Re: NANFA-L-- Re: Chinese Sturgeon on AquaBid

Peter Unmack (peter.lists at)
Thu, 11 May 2006 11:20:09 -0500 (CDT)

On Thu, 11 May 2006, Jerry Baker wrote:

> This isn't a rhetorical question. Why is it that fish taken into
> captivity learn to act differently quickly, but cannot do the same when
> placed back in the wild? Can they only learn once?

Because in the process of learning they most likely die! (I said that
just for you Martin.) I'm used to keeping wild fish and they tend to be
easy to unsettle in captivity. In my minnow tank-in-home the fish still
freak out anytime anything goes by too fast or overhead, even when I move
very slowly and carefully (fish have been in captivity for about a year).
I was recently-in-a friends place in a tank with mostly guppies and a few
other fishes, and you could have done anything to them and they would
still be swimming around-in-the front of the tank completely unphased.

I think it is that natural fear of many things that really helps these
guys survive in the wild. But you also have to keep in mind that in
captivity, most individuals survive, whereas in the wild very few survive.
Thus when releasing fish into the wild, you would expect to have massive
mortality just as if they were being born in the wild. Thus introducting
1000 topiminnows might only really be equivalent to establishing 10 fish
in the population.

Peter Unmack
Provo River, UT
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