Once you release an organism into an environment, it is very hard to
predict the outcome of that liberation. Attempts to establish carp
populations in Australia were made last century, but failed. It was only
in the 1960s that a "successful" liberation was made.
Hybridisation has occurred amongst several Australian species in the wild
when normal separating mechanisms have been disturbed. One near to my
heart is the population of Murray cod and trout cod in Cataract dam in NSW.
This population was originally stocked before the difference between the
two species was recognised. Now the population contains many hybrids, and
is lost as a potential source of trout cod for the trout cod recovery plan.
Recently Australian bass and estuary perch have been found to hybridise.
Yes these are all large species, but the principal is the same. Do not try
to convince me that no one here has seen hybrid rainbowfish, we all have.
They _may_ not hybridise in the wild, but I am not prepared to run the
risk.
I think it is nonsense to say that two closely related species from
different catchment systems definitely will not hybridise. How do you
know? If the separating mechanism is geographic, then introducing one to
the other system has all sorts of potential dangers, and is very
unpredictable in consequence.
The precautionary principal would suggest that we should be very careful
about such introductions. If we are to allow such species into the country
then I would only agree to it if satisfactory permit arrangements were in
place. We do not have any sort of _natural_right_ to hold whatever fish we
like. Just because you are interested in some fish does not mean that as a
community we should ignore all potential threats to our indigenous fauna
just to please you.
I would suggest that the burden of proof should lie upon the proponents
that such an importation is for valid reasons, that satisfactory
arrangements will be in place to PREVENT the introduction of such fish into
the wild AND into the general aquarium hobby. Are you prepared to do
this? If not then I oppose you most strongly.
Bruce, I think you are wrong in your assertions about the introduction of
PNG species into Oz. You seem to forget that two wrongs do not make a
right. Just because we have done stupid things like introduce trout, carp,
redfin, gambusia et al, it does not mean that we should turn as blind eye
to further introductions. I suggest that we should learn from these
examples and make bloody sure that it does not happen again.
Nick
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Nick Thorne nick at nativefish.asn.au
Native Fish Australia http://www.nativefish.asn.au