RE: Heterozygosity and Rainbows

Bruce Hansen (bhansen at oznet02.ozemail.com.au)
Mon, 3 Jun 1996 00:16:51 +-1000

From: Cary Hostrawser[SMTP:caryho at ix.netcom.com]
Sent: Sunday, 2 June 1996 23:15
<< I know there has been some discusion by folks working with
threatened species that some species have very little heterzygosity in
their gene pools and crossing them with the same species from other
collections actually hurts the viability of the captive species.
Basically you bring in bad genes to a stabilized population and the
species suffers. I believe they term the condition out-breeding
depression as opposed to inbreeding depression. Both can be a problem
that could wipe out our captive populations.>>

Unfortunately these factors only come to light when things are getting desperate, and I guess it is only just another manifestation of Murphy's law.

<<I just think we need to make a few notes and publish them on which
species are suffering from either of these two conditions. So future
bow keepers can learn from our mistakes and successes.>>

We have a few species that have disappeared - mostly PNG Rainbows but I'm not sure if they were lost due to "depression" of the genetic fitness of the stock. It was more like there were not enough concientious and capable breeders who were prepared to put

the effort into relatively unattractive species. I probably couldn't give an exhaustive list but Chilatherinas such as crassispinosa, bulolo, sentaniensis; Glossolepis multisquamatus is another fish I haven't seen for quite a while. Also Melanotaenia mon

ticola, perhaps oktediensis etc etc

I agree we need to try to keep track of stocks - i. e. who has what and how many and try to ensure that at least 4 or 5 populations are in existence to draw from as well as some idea how each of them is "performing"

Bruce Hansen ANGFA.