Floodplain degradation and restoration in Northern Queensland: The response of the Alien Fish Pest Gambusia holbrooki

Abstract

The Burdekin River basin is one of Queensland’s most important areas in terms of primary production, with sugar cane production dominating the delta region. Extensive clearing – as well as extensive irrigation which has altered the hydrology from naturally intermittent to artificially perennial – has greatly changed fish habitats on the delta (Perna 2003). Changes in hydrology have greatly benefited aquatic weeds, which in turn has greatly reduced dissolved oxygen content in the waterbodies (Perna 2003; Perna & Burrows 2005). Large-scale physical removal of aquatic weed infestations by floating harvester and excavator has been shown to greatly improve water quality, fish habitat and the diversity and abundance of native fishes in two lagoons and a 15 km reach of Sheep Station Creek, a typical floodplain creek system on the delta (Perna 2003, 2004; Perna & Burrows 2005).