City of Playford managed aquifer recharge scheme: carp eradication program.
This study was conducted to: (i) utilize rotenone to eradicate carp from five interconnected water bodies associated with the managed aquifer recharge (MAR) scheme owned and operated by the City of Playford, South Australia; (ii) report changes in turbidity associated with the eradication of carp; (iii) evaluate the likely mechanism of the initial (and future) carp incursion and subsequent spread throughout the scheme; and (iv) provide management recommendations for the ongoing control of carp within MAR schemes. Results showed that rotenone is an effective tool for controlling carp in constructed urban wetlands. As a result of the rotenone carp eradication program, a total of 26 706 carp (12 381 kg) were removed from across the City of Playfords MAR scheme between 2014 and 2016. Substantial improvements in turbidity were observed within two days across all rotenone treated wetlands indicating that carp were the primary cause of elevated levels (<20 NTU). However, the ease with which carp infestations can occur/persist and the cost associated with continual removal highlights the need for management strategies that aim to mitigate future incursions and the spread of carp throughout the scheme. The most appropriate strategy is to eradicate carp from across the entire system over one concerted eradication campaign and discourage cross catchment translocation via a public education program. This strategy is likely to yield the greatest long-term benefits by eliminated seed stocks from within the catchment and attempting to mitigate translocation of carp from neighbouring catchments.