generalist ecological requirements indicate that expansion of Carp across most of the remainder of Australia is to be expected (Koehn 2004). Table 2. Attributes of Carp as an invasive species (adapted from Koehn 2004) Attribute Details References Invasion history, wide distribution and abundance Introduced and successfully established throughout Europe, Asia, Africa, North America, South America, Central America, Australia, New Zealand, Papua New Guinea and some islands of Oceania; likely further expansion Lever (1996); Koehn (2004); Zambrano et al. (2006) Wide environmental tolerances Generally in most types of freshwater habitat and have high environmental tolerances: temperature ranges from 2 to 40.6°C, salinity up to about 14 ppt (0.4 seawater), pH from 5.0 to 10.5 and oxygen levels as low as 7% saturation Horoszewicz (1973); Ott et al. 1980); Crivelli (1981); Hellawell (1986); Howes (1991) High genetic variability Multiple genetic strains in Australia Shearer and Mulley (1978); Haynes et al. (2009) Early sexual maturity Males at 1 year, females at 2 years Brumley (1996) Short generation 2–4 Rapid growth Hatching of eggs is rapid (2 days at 25°C), and newly hatched Carp grow very rapidly Balon (1975); Adamek (1998); Vilizzi and
Appendix 5 Site-specific Carp management plans reviewed A5.1. Site-specific Carp management plans reviewed *This is a site management plan that is not Carp-specific. However, it does mention Carp management in brief throughout the report. Authors Location Hydrology scenarios Carp management Other considerations Key recommendations Stuart and Mallen-Cooper (2011) Pike–Mundic Floodplain Complex, Murray South Australia (7000 ha) Existing conditions (i.e. no change from 7000 ML/day entitlement flow to South Australia) Natural flood (50,000 ML/day) Managed inundation for 120 d (1000 ML/day inflow) Discusses operational (e.g. timing, duration and rates of flooding), physical (e.g. barriers, drying, traps) and (e.g. daughterless Carp) control/eradication methods and associated costs Conceptual model of Carp life history within the complex (primarily derived from Chowilla Floodplain Carp data) Potential and benefits for native flora and fauna Broader catchment scale impacts associated with localised Carp recruitment Utilise operational strategies to disadvantage Carp spawning/recruitment while maintaining/enhancing the habitat/hydrological conditions for native fish: operate regulators to maintain a mosaic of flow habitats reduce frequency of managed inundations, but take advantage of natural floods prioritise managed inundations for winter, but seek to understand broader ecological consequences plan for managed recession before water temperatures reach ~15oC adopt operational regimes that maximise flowing water habitats. Physical interventions are not recommended until baseline knowledge gaps regarding basic Carp biology are filled. Implement a monitoring framework to gather basic information to inform future changes in hydrology and management.
Stuart et al. (2011) Chowilla Floodplain, Murray River, South Australia (~17,700 ha including anabranch and floodplain systems) Within-channel stable flows (7000 ML/day entitlement flow to South Australia) Natural (e.g. 30,000 ML/day) Managed inundation (>75% flowing water retained) Managed inundation (<25% flowing water retained) Discusses operational (e.g. timing, duration and of flooding), physical (e.g. barriers, drying, traps) and (e.g. daughterless Carp) control/eradication methods and associated costs Conceptual model of Carp life history within the Chowilla Floodplain Potential risks and benefits for native flora and fauna Broader catchment scale impacts associated with localised Carp recruitment Carp spawning hotspots within the system Utilise operational strategies to disadvantage Carp spawning/recruitment while maintaining/enhancing the habitat/hydrological conditions for native fish: reduce frequency of managed inundations (1 in 10 years rather than 1 in 2 or 1 in 4) to reduce opportunities for Carp spawning and recruitment take advantage of any natural flooding at the river reach scale to flood Chowilla, to optimise benefits for native fish species considered at risk for a managed inundation, operate the Chowilla environmental regulator to prioritise winter inundation plan for managed recessions before water temperature reaches ~15oC adopt a managed operating regime that maximises flowing water habitat et al. 2011). Physical interventions are not recommended until baseline knowledge gaps regarding basic Carp biology are filled. If future monitoring indicates physical control is applicable, then it is recommended to exclusion techniques, desiccation, and tracking Judas Carp to determine exploitable behaviours. The application of any physical control techniques should be applied in a monitored adaptive management framework.
