Bruce didn't quite send out all of our discussion, so here it is in
one chunk with trivial verbose removed. We are interested to hear what
people have to say about our various comments and to see if there is much
of a consensus.
<Hansen>
Made some comment as to how to minimise inbreeding / loss of genetic
diversity in aquarium stocks of rainbowfish, in terms of what should we
be doing to maintain genetic diversity and good fish.
<Unmack>
> > I don't know if that would be very useful. How many folks would be
> > prepared to swap fish with other folks? I'd always hear "my fish were
> > better than that other blokes" I suspect. Plus, you would have to swap
> > sexes, not pairs to make much difference. The main thing you can do is
> > slow down the genertation time. Plus, with such a small gene pool to
> > start with it probably won't make that much difference for NG fish. And
> > also, the question is why worry to any great extreme? The fish seem to
> > be doing ok with the present level of inbreeding, thus does it really
> > matter?
> > On a more positive note, :-)
> > I think that if folks used a group of fish to breed from (like you've
> > been suggesting for years), slowed their generation times down to
> > every 2.5-4 years, and added a couple of either sex every 2nd or third
> > generation that would be more than adequate and reasonably achievable for
> > aquarists to maximise genetic diversity.
<Hansen>
> I agree that it is more practicable as long as we can keep an eye on how
> they are going for visible phenotype ( God knows how they will be going
> biochemically and geneticaly) and keep pushing the wild type as the model
> ;-)
<Unmack>
> > I think the more interesting
> > issue is the effect of environment on phenotype relative to genetic
> > effects. I doubt it would be too hard to demonstrate that most
> > deformities we see are not genetic
<Hansen>
> A couple of times I have used misshapen breeders in the past when I was all
> keen on the effects of Vitamin C, D and so on, and the effects of stale
> food, storage techniques and so on but I cheated in the end by deciding it
> was too difficult to estimate what was hapening to the food and it had all
> been done before. In the end I just raised my future breeders ouside in a
> pond with good food supplemented with the natural insects and fry and at
> the end of the season brought them inside for the winter selected my future
> breeders and put them in another tank and kept on breeding with the old
> ones as long as I could.
<Hansen>
> I think the whole genetics/deformity and environment/deformity thing has
> been made too complex and lends itself to the "guru syndrome".
<Unmack>
I dunno, I thought it was pretty simple myself. What's so complex about
it?
<Hansen>
> We stick the
> poor blood fish in a pokey little tank give them a fraction of the
> comlexity of environmental requirements that they have evolved to need, no
> matter how adaptable they are, and wonder why they don't turn out "right".
<Unmack>
I don't think it is as detailed as that. I doubt many of them have the
"comlexity of environmental requirements." I think it is more a matter
of providing clean water and a good diet.
Cheers
Peter Unmack & Bruce Hansen