Borelli Thesis

[Travis Dahl KE4VYZ <dahlt@umich.edu>]

>
>    You know, when I looked at that paper, I did notice their were some
> temp/pH combinations that seemed underrepresented and I wondered about the
> statistical significance too...
>    A few thoughts:
>    First off, I'm really jealous.  Someday I'll have enough time/space/$$ to
> do something like this. <sigh>
>    There may only be one or two broods per temp/pH combo, but each of those
> broods may have been sizable...Which does leave you open for the possibility
> of correlations within the brood (i.e. genetic predisposition based on a
> given set of parents, etc.)
>    Jonathon, when you get your data, I would suggest using a two-way ANOVA
> (as probably will anyway)  to test for interaction effects (i.e.  Temperature
> has an effect and pH has an effect, but so does the _combination_ of pH and
> Temperature)
>    As always (and I can say this because of my strong statistics background),
> statistics can't actually "prove" anything, but they're about the best tool
> we have.
>    Sorry if this rambled a bit or anyone was brought to tears because of the
> references to statistics. <grin>  Good luck and keep us informed of how
> you're project's going.
>
>>
>> Date: Thu, 14 Dec 2000 14:37:22 -0700
>> From: Mike & Diane Wise <apistowise@bewellnet.com>
>> Subject: Re: 
>>
>> Jonathan,
>>
>> I rechecked the reference and you are correct. It shows 17 spawnings. I also
>> have their
>> preliminary report (Römer & Beisenherz. 1995. Modifikatotrische
>> Geschlechtsbestimmung
>> durch Temperatur und pH-Wert bei Buntbarschen der Gattung Apistogramma in
>> Symposiumband: Fortpflanzungsbiologie der Aquarienfische, Birgit Schmettkamp
>> Verlag,
>> Bornheim.). In it they used 21 spawns, or about 1500 fry, with tight
>> controls (no
>> spawns with losses over 10% and extremely precise controls on pH,
>> conductivity, &
>> temperature). I assume the reason they used acid water conditions was
>> because apistos
>> prefer breeding in acid water. Spawns in basic water tend to lose
>> significant numbers
>> of fry. The eggs are laid but they often don't hatch in large numbers. I
>> don't know,
>> but this may explain why they have no spawns listed for basic water
>> conditions. None
>> met the 90%+ survival requirement. I am not a statistician so I can't
>> comment on that
>> part of the paper or why they considered the number of broods sufficient for
>> statistical studies.
>>
>> I, for one, would be very interested in learning your results. Will you be
>> maintaining
>> consistent conditions from spawning to sexing? If Römer & Beisenherz are
>> correct, any
>> changes in conditions will change the final results. Please, let me know
>> your findings
>> when you finish your thesis. They will be valuable evidence to confirm or
>> deny Römer &
>> Beisenherz's studies.
>



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