Biotic exchange has been predicted as the main driver of global biodiversity change in freshwater ecosystems. Activities associated with increasing globalisation are facilitating the introduction of freshwater fish outside their native range and dispersal ability. Introductions of alien freshwater fish may be accidental or intentional, and have been made for food resources, recreational fishing, ornamental purposes, aquaculture, and biological control. Introductions of alien freshwater fish can result in negative and positive environmental, social and economic outcomes. Alien freshwater fish are repeatedly associated with declines in native freshwater fish and often eventually account for a high proportion of the total freshwater fish community.
In Australian freshwater ecosystems, the number of alien fish species forming established populations has steadily increased since European settlement. Forty-four alien freshwater fish species have been recorded in Australian waterways; these include five of the eight fish species listed in the ‘top 100 of the world’s worst alien invasive species’ (Lowe et al 2000). The majority of recent introductions (since the 1970s) are alien ornamental fish species, whereas prior to this most introductions were related to European settlement.
Many alien freshwater fish eradication and control programs have been undertaken in Australia, with varying levels of success. The majority of eradication exercises used chemical (rotenone) treatment, while control exercises involved a combination of physical removal by electrofishing, netting and screening, and habitat modification using water manipulation methods. The documentation of management programs is improving, with detailed information on aims, methods, costs, monitoring and outcomes more frequently included. A centralised database would enable the collation, analysis and interpretation of documented management programs, as well as the dissemination of information for educational purposes.
A centralised decision support program would also be valuable to provide easily accessible information to responsible agencies concerning management options for alien fish, the advantages and disadvantages of various methods, and other issues to be considered.
|Author||R Ayres and P Clunie|
|Publisher||Invasive Animals Cooperative Research Centre|
|Department||Freshwater Products and Strategies|
|ISBN/ISSN||Web ISBN: 978-1-921777-21-9|
|Region||Australia - national|
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