Re: [RML] Banning all PNG fish

Bruce Hansen (bhansen at ozemail.com.au)
Sun, 14 Sep 1997 18:55:53 +1000

> From: peter.unmack at ASU.Edu
> To: rainbowfish at pcug.org.au
> Subject: Re: [RML] Banning all PNG fish
> Date: Sunday, 14 September 1997 5:05
>
> annecodotal evidence is not very good
> either. :-)

But it is a starting point - slightly better than none ;-)

> Species that evolve in co-existance have
> things that prevent interbreeding, otherwise they wouldn't exist. But,
> when you through a new species in ontop of this you cannot be sure what
> will happen. One may go extinct, they may coexist, or they may
> hybridise. There is already good evidence of hybrids between rainbows in

> the wild, look at eachemenis and splendida. Another population of
> australis appears to have some exquisita in it. From time to time they
> do interbreed under natural conditions with the end result being that
> sometimes both species don't remain seperate, you get a single hybrid
> population. There is more work continuing on this hybridisation and we
> should have a much clearer picture of eachemensis and splendida in a few
> years.

Agreed. Obviously there must be from time to time ( evolutionary time that
is)
some new invasions from elsewhere. Such things as geological upheavals,
river capture, sea level changes etc are likely to be triggers too. I guess
environmental factors may change enough to favour one of the mutations
popping up from time to time also.

> I agree completely. At this point in time I wouldn't like to see any
> changes to regulations regarding keeping Australian native fish provided
> some stringent educational guidelines were present. We know too little
> about our native fish and at least those aquarists who DOCUMENT their
> observations are doing everyone a great service. Those who are not
> DOCUMENTING their observations aren't really helping near enough.
>
I agree once again ( it is starting to worry me ;-)) Thay's why we bother
to write articles and have these email conversations. It would be nice to
get a few others offering their 5 cents worth too.

> So what do you do Bruce? Just sit here and continue to argue with
> nothing to base any of it on? I think you could easily set up some large

> scale ponds that would easily mimic billabong type habitats. Of course,
> that is if you had the space and money. :-)

Now we are getting down to it. How big? Bigger than the outdoor ponds that
people like Bruce sambell are already using? What about the species that
are really more suited to running water? It sounds good but I don't feel
many of your scientific fellows would like the methodology much and I don't
feel the hobbyist, commercial breeder or even DPI would like it too much.
But it would be a start. I would appreciate the results of a survey of
scientists (especially those in this country who would be on a likely panel
to advise ANCA for example) with their agreement on a size of artificial
billabong, conditions, species mix, time for the experiment to run, data
required, frequency of sampling etc and I will try and get someone to make
the water space available. But I won't be a show at all if there isn't
going to be agreement between the scientists beforehand.

> How do we know it hasn't happened? Remember the massive floods around
> Rockhampton a few years back? I know of one story where a backyard
> commercial rainbowfish breeder lost all his fish due to floodwaters. Is
> that not an introduction? I'm sure no one has looked in his local creek.

I'll bet someone has, and if there was anything worth catching they would
be on the market already.
He's not going to tell the world that trifasciatas are readily available
from the wild now near Rockhampton but he would probably be happy to catch
them and sell them if they were there.

> There are some trifasciata like fish living somewhere near Cairns too.
> Where did they come from? Ask Budgie, Rick Datodi's son caught them
> there. That's a long way south of their native range.

I don't think a few fish caught in an urban creek in a suburb of Cairns (
Freshwater Ck I think - and it has lots of Tilapia, Gambusia, Swordtails,
Platys etc too) really constitutes an example of PNG fish being a threat.
We have always maintained that there is as great or even greater a threat
from translocated Australian fish. This is a failure of education. there is
a large housing estate located on this creek with an especially large
percentage of army families. These regularly are transferred and dumping
the pet fish in the nearest creek probably happens all the time.

As far as the range of trifasciata is concerned - it is moving further
south all the time as further surveys are done and I don't mean in creeks
running through housing estates either ;-)

> . Has anyone else been bothering to read this other than Bruce,
> Rhonda, and I? Everyone else seems very quiet about the issue. Whether
> you agree or think any one of us is full of shit it is nice to get at
> least something!

Come on you guys and gals out there - offer us something. Even if it just a
bone to chew on ;-)
Besides it is only for another day or two then I will shut up for 4 weeks.
See some of you in SF,
perhaps one or two in Denver and heaps of you in Sydney.

Cheers

Bruce