Threat abatement project
Prepared by: D. Rowe, A. Moore, A. Giorgetti, C. Maclean, P. Grace, S. Wadhwa, J. Cooke for the Department of the Environment, Water, Heritage and the Arts, May 2008
About the report
The introduction and spread of alien (i.e., non-native) species is regarded by many as a major threat to global biodiversity and hence ecological sustainability. In particular, studies of fish introductions to freshwater ecosystems in the Northern Hemisphere have shown that some species can reduce native fish populations, degrade aquatic habitats, compromise gene pools, and increase the risk and spread of alien diseases and parasites. As a consequence, the introduction of alien fishes is a major cause of biodiversity decline in freshwater ecosystems and, on a global basis, fish introductions are a prime cause of the extinction of many indigenous fish populations.
The Australian continent contains a relatively large number of endemic aquatic fish species that form unique component to the biodiversity of its aquatic ecosystems. The wide range of climate types present (e.g., tropical, continental, temperate, island) combine with its diverse geological terrain to provide a large number of fish habitats and these contribute to the relatively high biodiversity of the endemic fish fauna. But these factors also mean that the Australian freshwater fish fauna is vulnerable to the impacts of alien fish species.
The purpose of this review is to bring together all the information relevant to the impacts of six individual species and to identify gaps in knowledge so that DEWHA can develop and support initiatives to better manage the environmental consequences of these species. The species considered in this report are Gambusia holbrooki (eastern gambusia); Perca fluviatilis (redfin perch); Tinca tinca (tench); Rutilus rutilus (roach); Acanthogobius flavescens (yellowfin goby); and Acentrogobius pflaumi (streaked goby).