RE: Further thoughts on SMP -- from Dave's response sort of a refutation

["Griffiths, Richard" <rgriffit@visa.com>]

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>Sure, there are anecdotes like this, but this was pure chance.  There is no
>evidence that such a situation would have the same result with fish or any
>other organism.  In fact, I can think of other anecdotes from the aquarium
>hobby in which the abililty to breed certain aquarium strains became
>increasingly difficult from generation to generation, most likely due to
>effects of inbreeding.  

While I appreciate your dialog, your third sentence above is very
misleading and highly inaccurate when you consider the selective
genetics of the guppy, swordtail, platy, betta, and molly. And I
disagree with it based on genetic and personal experience.

Continuous line breeding for 30+ generations (brother to mother; brother
to sister, etc.--especially in livebearing fish, and from brother to
sister with cichlids, killies, and anabantids, and for some of these,
10-15 years worth of breeding) continues many very successful 'fancy'
varieties, and even wild stock of fish, of the currently extinct fish,
or threatened fish, show no 'inbreeding' characteristics of which people
often speak--due to picking out the best of the breed and working
through that. 

Ask guppy breeders about their breeding techniques. They don't
'outcross' to maintain their particular genetic stock (unless they are
trying for something new). Endler's livebearer, black pearlscale angels,
original angels and later, the other two species of angels starting with
MINIMAL numbers (up to 8 fish I believe, 3 breeding), and some halfbeaks
in this country come from single pairs of fish back in some forgotten
time (by most), and they do not show, again, inbreeding problems. 

While fish in streams, rivers, ponds, and lakes have the ability to
travel, most remain relatively in the same general area, thereby
reducing their genetic diversity  by not traveling to somewhere else in
the area, i.e., 20 miles downstream. If collections are done along a
stretch of a river for the same species, there is some genetic drift as
isolated pockets do develop--that's what happens in the hobby as well.
But where do you draw the line of what is a species, what is acceptable
for maintenance as opposed to maintenance of every conceivable 'genetic
drift' combination you might find? I don't have an answer to that.

One other thing. While we hobbyists, aquarists, individuals have a
concern, the ichthyologists who run refugia or breeding plants, don't
count like to have less than, say 100,000-1,000,000 fish for a genetic
base. With those numbers in a population, there is certainly genetic
diversity. We, on the other hand, are happy to get a breeding pair of
something to work with. And by that nature, anything we work with, is
highly likely to be from a single pair (especially of a rare fish).
Can't get away from that unless we collect multiple specimens on our
own.

>One cannot predict what the overall effects of an
>artificial selection program will be; sure, we can cull the dullest looking
>individuals, but how do we know we're not culling the best breeders at the
>same time?  We won't know until the next generation, and by then it's too
>late.
True, you never know about the 'best breeders', but if you pick healthy
stock from the beginning, the breeding does get easier. Case in point,
the Bell Isle Aquarium first bred one of the dwarf stingrays from the
Amazon, and now multiple generations of the fish are distributed to
other national aquaria, and many are into their 3rd or 7th generation.
Again, from limited stock. But each generation gets easier to work with
since we know more about the fish and their needs. And that's the issue.
How to achieve the best environment for that to take place in.

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>Obviously, we need to be perfectly clear about our goals and intentions 
>when designing a species maintenance program.

I would agree whole heartedly. Whether it is to protect the fish from
true extinction in the wild by having 'safe houses' where fish will
always be kept and maintained, or if it is to provide the hobby with
fish in the future. The problem is, of course, each individual's
interest, limited resources, and perception of the need. It would only
take about 5,000 dedicated aquarists each keeping one species going to
preserve all the fish we have, or have had, or are likely to have in the
next 10 years, going in a SMP environment. Unfortunately, there are less
>than 500 (by a long shot).
>-Dave
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>-David Ranney
>-dranney@alvord.k12.ca.us
>-Science Teacher, Technology Coordinator
>-Wells Intermediate School
>-(909) 351-9241
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