Management of invasive freshwater fish: striking the right balance!

Management of invasive species is integral to, the maintenance of freshwater environments. Habitat protection alone will not protect the full range of indigenous communities or ecosystem services. It is also contentious as it may involve. removal of valued introduced sport fishes. An invasive fish can be defined as any species that significantly adversely affects the long-term survival or genetic variation of native species, or the integrity or sustainability of natural communities. Implications for sport fish, particularly trout, must be considered within the context that they are valued by the public, have statutory protection, and their presence contributes to conservation of New Zealand's fresh waters. Standard pest management criteria also demonstrates that widespread management of some sport fish species is likely to be neither socially acceptable, nor technically or fiscally feasible. Nevertheless there will be circumstances under which management will be required. Invasive fish may also include exotic fish that threaten valued introduced species, or impact upon waterway condition and services. The continued spread. of introduced species indicates that management of invasive fish requires urgent attention and a coordinated multi-agency approach. Any response should draw upon established terrestrial pest management frameworks, and the experience of terrestrial pest operations (national and international), island eradications and international fishery restoration programmes.