettin it on! Through experience (vents) at about 10 - 14 weeks SLS seems to reappear. By this time though, Winter has arrived - lower temps too. I try to mist a bit less at this time too, forcing a 'seasonal break' The pattern repeats itself in spring. 
I have found that larval feeding has the greatest impact in reducing SLS/matchstick etc, while giving and increase in egg laying frequency and clutch size. I can imagine that fruit flies have much fat or protein, but the larval form I imagine must have a high level for fat and protein. Also, this is the only stage in which gut loading is possible. Dusting your flies is nice but the fries clean themselves off rather quickly and vitamins and minerals, while important, do not substitute for low fat and protein levels. The mix that you feed your larvae, IMO, is the best opportunity to supplement your frogs. Adding your vitamins/ minerals at this step is good. I have also added whey protein, spirulina and other 'additives' to my mix. 
I hope this helps a bit. I also suppose that frog age - very young and 'past prime' frogs, experience other breeding difficulties due to what their body is capable of provided to the breeding cause.


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