Long term maintenance of a wild strain?

I recently acquired four pairs of wild Brazilian Guppies which I am delighted with, they are soon ready to leave quarantine and have already released a few young.

This has made me think about long term maintenance of these fish mainly due to their rate of reproduction.
There is basically no option when it comes to introducing new blood from the wild as there is next to no chance that newly imported fish would come from the same locality as this import, or even the same country for that matter.

As its only eight fish they will represent the only a fraction of the original strain but I can’t do much about that.

Optimally someone here on the forum got fish from the same strain and fish could be swapped in the future but I would like to hear views on basic maintenance apart from this.

Thoughts:
* Keeping the fish together and let everyone breed with everyone, sort of hope for the best approach. A potential problem here could be that one particular male is more popular than the others, inbreeding and also that there is no backup if something goes wrong.

* Divide them into four pairs in separate tanks and after a year or so swap say all females from one group with the females from another group. This is what I am considering right now.


* Somewhere in between the two above.

I do not have the interest or the space to keep track on each batch and each individual nor would I be interested in deciding exactly who breeds with whom. I suppose I am looking for a simple solution, I would also like to keep the fish in large groups without too much interference from me.

If it would have been a slower growing/reproducing species I would have been more inclined to keep records of each fish.

What are your thoughts on this, and how long could you keep a healthy strain going with just a small starting group and what is the best approach? Ideally I would like to keep this as a healthy strain “forever”, is this possible without new blood?

I'm aware that these fish will be fine for many generations but I would like to do it right from the beginning instead of looking back 5-10 years from now wishing that i would have gone down another route.

Andreas

It is the selective pressures that the wilds place upon a line that cannot be mimiced so easily in captivity that may make all the difference.

In opinion and experience, placing pressure on the genes that comes close to that experienced in nature (but not necessarily mimiced) produces the best offspring. If the wild type genetics are dominant then that will, thus, tend to favour maintenance of the wild strain.

If the offspring are wrapped in cotton wool then you are more likely to see an increase in less fit specimens.

ian

igmillichip wrote:

It is the selective pressures that the wilds place upon a line that cannot be mimiced so easily in captivity that may make all the difference.

In opinion and experience, placing pressure on the genes that comes close to that experienced in nature (but not necessarily mimiced) produces the best offspring. If the wild type genetics are dominant then that will, thus, tend to favour maintenance of the wild strain.

If the offspring are wrapped in cotton wool then you are more likely to see an increase in less fit specimens.

ian

Thank you for the response Ian.

How do we place pressure on the genes in the home aquaria in practice? Are we talking about predation and competition for instance?

Andreas

Melander wrote:

igmillichip wrote:

It is the selective pressures that the wilds place upon a line that cannot be mimiced so easily in captivity that may make all the difference.

In opinion and experience, placing pressure on the genes that comes close to that experienced in nature (but not necessarily mimiced) produces the best offspring. If the wild type genetics are dominant then that will, thus, tend to favour maintenance of the wild strain.

If the offspring are wrapped in cotton wool then you are more likely to see an increase in less fit specimens.

ian

Thank you for the response Ian.

How do we place pressure on the genes in the home aquaria in practice? Are we talking about predation and competition for instance?

Andreas

Certainly competition is the key......buyt it does have to be the right competition.

What might seem like "competition" to us might not be competition to the fish.

The basic principles of Darwin's "survival of the fitness" has been mis-interpreted so many times: fitness to the species in question may be the inability to fly or lack of legs or the strongest legs.

An aquarium may place too much of an artificial pressure on the offspring......but there has to be some form of pressure if you don't want to produce a declining gene pool.

You may have to step in and remove the odd sport/mutant that you spot (but you won't spot all mutants as not all are easily identifiable phenotypes).

Basically, for this project, you let it start and don't over pamper the fish. Select out those that are clearly not fitting.
That is really the best you can do.

ian

Culling muts is something I do with other fish and intend to do with these too and I do plan to keep them in larger numbers which should increase the competition so that is good news.

A future issue with these compared with many other fish is the difficulty in acquiring new blood.
What is your opinion on keeping several lines going at the same time created from the original eight? The thought was that all the original WC individuals get a chance to reproduce and that these lines can be crossed in the future. Is this a good starting point or is there a better way?

Thanks again,

Andreas

Given the difficulty in acquiring future WC stock from the appropriate locale, then you are gonna have to work with the lines from the original group.

You are eventually going to get in-breeding at some stage. There would be a question as to how far does a line go before in-breeding is not occurring.

In-breeding does not cause genetic problems/mutations.
In-breeding will, however, increase the chance of any genetic problems coming to the fore.

Some species of animal will be sexually repealed by those having similar immune systems (MHC systems to be more precise).....that could be interpreted as an in-built system to minimise breeding between individuals of close genetic makeup (eg close relatives).
So that is something that could be a limiting factor [nature has many ways to increase genetic diversity].

There is, of course, one fundamental problem to overcome in all of this.......does nature want static consistent genotypes ? By the seems of things.....that is something nature will work against [eg the "perfect " genetic structure may be a hazardous liability to future evolution]

ian

Some species of animal will be sexually repealed by those having similar immune systems (MHC systems to be more precise).....that could be interpreted as an in-built system to minimise breeding between individuals of close genetic makeup (eg close relatives).

That goes for your partner too.
How many times have you both been ill at the same time ?

Thanks for the input, I think I will get this started then.

I hope to take some photos of the original individuals, It could be interesting to compare them to their future offspring down the line.

Andreas

Hi Andreas - I got a few pairs of these as well - and as with yours, I already have some young.

If you like - we can swap some offsrping in a few generations to do an out-cross and see if it helps maintain the diversity!

Jim wrote:

Hi Andreas - I got a few pairs of these as well - and as with yours, I already have some young.

If you like - we can swap some offsrping in a few generations to do an out-cross and see if it helps maintain the diversity!

Good stuff Jim, I'm definently up for swapping some future guppy offspring. If we both keep them for the long run we could even do it once every year or two.

Andreas