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Re: NFC: DP returning fish to the wild


Ahh, a lively discussion.  Before I begin, I am in no way responding to
make people mad or am I trying to prove something.  I just want some good

Thanks for the input as it has made me think a bit.  But, my premise is not
in telling people that it is OK or fine to re-release into the wild.  That
is one of the basic premises of my posts.  The second, of two premises, is
that genetic diversity is good and expanding a genetic pool, in a
"population," over time, allows for species survival.  A genetic principle
that I base this on is that a species survivability is taken over a long
period of time.  If a species color morph disappears - this is NOT bad
necessarily.  If a species resistance to a specific disease disappears -
then this is bad.  If a population receives new genes conferring genetic
resistance then this is good.  Thus, an increase in the gene pool allows
for a greater genetic diversity and a better chance for survival.  Now to
critique each response.

Josh wrote:
>Fish kept in aquaria -- or  any animal kept domestically -- are typically
inferior to the wild strains.  (Examples: Male bettas have longer fins,
they look pretty, but are no good in the wild [fins get torn, infections,
so forth.].  Goldfish, need I say more?  Cows, dogs, etc. all are bred to
either look better, or have a better traite [en gracio, milk].

-Agreed - but the re-introduced species has NOT been breed for better
looking color or fins.  The re-introduction being discussed is a native
species - not a domesticated goldfish (which, BTW, do quite well in the
wild).  Goldfish, cows, dogs, etc. have been domesticated for over
hundreds, if not thousands of years (in some cases).  Telling me that two
generations in a home tank is equal to the above mentioned time period of
forced genetic selection - I don't think so!

>Moreover, particular genetic advantages are likely to be bred out.  [e.g.,
>A fish has a particular
adaptage to avoid a given infection, or to withstand cold.  This trait is
of no use (or perhaps triggered by given factours) in the aquaria.
Therefore, in a few scarce generations, it may be eliminated.).  By
placing this fish (presumably as an adult) into the gene pool, it has a
strong chance to reproduce, and pass on the lack of gene.

-Mainly conjecture but some truth.  There is a CHANCE that the gene will be
breed out.  This does not occur in two or three successive matings.
Selective pressure occurs over long periods of time.

>Resistance to diseases is not likley to happen.  Are fish are likely to
be LESS disease resistant.  They sit in, well, the lap of luxury.  Lets
face it, compared to wild fish, they don't get sick much.

-Can you prove this - wild fish vs. tank raised fish?  Resistance occurs
because of selection.  I think that you are confusing genetic disease
resistance in the wild to genetic disease resistance in the home tank -
where we observe a cleaner environment - thus healthier fish.  This says
nothing of their genetic resistance - this happens upon encounters with
diseases and viruses.

Scott wrote:
>The issue with disease is not an increase or decrease in resistance.

-Genetically it does.  Disease exposure to a disease prone population
results in large losses of fish because they are not genetically able to
resist - they can only hope to get better.

>The problem with disease is when fish from an aquarium population have
developed immunity (resistance if you want to use that term) to diseases
that the wild populations have never encountered. When you toss the
domesticated fish in with the wild population they are exposed to
strains of bacteria and virii that they have never encountered before.
Both animals have perfectly functional immune systems but the wild one's
immune system does not know how to fight the new invader.

-Bingo.  If we are talking about the same two fish - one introduced, one of
the local area then this is good.  Other wise the population would be
destroyed.  If the two have bred (not inter breeding) then the genetics
have been passed on and the genetics of the original population have
remained - improved, of course ;-)

>This has happened before with turtles, and a couple of
years ago there was a thread about it on rec.pets.herp.

-Yep, I read the rec.aquaria and I cannot believe most of the stuff.
Unless there is some literature on the topic I have a hard time with the
info.  I am not saying that it does not exist but that the rec.anything
lists are cess-pools of really bad info.  Most of the problems that occur
on the list could be remedied with a water change.

>Imagine if the native flagfish all survive the
new invader, but all the pygmy sunfish fail to produce any antibody.
Then a population that was not even figured into the equation is gone.

-The introduced species - healthy - does not bring in disease but new
genetics.  I do agree that a sickly fish may destroy other populations -
good point.

Robert wrote:
>A good negative example are the many game birds(pheasants , turkeys etc )
that have been pen reared for  X generations and are now being releases
to shore up wild populations. they end up weakening the wild stock
because in a domestic enviroment passive is good , flighty is bad ...in
Nature generally the oppisite is true ...Back to lurker mode

-Looks like it will be a good hunting season for turkey hunters;-)

Mark wrote:
>So apart from the theoretical genetic benefits or detriments, it's still
just not a good idea for hobbyists or whoever to be relocating and
releasing animals into the wild.

-I have agreed with that from the get go.  I agree with your two cents -
introduction of new genes into a site does screw up Ph.D. student genetic
studies (;-P) but I am looking at it from the stand point of the wild
population.  Not some thesis or dissertators project.

Dwight wrote:
>...Birds were released and
interbred with the resident quail.  Winter came and the entire
population was exterminated except for some isolated pockets of quail
that hadn't been mingled with their southern kin.  Seems that  the F1's
did not have the appropriate genetics to deal with northern winters.

-Did that happen the next winter with the F1's?  The Southern species
survived though, right?  One generation does not tell us much other than
not much survived in the F1s.  The next F1 generaton may (conjecture - I
agree) have had a few that survived the winter thus conferring a new set of
genetics to the local population that may allow them to survive a totally
unknown disease that the native population had never seen but the Southern
birds had.

That was fun.  Hopefully the discussions will stay lively and fun.  I am in
no way out to get anyone or to make for myself a negative reputation.  I
mearly want some interesting discussion and to learn.

Matthew T. Mason
Doctoral Student
The Ohio State University
Department of Molecular Genetics
mason.163 at osu_edu

The most absurd and reckless aspirations have sometimes led to
extraordinary success.