Re: NANFA-- Bluenose shiner news

Steffen Hellner (
Mon, 22 Sep 2003 11:54:10 +0200

> Von: Jay DeLong <>
> Antworten an:
> Datum: Sun, 21 Sep 2003 12:14:15 -0700
> An:
> Betreff: Re: NANFA-- Bluenose shiner news
> At 08:31 PM 9/21/2003 +0200, you wrote:
>> I see one mayor difference to what I mean in your example of the salmons.
>> Re-introducing a species to its former range or habitat is a lot different
>> from trying to introduce a species into the range of another one which is
>> its sibbling ecologically. This is comparing apples and cherries.
> I agree. But you started it :-) I was going off your citing introduced
> exotics as some evidence of something inherent in all fish.

Well, think we have some different points of view. Pure genetics is too
mechanistic in my mind. Genes and allels can and do vary and change out of a
the range of mesuring and prediction. Ther is something above the mechanism
which makes it felxible, variable, unpredictable.

>> Genetics is a great field. But the genes are only the playground and toys
>> for nature. The game however makes it! ;-)
> What genetics offers is the only objective way to understand such a
> topic. It's the evidence and the data and the language.

I very much doubt that we will ever really understand it. Why e.g. are
clones in many cases not viable though they should be from the mechanistic
approach? What about the cleptones in greenfrogs where species steel genetic
information from other species (Rana ridibunda-esculenta-lessonae -

>> If the "rare" genes were that important for nature,
>> they wouldn4t be that rare and we would only have a handfull of species
>> compared to the diversity we really find.
> Animals aren't like Fords off the assembly line. It's the rare unexpressed
> genes that hold the keys to survival in response to environmental changes,
> and it's the total amount of genetic information contained within the
> population-- not an individual-- that defines a species.

Very right! That is what makes genetics so week - it4s always expressed as
the whole but comes from a very limited number of studied specimen.;-) Of
course it always is the population resp. species as a whole that matters.
But the process of splitting of species is poorly known. How long does it
take and how does it start? There are species highly endemic with very small
population basis, e.g. some vipers of the genus Bothrops in Brazil, some of
which already extinct, which live or lived on tiny islands, were highly
inbred and are about to collaps by natural causes. Other species are based
on extremely little numbers for a long time and obviously do well by this.
E.g. many cave dwellers like Typhlomolge rathbuni or its european
counterpart the "Grottenolm". Obviously not all species need the rare genes,
most probably because their habitat offers stable conditions. But even
species which are more generalistic do thrive on a very reduced genetec
basis/variety, I think of the pilgrim falcon (Falco peregrinus) or the white
antilope from Saudi-Arabia. Can genetics tell us, why?

The Aquatic Conservation Network (when still around) had
guidelines/protocols for
> maintaining genetic diversity in a captive rearing program. Any such
> program would have to start with that. But no program is a remotely close
> substitute for conserving the species in the wild in its natural
> habitat. The health of a species is a reflection on the health of its
> ecosystem. Ecosystem health and species diversity, not how many
> individuals of one single species are there, are what were left us by
> Nature and previous human caretakers (good or bad), and what become our own
> legacy.

I absolutely agree. A wide genetic basis for backup populations but first of
all conserving the biotopes/environment. But if a species is lost in the
wild, I rather prefer it still present in captivity on what genetic basis
ever. And if it becomes 99% homocygote - what the heck, the phenotype is
there. Of course the natural way of species development will have ended then
but it ended for more species already than actually live on our planet. They
come and go natuirally. Our task is not to disturb this process more than
unavoidable. The Panda will go naturally, the rinocerosse as well by natural
process, we only accellerate it. These species ar not that important for the
natural progress at an overall scale. Much more important are the widely
spread modern species which still have potentials to develope. Nobody would
let a 99 year old man nominate for olympic games as long as there are 22
year old ones. Even species have their time and when its over its over. Thsi
has to be accepted. What has not to be accepted is extinction caused by
human efforts.

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