Stuart (2009) Yatco Lagoon, Murray River, South Australia (~346 ha over two lagoons) N/A (see considerations’) Discusses physical control methods (e.g. screens, wetting/drying, traps) Hydrological scenarios were only related to fish passage and management of Carp screens in low and medium flows; removal of Carp screens when high flow events occur was also suggested Conceptual model of Carp life history in Yatco potential control strategies for each of the species’ life stages Potential risks and benefits for native flora and fauna emphasis on Carp control rather than total eradication. Two key recommendations: minimise the number of and subadult Carp entering and exiting the wetland system minimise the damage to wetland values by adult Carp. Three main strategies were implemented to achieve these recommendations: screens to exclude adult and subadult Carp (<250 mm TL) in low to moderate flows; removal of screens in periods of high flow introduction of wetting and drying schemes harvesting of Carp aggregations at regulators using William’s Carp separation cage.
Stuart et al. (2010) Murrumbidgee Demonstration Reach (UMDR) Bredbo, NSW to Casuarina Sands, ACT (~100 km) N/A (see ‘Other considerations’) Discusses physical control methods (e.g. screens, traps, electrofishing, Judas Carp, netting, recreational fish-outs, chemical poisoning, wetting/drying, aquatic restoration, introduction of diseases and (e.g. daughterless Carp) techniques) Hydrological scenarios were only described as low to moderate maintained throughout the year, with floods occurring occasionally at varying magnitudes Conceptual model of Carp life history in the potential control strategies for each of the species’ life stages Potential risks and benefits for native flora and fauna The overall aim is to rejuvenate native fish communities and aquatic vegetation via the targeted reduction of Carp. More specifically: promote community awareness investigate the effectiveness of various control techniques (e.g. Carp separation cages on regulators) record targeted and sustained reduction of Carp abundance via monitoring and evaluation programs limit Carp recruitment without negatively impacting native fish recruitment gain a better understanding of Carp movements and population dynamics via tracking and evaluation programs.
Stuart (2012) system (~500 1000 square kilometres between the Murray and Edward rivers) N/A Carp management in the Edward–Wakool region is: operational (e.g. flow management) and/or intervention-based (e.g. Williams’ Carp separation cages on fishways and regulators). The three major objectives are to: minimise opportunities for spring/summer floodplain spawning by adult Carp (intervention/ operational) maximise flowing water habitats, which are preferred by native fish (operational), and minimise damage by Carp on riverine/wetland values (intervention/ operational). Potential risks and benefits for native flora and fauna Conceptual model of Carp life history in the system Identification of key knowledge gaps associated with Carp management specifically for the Edward–Wakool area (e.g. identifying Carp spawning habitats and timing/location of Carp aggregations) Operational control methods recommended: bio-manipulation (recovery of native predatory fish via the synchronisation of flow spikes in known spawning periods) reduce frequency of blackwater events rate of recession (floodplain draining of Carp breeding areas to expose and kill eggs) rate of recession (draining of wetlands and floodplains to strand and kill Carp). Intervention control methods recommended: electrofishing removal cage trapping in regulators Judas Carp tracking programs netting key Carp habitats and aggregations (commercial fishing techniques) screens on wetlands exclusion barriers (e.g. sonic and electrical barriers, bubble curtains) chemical poisoning (e.g. rotenone) diseases molecular and biological control (e.g. ‘daughterless’ Carp technology, lethal sterile offspring).
Braysher et al. (2008) Tahbilk Lagoon, Victoria (162 ha) N/A Discusses some physical control techniques and promotes an integrated approach to Carp control Recommends the use of flow to benefit native catfish and is suggestive of how flows can be delivered to disadvantage Carp Generalised conceptual model of Carp life history, including potential control strategies for each stage; potential risks and benefits for native flora and fauna Use a mobile Williams’ Carp separation cage to target various migration bottlenecks (i.e. road crossing, structures); institute formal monitoring, reporting, maintenance, and Carp disposal program. Collect baseline data for native fish. Formalise responsibilities for operation. Develop sophisticated flow-control options for restoring flows to the lagoon while limiting Carp recruitment and maximising benefits for native fish ecology. Install Carp vertical screens in flow-control structures. Utilise an adaptive management approach to account for the flexible life history of Carp and demonstrate Carp management approaches to the community. Implement a monitoring and evaluation program that will demonstrate the effects of Carp management. This should include the installation of PIT tag readers and the development of a small multi-agency team to lead restoration initiatives. *DSE (2003b) Lakes Ramsar Site (955 ha in 12 lakes) N/A Considers restriction of Carp entry N/A Recommendation presented as a management objective: investigate the effectiveness of mechanisms for restricting the entry of Carp, while allowing native fish to enter Hattah Lakes via Chalk Creek, with a view to selecting a cost-effective control mechanism.
