Journal of the Royal Society of Western Australia, 90(3), September 2007 
lengths larger than can be consumed by native fishes). 
Goldfish, as a benthic generalist/herbivore, has been 
shown to cause increased turbidity and deplete aquatic 
vegetation (Richardson et al. 1995). A reduction in 
aquatic vegetation reduces habitat and potential 
spawning sites for native fishes. 
Very little is known of the parasites infecting 
freshwater fishes in Western Australia; however it is 
acknowledged that non-native parasites may use 
introduced fishes as vectors to infect native fishes. 
Goldfish are known carriers of a number of serious 
diseases and have been implicated with the introduction 
of several fish pathogens in South Africa (Mouton et al. 
2001 ) and at least one monogenean trematode in 
Australia (Fletcher and Whittington 1998). Screening of 
parasites and diseases within captive populations of 
Goldfish is crucial in the detection of potentially harmful 
organisms. 
Tine implications for the activation of cyanobacteria 
blooms after passing through fish digestive tracts are 
serious when considering the widespread distribution of 
Goldfish throughout the world, where they are 
predominantly associated with urban areas. A number of 
other fishes that have been introduced throughout the 
world, including within Australia, consume 
phytoplankton and thus have the potential to stimulate 
cyanobacteria growth in nutrient enriched environments. 
Specifically, feral populations of Tilapia (Oreochromis 
mossambicvs), One-spot Livebearers {Phalloceros 
caudimaculatus), Swordtails (Xiphophorus helleri) and 
Carp {Cyprinus carpio) are not only established within 
Western Australia (Morgan et al. 2004), hut most of these 
species have been introduced throughout the world. The 
control of algal blooms may be aided with eradication 
programs of feral detrltivorous fishes inhabiting nutrient 
enriched environments worldwide. 
Acknowledgements: Funding and project partners for this project 
included Ceocalch, Fishcare WA, Fisheries WA and the Vasse-Wonnerup 
Land Conservation District Committee. There was al.so strong community 
involvement and support for the project and in particular we would like 
to thank Gilbert Stokman, Veronica Piper, Annaleisha Sullivan, Dane 
Hordacre, Michael Burgess, John McKinney, Jenny Mitchell, Craig 
Astbury, Howard Gill and Dan French. 
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