> The number of established exotic freshwater fish species in Australia is in
> the range 19-24 (Arthington & Blühdorn, 1995). Of these species only 10
> could be considered aquarium fishes,(5 Poeciliidae, 3 Cichlidae, 1
> Cobitidae, 1 Cyprinidae). Most of the Poeciliidae were Government controlled
> releases for mosquito control, leaving 5 that can be directly related to
> aquarium release and 2 of these are confined to artifically heated pools in
> Victoria.
I'd like to despute your assumption that all 5 poeciliids are govt
releases. I'm sure some of the guppies, platties, and swordtails came
from aquarists. I dunno about the Phallocerous caudimaculatus in WA as
to if they were govt or aquarium releases. Some of todays releases of
"dambusia" are caused by many non govt sources too, farmers, kids with
buckets, etc. However, there can be no disputing your point regarding
how few fishes have become established relative to all those that come
in. An alternative way to look at this though is how many exotics have
been recorded, ie released, but not persisted? I few examples that I
know of include swordtails and P. caudimaculatus in the Todd River in
Alice Springs (almost definately aquarium releases), Jordinella floridae
in Harveys Creek (one of Allen's papers/books), Tilapia in Lake Burley
Griffin, Empire gudgeons in Lake Wyangala (Lachlan River) (unconfirmed
report-likely angler bait release), Delany's Creek duboulayi have been put
in farms dams on the other side of the mountain outside of the Brisbane
River drainage and I'm sure there are many other examples. Anothr big
concern that I have is how many people in tropical parts keep fish
outside in ponds? What happens in a cyclone? Also, most of the
fishkeepers in Oz live in areas where most
tropical fish won't survive. In Victoria, through the Flora and Fauna
Guarantee Act it is now illegal to translocate native or exotic fish
between localities in the state without appropriate permits. That is the
kind of legal power at least that is needed to begin to address some of
these problems. Making live fish illegal as fishing bait would help too.
Further though, when a native gets translocated how can
you tell? If the same, or similar species already occurs in that area
it won't be noticed until someone studies the fish genetically and even
then you can't be definite that it was a translocation.
My main point in all this is not that aquarists shouldn't be keeping
fish, but that aquarists shouldn't hide from some of the facts and
problems either. What we need is positive actions from aquarists /
aquarium industry to deal with the current problems, otherwise the
industry lacks credibility IMHO.
A further question for the Qlders, where have all the Tilapia in Qld
been coming from (ie govt, aquaculture, aquariums, etc) and what are the
causes of their continued range expansion?
Tootles
Peter