> I have a question for the group. I recently collected some rainbows from
> an unnamed creek in the Dawson River drainage near Theodore in Central
> Queensland. My question is this all the distribution maps I've seen say
> they should be M splendida spledida however they are clearly either M.
> duboulayi or M. fluviatilis. Does anyone know about the species that are
> meant to occur in the Dawson? I am wondering if maybe they are stocked
> dam escapees.
The Dawson is an odd river (as well as other Fitzroy River tribs) in that
it has two rainbowfish species, or at least a mix of two (or three
actually). They look like fluviatilis, but have a mix of splendida,
fluviatilis and duboulayi genes. Quite a mess really! The duboulayi part
comes via the northern Murray-Darling Basin as duboulayi mitochondrial
haplotypes dominate in some northern areas (eg, Condamine, which probably
originally came via the upper Burnett River), from here they have moved
north within "fluviatilis" into the upper reaches of the Fitzroy.
Anyway, that's the short explanation.... Gunther and I are supposed to be
writing up some stuff on this area...but alas, other tasks prevent me from
getting started. It is a fascinating region and makes a complete mockery
of the idea that rainbows don't hybridize in nature (well, many don't seem
to, or at least not much, but some do a lot).
Did that answer your question? :-) Oh, and there is no evidence that
this is anything but a natural occurance, eg, it isn't due to human
disturbance and/or introductions.
Cheers
Peter Unmack