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Invasive Fish in the MurrayDarling Basin Symposium on Genetic Biocontrol of Invasive Fish, 21-24 June 2010 Contents • Background • The Murray-Darling Basin Native Fish Strategy • Invasive Fish Species in the MDB • Control of Invasives in the MDB • A Basin Invasive Fish Plan • Conclusions The Murray-Darling Basin •>1 million km2 • 1/7 of Australia • Covers 5 States and Territories • > 2M people • > 40% Australia’s agriculture • Currently worst drought in recorded history Dire Straits • Native fish suffered – both in terms of distribution and abundance – due to human impacts and declining river health • Expert panel concludes - native fish abundance and diversity now at a level of 10% of their status 200+ years ago • Approximately half of the native fish are recognised under conservation concern Native Fish in the MDB • 35 species • 16 are threatened Critically Endangered – Trout Cod Endangered – Barred galaxias Vulnerable – Murray Cod Native Fish Strategy • 50 year plan approved in 2003 • Aim is to restore populations to 60% of preEuropean settlement levels • Addresses 10 key threats to native spp • These include habitat loss, lack of fish passage, extraction, poor water quality, overfishing, and invasive fish. Invasive Fish in the MDB • Atlantic salmon • Brook char • Brown trout* • Carp* • Eastern gambusia* • Goldfish • Oriental weatherloach • Rainbow trout* • Redfin perch • Roach • Tench * = IUCN list of world’s worst invasive species Invasive Fish in the MDB Invasive Fish in the MDB Impacts • • • • • • • Predation (eg Brown trout, Redfin) Competition (eg Carp) Disease (eg Redfin) Injury and stress (eg Gambusia) Damage to infrastructure (eg Carp) Turbidity, undermining banks Unknown, benign, or sleepers (eg tench, roach) Next Invader? The next invasive -Tilapia • Also on IUCN list of world’s worst invasive species • Established and abundant in catchments adjacent to northern MDB • Sought after recreational fish • Projects underway – investigate likely impact; mitigate risk Control - Biological “Daughterless” technology A genetic construct using species-native genes that is inheritable and that biases off-spring sex ratios towards males HindIII mArom EcoRI pBITaB 8400 bp tTA SV40pA BamHI Bglo-pA eGFP HindIII EcoRI TRE PstI CMVmin2 Hinge m/zAr-cDNA m/zAr-cDNA CMVmin 1 Control - Biological Koi herpesvirus Skin necrosis Control - Pheromones Control - Physical • Carp separation cages • Exclusion screens at wetlands • Impact of removal of invasive fish • Fishing Carp separation cage Carp separation cage Carp disposal - Sea to Hume P P P F P F P F F F Key F = fishway P = PIT-tag reader F • Carp at Lock 1 video goes here Carp jumping Carp screen Commercial removal of carp at fishways • Commercial Carp separation facility at new fishway at Lock 1 • 100 tonnes of Carp removed in 2007, 2008, 2009 seasons (October – December) • Part of a “whole of river” solution to disposal of Carp at fishways Carp Exclusion Screens Carp exclusion screens Impact of alien spp removal Impact of alien invasive removal Gambusia Gambusia aggression • Gambusia and golden perch (used in experiments). Hypothetical e.g. of integrated pest management IPM Achieve y % target through cumulative effects Adaptive management: refine targets Population decline To ↓ damage by x % need to ↓ population by y % y% TARGET SMEC QLD SMEC Brenda Park Wetlands Plot types: fully-fenced (top), semi-fenced (middle), unfenced (bottom). An Open water location showing vegetation cover in the fully fenced plot (bottom) versus a semi-fenced plot (top). Regional carp plans Condamine Katarapko Tahbilk Katarapko Condamine Tahbilk Some other projects • A rapid response manual • Review of biocides • Identification of carp hotspots Basin Alien Fish Plan • • • • Focus on prevention Rapid response capacity Manage existing problems Target communications & engagement & capacity building • Due for completion in 2011 Conclusions • NFS supports an integrated approach to invasive spp management • In turn, invasive spp mgt forms part of a holistic approach to river rehabilitation • A large investment, and particular interest in, daughterless carp, pheromones, and other potential biological controls Questions? Integrated pest management 1. Apply a range of carp control techniques, as an integrated package, to intensively reduce carp at a particular location (e.g. a “hotspot”), and measure the response. 2. Demonstrate to the community the commitment to address the carp problem at an on-ground, pragmatic level. ‘Open Water’ Plot ‘Edge’ Plot Carp cage and Lifting Gantry fitted to Inlet Culvert