Re: New Fish Room -Reply

[cfonda@sentientconsult.com]

Jerry wrote:
:Wouldn't the greater danger be that you could be developing a strain of
:fish which have a weakened immune system which would not be strong
:enough to keep the fish healthy without the assistance of a sterile
:environment?  The other problem might be the development of mutations of
:the bacteria and viruses being exposed to the UV or ozone which are
:resistant to the UV and/or ozone.
:
:In either event, these are long-term to very, very long-term problems
:(how long would it take to develop a strain of fish with a deficient
:immune system).
:
And Kym responded:
 :i dunno, personally, i think that this is a somewhat moot point, i don't
see
:how we really can be affecting the evolution of the fish, and their future
:behavior, in such a short time, evolution takes thousands of years.  One
or
:two batches of fry won't matter, to my way of thinking.  However, i am NOT
a
:biologist, just an engineer, so maybe the fish's short life spans might
make
:a difference, i only know what i've read about humans and animals.
The possibility of developing a strain with weak immune systems is very
remote and not really a concern.  The concern is that fish raised in an
environment with a minimal number of pathogens will not develop the normal
assortment of antibodies.  During development, an animal develops
antibodies to pathogens as it is exposed to them.  The antibodies are
fairly specific to a given pathogen and exposure to that pathogen is
required for the antibodies to develop properly.  Here is the kicker:  an
animal will develop antibodies and fight new pathogens more effectively
while in its youth.  The adult immune system relies more strongly on
antibodies developed during its youth than on its ability to develop new
antibodies.  (Which is why many diseases, like chicken pox, that are mostly
a nuisance to children can be deadly for adults.)  So the concern is that a
batch of fry raised to adulthood in a sterile environment will have
weakened immune systems, not as a result of genetic factors but rather as a
result of purely biologic factors.

--Cliff



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