Let's leave out hybrids and selected sports for the moment and talk about
maintaining species in captivity as "wild" types.
> Yet I will not be convinced by anybody that the F1 to Fx generations of true
> species bred in aquarium (or farm - no particularly farm) situations are
> true representatives of that species.
That statement presumes there is a definition of what a true
representative of that species is. Would you like to try and define
that? Not likely. :-) Based on your comments it is a suite
of characteristics, genetic, behavioural, morphological, biologicial etc
etc. I think we could agree that defining genetic and morphological
wouldn't be too difficult. The rest are much more difficult. And also,
by constraining a species to a set type we have just defined evolution as
being a negative thing. Species are not fixed static entities, they are
potentially constantly changing. So, how do you define a dynamic
entity? :-)
> Their behaviour appears to change.
> They forget how to forage for wild foods. Perhaps they forget what defines
> an ideal natural breeding location, and even an appropriate spawning season.
Are behaviours fixed? Can they be unlearned and relearned? Does it matter
if aquarium stocks have different behaviour? What are we trying to do
here, save species or put them in people's aquariums for their
enjoyment?
There is no doubt that behaviours change when an organisms environment
changes. If they didn't then most organisms would be screwed. While many
behaviours have a genetic component to them, most are strongly influenced
by their environment. Look at that paper by Calum Brown on rainbowfish
behaviour, it is different in each environment. It's all the same species
though, with the same common ancestor, they have just learned how to
survive under different circumstances same as they do in aquaria. Does
that mean that aquarium fish lose forever their potential to have wild
behaviours again (whatever we can't define them to be)? Has anyone tried
raising fish from captive specimens under wild circumstances and comparing
their behaviour? Not really. Bruce, what do your fish inside do when you
walk into the fishroom? They all come up to the glass looking for food.
What do the fish outside in your pool do (that you don't feed) when you
walk up to them? Run and hide I'll bet. Behaviour is incredibly flexible
(just consider people) and is strongly influcenced early in life. While I
think we are wise to be concerned as to the effects of captivity, we worry
too much about it.
I should also point out that in conservation programs among birds and
mammals few have been successfully raised so that they could survive under
natural conditions. However, I think fish are much easier to work with as
they can be raised without human attention under the right circumstances
and in much greater numbers. Also, think of all the introduced species
that were captively raised and then relesed into the wild? Obviously
their behaviours changed to meet the change in environment.
> What I am implying is that aquarium bred fish are potentially as untrue
> examples of the "real thing" as are hybrids.
I think the differences we percieve between wild type and captive are
less significant than we make out. We make out that if the red colour in
the tail of fish changed to yellow that everything is doomed. Big deal I
say. The long term evolutionary significance of this is not likely to be
significant. There is always a possibility it could be, but it my
opinion this is not that likely.
> Having said that I am also a realist. I believe that humans are destined to
> manage the entire biosphere in order to survive. Although it is unlikely I
> will ever have the resources to prove it, I believe that human activities
> have already modified the behaviour of red-finned blue-eyes in their natural
> environment.
So what? What are the implications of this statement? What does it
really mean if we have modified them in some way? This species and it's
ancestors have been swimming around for millions of years. They have
probably been modified in many ways with climate change, habitat change,
new species invading their drainage etc etc. Should we just toss them
away as being unworthy for conservation now? I would agree that it's nice
to keep them as wild as possible, but I think it is mostly so that humans
can be pleased with themselves having done a good job managing that
species rather than the long term evolutionary implications. We like to
keep things "wild". I don't think the fish realise this or care too much
about it. As long as they spread their gametes and bring along another
generation and don't die a miserable death they are probably satisfied.
That should be enough philosophical crap to last you for a long time
Rob. :-) Of course, nothing is real, it's all just a perception..... of
which we all have a different one.
Tootles
Peter Unmack