*DSE Gunbower Forest Ramsar Site (Ramsar site ~19,450 ha, with wetlands covering ~9,855 ha) N/A N/A N/A Recommendations presented as management objectives: prepare and implement priority plant and animal control programs in accordance with the Mid Murray Forest Action Plan and strategies and Action Plans developed by the CMA coordinate pest plant and animal control efforts with adjacent landholders and management agencies. *Riverine Recovery Program: van Uitregt (2014) (DEWNR) Lakes, South Australia (Management area: 1965 ha; wetland area: 287.8 ha) A 5-year wetland wetting and drying plan is presented Considers restriction of Carp and timing of wetting/drying cycles of the wetlands to restrict Carp recruitment, but at the same time promote native fish recruitment Potential risks and benefits for native flora and fauna associated with wetting/drying cycles and the application of the proposed Carp screens Implementation of optimised fish screens with integrated one-way gates (push traps) at each of the inlet/outlet regulators. Wetting and drying cycles over a 5-year period to be implemented in order to restrict Carp recruitment and promote native fish and vegetation recovery.
*Department of Environment, Water and Natural Resources (Berri): Scott and Suitor (2012) Wetland Complex (Pilby Lagoon: 10.8 ha; Pilby Creek: 33 ha; Lock 6 depression: 5 ha) A 5-year wetland wetting and drying plan is presented Considers restriction of Carp entry and timing of wetting/drying cycles of the wetlands to restrict Carp recruitment Potential risks and benefits for native flora and fauna associated with wetting/drying cycles and the application of the proposed Carp screens Maintain or improve the diversity and abundance of native fish and reduce the abundance of introduced fish species via: implementation of a hydrological regime (wetting/drying) that incorporates variable hydrology in order to promote food production, support the establishment and improvement of habitat condition and support recruitment of native fish operate and maintain current Carp screens on the inlet structure that are of the vertical ‘jail bar’ style, whereby allowing large-bodied native species, e.g. Bony Herring (Nematalosa erebi) to enter the wetland, but exclude Carp Implementing a monitoring program to assess the best time of year for wetting/drying cycles of the wetland so as to determine when spawning and recruitment is most predominant. *Riverine Recovery Program (DEWNR 2013) North Caurnamont (~62 ha) A 5-year wetland wetting and drying plan is presented Considers restriction of Carp entry and timing of wetting/drying cycles of the wetlands to restrict Carp recruitment, but at the same time promote native fish recruitment Potential risks and benefits for native flora and fauna associated with wetting/drying cycles and the application of the proposed Carp screens Implementation of optimised fish screens with integrated one-way gates (push traps) at each of the inlet/outlet regulators. Wetting and drying cycles over a 5-year period to be implemented in order to restrict Carp recruitment and promote native fish and vegetation recovery.
Jumping and pushing traps (Stuart et al. 2006; Thwaites et al. 2010) Designed to separate Carp from native species by exploiting the innate jumping and pushing behaviour of Carp. Native species have not been observed displaying these behaviours. Most effective when targeting annual migrations between channels and off-channel habitat. Requires and infrastructure to mechanically lift and empty captured fish, hence, expensive and
permanent water H8 Wetland Ephemeral, e.g. Hattah Lakes Off-stream wetlands, high elevation wetlands dry out if not reconnected H9 Wetland permanently connected, e.g. adjacent weir pool Wetlands now inundated permanently because of the weir follow weir pool dynamics, e.g. all unregulated weir pool wetlands in Lower Murray H10 Natural floodplain inundation Broad floodplain inundation (as per high-level natural flood) H11 Artificial floodplain inundation, e.g. Chowilla Inundated by regulators H12 e.g. Lake Victoria Lakes Victoria, Cargelligo; permanent water bodies H13 Lakes (terminal), e.g. Alexandrina Permanent water bodies at the end of the system H14 Irrigation channels High flow in irrigation season, then mostly dry/residual pools