Re: [RML] Peter-Different populations

peter.unmack at ASU.Edu
Sun, 09 Apr 2000 18:13:45 -0700 (MST)

On Mon, 10 Apr 2000, Dennis Holmes wrote:

> if Fish where cought in mountain creek's compared to low land they should be
> differant- what sort of distance would you say this would happen 10km 30Km
> Say Springbrook to Coomera?

Typically you need a longer distance than this. While I agree with Bruce's
comments on there being differences within drainages I tend to think that
these tend to be minor, or very hard to detect in many cases, although there
are many well known exceptions. One problem with rainbowfishes is there are
no, or at least very few generalisations one can make that will apply to them
all! Mostly it depends upon the size of the drainage (Coomera River is piddly
compared to say the Fitzroy), and also whether there might be waterfalls
present (very important in the Atherton Tablelands region). Also too, some
people seem to be better at finding differences between populations than
others. :-) Some populations vary depending upon the time of year too, one
year they'll bring back fish that are one colour, next year from the same site
they will get one a different colour. Could just be due to limited sample
size, or it may indeed be real. You will usually find more difference though
between rivers, i.e., the Coomera and Nerang rivers than you will find within

Peter J Unmack peter.unmack at
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