Overview of the feral Goldfish Control Programme in the Vasse River, Western Australia: 2004-2006
Beatty, S.J. and Morgan, D.L. (2006) Overview of the feral Goldfish Control Programme in the Vasse River, Western Australia: 2004-2006. Murdoch University. Centre for Fish & Fisheries Research, Western Australia.
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The establishment of introduced fishes outside their natural range is often facilitated by a wide tolerance to environmental regimes, maximisation of reproductive potential, high genetic diversity and tendency for good dispersal mechanisms (r-strategists) (Stauffer 1984). An expression of a broad diet (e.g. omnivory) and the ability to tolerate degraded habitats also enables exotic species to exist and flourish in foreign environments. Within Australia, examples of omnivorous species that are highly adaptable to an array of environmental conditions include some of the poeciliids, cichlids and cyprinids; groups that are all traditional aquarium species but are naturally absent from the country (see Morgan et al. 2004). While the ecological impacts of some members of these groups are well understood, there is little information with regard to one of the most widely introduced freshwater fishes of the world, i.e. Goldfish (Carassius auratus). Feral populations of Goldfish have been reported from almost every state of Australia (McKay 1984, Koehn and MacKenzie 2004) and indeed are now found throughout much of the world (e.g. Fuller et al. 1999, Skelton 2001). They are also established in almost every state of the United States and are thought to be the first foreign fish species introduced into that country (e.g. Fuller et al. 1999). Goldfish have been implicated with the introductions of parasites to South Africa and Australia (Fletcher and Whittington 1998, Mouton et al. 2001, Hassan, Morgan and Beatty unpublished data) and with the decline of a number of native fishes in the U.S. (Deacon et al. 1964, Moyle 1976).
Within Western Australia, Goldfish are generally restricted to the south-western corner in the vicinity of major population centres where they appear to be most successful in modified or degraded waters (see Figure 1 and Morgan et al. 2004). The only previous biological study (growth and feeding) of wild Goldfish populations in Australia was conducted by Mitchell (1979) who used scales to age fish from South Australia, while Izci (2001) determined growth rates and age and sex compositions for a wild population of Goldfish in Lake Eğirdir, Turkey. The main aim of this study was to implement an ongoing control programme for Goldfish in the Vasse River and thereby reduce the biomass of the species. Secondary aims were to examine the distributions, habitat associations, age compositions, growth rates and diets of Goldfish in this eutrophic waterbody and to develop an understanding of factors contributing to their success.
|Murdoch Affiliation:||Centre for Fish and Fisheries Research|
|Series Name:||Murdoch University Report to Geocatch|
|Publisher:||Murdoch University. Centre for Fish & Fisheries Research|
|Copyright:||2006 Murdoch University. Centre for Fish & Fisheries Research|
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