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Re: species maintenance database att: Lee Harper

>Lee has brought up an interesting dilemma we are facing in long term
>maintenance of a species. As noted, I am heading the Aphyosemion australe
>(chocolate) Core Species. Our founder fish are "aquarium strain" as they have
>been in the hobby many years without wild importation until the last few
>years. We have striven to keep a sort of genetic code on all founder fish and
>have been exchanging among one another. The chocolate australe continues in
>apparent good health with good coloration and no bent spines nor other
>deformities. A number of wild strains have been imported the past three
>years, one from Cape Esterias and the other from Cape Lopez. Grossly, the
>fish appear the same. Now comes the question of whether or not we should MIX
>the wild strains with the aquarium strain! The purists say NO! However there
>is no real argument as to the species of this fish. It appears the "perfect"
>example for mixing in wild strains to increase the genetic diversity. If we
>don't mix the wild strains we continue to inbreed the aquarium strain for no
>good purpose. I am not mixing the strains yet, but need direction for the
>future.
>
>I fear this is really opening a "can of worms" as mixing various collection
>sites is a no-no for fear the fish are different. As mentioned, the AUS is
>not different. If we don't mix them now, how long shall we wait to mix the
>fish between wild and aquarium strains? Is the time -- FOREVER?
>
>                                                       Harry Specht

Harry,

I would argue against NOT mixing the strains. At least as a minimum 
you should keep pure stocks of the recently imported known locations. 
Once you mix them the resultant progeny are aquarium strains and must 
be distributed without location data.

The reasons for not mixing are:

1. You can only say that the fish LOOK the same. You can't say that 
they ARE the same.

2. In my opinion you can't say that you are increasing genetic 
diversity by mixing with present inbred aquarium strains. If the 
latter are inbred you presumably could reduce the genetic diversity 
of the progeny rather than increasing it. The best way to sustain 
genetic diversity, I think, would be to start with the largest 
possible number of founder fish from the particular location. In 
saying that I am fully aware of the fact that the number of original 
imported fish is often small.

3. There is nothing to say that inbreeding is necessarily bad. If the 
australe that are presently in the hobby are inbred but look exactly 
the same as the wild strain, then what is the evidence that they are 
either inbred or that any inbreeding has been deliterious? In general 
inbreeding is regarded as undesirable, but inbred strains can be 
developed that are quite robust. Look at the world of the laboratory 
mouse for examples.

Barry
Barry J. Cooper				Phone: (607)253-3336
Dept. Biomedical Sciences			email: bjc3 at cornell_edu
College of Veterinary Medicine
Cornell University, Ithaca, NY 14853
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