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Invasive Northern Pike Suppression Pend Oreille River, WA

Invasive Northern Pike Suppression Pend Oreille River, WA. Presented By Nick Bean. Location. Cusick/Gardiner Slough. Campbell Slough. Background. Northern pike established prior to 2004 Began monitoring/investigating the population in 2005

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Invasive Northern Pike Suppression Pend Oreille River, WA

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  1. Invasive Northern Pike Suppression Pend Oreille River, WA Presented By Nick Bean

  2. Location • Cusick/Gardiner Slough • Campbell Slough

  3. Background • Northern pike established prior to 2004 • Began monitoring/investigating the population in 2005 • Exponential increase from ~400 in 2006 to >5,500 in 2010 • Range expanded throughout reservoir as well as downstream • Boundary Reservoir and Upper Columbia River • Most other species except smallmouth bass and tench have declined significantly

  4. Threats of Expanding Population • Local • Native species conservation and recovery in lower Pend Oreille • Box Canyon, Boundary dams FERC license implementation • Further illegal introductions into neighboring waters • Columbia River • ESA recovery • Tribal, recreational, commercial salmon and steelhead fisheries • Lake Roosevelt resident fish mitigation and substitution

  5. Management Objectives • Reduce abundance (CPUE) of NP in BCR from 2011’s 13.2 NP/net night to <1.73 NP/net night in southern ½ of reservoir and <0.5 NP/net night in northern ½ in SPIN survey by 2014 (87% reduction) • Back-calculated from population estimates and gill net CPUE assuming 1:1 relationship

  6. Three-Pronged Approach • Increase angler exploitation through education and outreach • Promote fishing contests that provide incentive for harvest • PikePalooza 2012 ($10,000) • PikePalooza 2013 ($5,000) • PikePalooza 2014 ($5,000) • Mechanical Suppression • Intensive gill netting (3 years minimum) • Up to 32 nets per day

  7. Mechanical Suppression • Phase I (March-Late April/Early May) • Gillnet spawning locations in southern ½ of reservoir • SPIN (Late April/Early May) • Target < 1.73 NP/night in southern ½ of reservoir • Target < 0.5 NP /night in northern ½ of reservoir • Phase II (Post SPIN-Mid June) • Gillnet until 87% reduction in daily catch at each location • Target higher concentrations based on SPIN results

  8. 2012 Suppression Results • 1,031 gillnets set (29.29 miles):Phase I = 524; Phase II = 507 • 5,808 NP removed: PI = 4,552; PII = 1,256(CPUE = 5.6NP/Net) • Mean TL = 537 mm (21.1 in), 1,285 g (2.8 lbs) • 48.65% Female (48.20% F. mature; 68.86% M. mature) • Bycatch: 20 fish species, 17,460 individuals, ~90 % survival

  9. Suppression Adaptations for 2013 • Objectives • Avoid higher reservoir elevations/macrophyte development • Target more pre-spawn NP • Hit target reduction prior to SPIN so Phase II is unnecessary • Reduce bycatch and increase survival • Reduce angler interaction/interference • How • 3/19/2013 start date vs. 3/5/2012 start date • Up to 32 nets/day (2013) vs. up to 19 nets/day (2012) • No weekends in 2013

  10. 2013 Suppression Results • 1,217gillnets set (34.5 miles): Phase I= 1,027; Phase II = 190 • 6,452 NP removed: PI= 5,953; PII = 499 (CPUE = 5.30 NP/Net) • Mean TL = 440 mm (17.3 in), 670 g (1.5 lbs) • 48.95% Female (17.74% F. mature; 66.83% M. mature) • Bycatch: 21 fish species, 12,216 individuals, ~90 % survival

  11. Suppression Comparison: 2012 vs. 2013 • Effort and total NP removed • 1,031 (2012) vs. 1,217 (2013) gillnets set • 5,808 (2012) vs. 6,452 (2013) NP removed • 8.4 mT (2012) vs. 4.3 mT (2013) NP removed • 15% (2012) vs. 60.33% (2013) NP <450 mm • Objectives for 2013 • Reduced bycatch: 17,460 (2012) vs. 10,513 (2013) • Targeted pre-spawn NP: 15.3% (2012) vs. 5.5% (2013) S.O. NP • Reduced interaction/interference with anglers • Hit target reduction so Phase II would be unnecessary • Met in Southern half but not in Northern half • Minimalized Phase II effort

  12. Suppression Comparison: 2012 vs. 2013

  13. Suppression Comparison: 2012 vs. 2013 2012 2013

  14. Next Steps: Monitoring & Implementation • SPIN (Annually), expand to Boundary? • Reservoir-wide warmwater survey (2014) • Mechanical suppression at current level through 2014 • Investigate suppression measures beyond 2014 • Explore other control measures or modify existing ones • Report to ISRP (2014) • 2014 PikePalooza Derby • http://wdfw.wa.gov/ais/esox_lucius/

  15. Acknowledgements • Bonneville Power Administration • US Bureau of Indian Affairs • Avista Corporation • Seattle City Light • Eastern Washington University • Washington Department of Fish and Wildlife • Kalispel Tribe of Indians • Hardworking KNRD Field Crew

  16. Question? Comments?

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