Re: Lets be careful
Walter Ivantsoff (wivantso at rna.bio.mq.edu.au)
Wed, 22 May 1996 10:53:25 GMT+1000
Andrew Boyd is wistful about the fact that the Americans can get all
the fish they need from New Guinea and Irian Jaya. I did not comment
immediately as I thought it would be prudent to check the status of
importation of fishes into the United States.(New Guinea authorities do not
allow export without permits either, I remember spending half an hour with
customs even after showing my New Guinea export permit to take out not live
but frozen fish). Andrew would find that for Americans, import licences
are necessary and these are not easy to get. However, their damage is
already done. If Andrew would check on the numbers of exotic fishes which
are now in the wild south-eastern states of U.S. I am sure that he would
not wish the same situation to befall upon us. I am not saying that
responsible ANGFA members would ever be guilty of wilful releases but
casual aquarists do it all the time, witness the fact that you can catch
yourself all sorts of exotics around Brisbane (call on Rolly McKay at Qld.
Museum and he will provide you with a list). Also, I am told that after a
tornado one year, there was a massive escape of fishes into the wild and
there they are to stay. Andrew may wish to import rainbows but I know for a
fact that north Queenslanders wanted to import the nile perch and quite a
few people would love to have as many species of cichlids imported as one
could lay their hands on. Why should they be refused, they may be as
passionate about pirahnas and snakeheads as we may be of rainbows? We have
just over 200 species of our own fish to work with, many not known too
well and quite a few to be discovered yet. Why not be content with our
unique fauna? Peter Unmack has a point about hybridization. Lucy Crowley
in 1985 worked with a number of rainbows and was successful in hybridising
all the species she had. Andrew may rightly point out that the fish may not
hybridise in the wild but then again, we have no experimental data to
indicate that this is so. Furthermore, we have no data on how the exotic
fish may effect local species and how they may influence the local
environment. A quick look through a book called "Battle Against Extinction"
by W.L.Minckley and J. Deacon (1991, The University of Arizona Press),
dealing with freshwater fishes in the American west, points to
incontrovertible evidence that very closely related species do hybridise in
the wild (especially when there is environmental pressure) and these are
tooth carps which phylogenetically are closely related to atheriniforms of
which rainbows are members. Native N.G. rainbows may carry microorganisms
to which the Australian fish have no resistance. If that may be the case,
our native fishes may be severely affected. I have no data and neither has
any one else. All the more reason to be careful. I suppose the response may
be that diseased fish can be treated with antibiotics ( I note much
correspondence on this). At a fish disease conference in Benala some years
ago, one of the most eminent Australian fish pathologists pointed out that
both vets. and medicos treat their patients with antibiotics with gay
abandon thus selecting out resistant microorganisms the infection with
which may now be untreatable. It seems that even in the right hands use
of antibiotic treatment is a dangerous weapon. I note with interest that
many of the correspondents comment on colour variability and other
variations that they have noted within the same "species". I don't really
know how many rainbow species there are since presently used criteria for
defining species fail to delineate that taxon.There is still a lot of work
to be done just to find out what we do have. Giving a name to a population
of fish does not make it an immutable species. I fear that until we
delineate our populations of rainbows with some accuracy, chance
contamination of stock with exotic imports will forever destroy our chances
of finding out as much as we can about natives. Perhaps the urge to have
just one more beautiful fish that no one else has can be suppressed for
the sake of responsibility to our environment and biological heritage. I
am not a member of any advisory organisation and the opinions I have
expressed are solely mine. I understand that Professor Angela Arthington
(Griffith University) has been involved in studies of introduced species.
Perhaps she should be invited to join the list and contribute her opinion.
Yours sincerely,
Walter Ivantsoff
(e-mail wivantso at rna.bio.mq.edu.au)
(phone 61 02 850 8167)
(fax 61 02 850 8245)
(and if all above fails write a letter to:
School of Biol Sciences, Macquarie University
N.S.W. 2109, Australia)