Preliminary assessment of oral rotenone baits for carp control in NSW
Non Technical Summary
Carp are a major pest in freshwater systems in New South Wales, and occur throughout the inland Murray-Darling River system as well as in many coastal rivers. There is currently no method for removing pest fish that is specific to any single species. Consequently, all methods currently available for carp control involve some risk to other species.
The development by Prentiss Corp (USA) of a bait system that takes the poison rotenone and delivers it in a manner that affects carp only represents a potential break through in providing real options for carp control. This paper assesses the risks posed by Prentox Prenfish Common Carp Management baits to valuable native fish, and the effectiveness of the pellets against carp.
The system works by attracting carp to eat pellets by feeding them daily on non-toxic trainer baits flavoured with corn. After the training period, floating pellet baits containing a lethal dose of rotenone are substituted to kill carp that eat the pellets.
The experiments described killed only small numbers of carp, but the risks to native species were greater than expected.
This study identified five ways to improve the effectiveness of rotenone pellets against carp and to reduce the risks to native fish. Poisoned baits have potential for use in carp control, but the existing product and application procedures require further development and testing before the method can be considered effective in reducing carp populations, and safe to non-target species in Australia.