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Distribution expansion of the invasive northern snakehead in the United States

This article discusses the distribution and expansion of the invasive northern snakehead (Channa argus) in the United States. It covers the biology of the snakehead, methods of introduction, control methods, research findings, and recommendations for control and monitoring. The article also mentions the potential impact of snakeheads on other species and the efforts to eradicate them in specific regions.

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Distribution expansion of the invasive northern snakehead in the United States

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  1. Distribution expansion of the invasive northern snakehead in the United States By: Josh Newhard Steve Minkkinen Ian Park U.S. Fish and Wildlife Service Maryland Fishery Resources Office

  2. Biology of northern snakehead (Channaargus) • Maximum Length- 1 meter • Typically found in temperate waters • Can tolerate cold water during winter • Mature at 2 years • Reproduce in late spring/early summer • May spawn multiple times per year

  3. Biology • Aggressive nest guarders • Can breathe atmospheric oxygen Image by VDGIF

  4. History • Native to Asia • Methods of introduction: • Common in aquarium trade • Live-fish food market

  5. Introduction to U.S. • FL canals in 2000 • Pond in Crofton, MD in 2002 • Potomac River in 2004 • Arkansas 2008 • Pennsylvania 2008 • New York 2008

  6. Control Methods • Rotenone • Non-specific piscicide • Removal • Capture and kill • Efficient?

  7. Potomac Introduction/Expansion 2004 2006

  8. Expansion in Potomac 2008 2010 N. Snakehead caught in Nanticoke Tributary

  9. Current Potomac Research • Goals to better understand snakehead movements and population size • Creel Surveys • Cooperative Tagging Program • Radio Tagging

  10. Creel Surveys 2008 Creel Survey 2009 Creel Survey Carried out by VDGIF & USFWS CPUE: Largemouth bass: 0.98/hr Northern snakehead: 0.0057/hr = 1 NSH/175 hrs • Done by Virginia Dept. of Game and Inland Fisheries (VDGIF) • CPUE: • Largemouth Bass:1.03 /hr • Northern snakehead: 0.0025/hr = 1 NSH/400 hrs

  11. Cooperative Tagging Program • Partnership with state agencies • VA • MD • DC • First tagging began in Spring 2009 • Rely on agency & angler recaptures

  12. Cooperative Tagging Program • 881 Tagged, 85 Recaptures (~9.6%) • Longest time at large- 387 days • Fish had moved downstream 28 river km • 90% of recaptures in same creek as initial capture • Farthest “migration” was 46.3 river km upstream from initial capture

  13. 2010 Radio Tagging • 12 mature snakeheads implanted with radio tags 0 20mm

  14. 2010 Radio Tagging

  15. Summary/Future Directions • Distribution within Potomac is expanding • Expansion outside of Potomac? • Continued analysis of mark-recapture data for population estimates • Monitor radio tagged fish for one more year • Working with MDDNR to monitor possible impacts on largemouth bass by northern snakehead

  16. Recommendations for control • Creel surveys every 2-3 years • Excellent way to monitor recreational catch rates • Targeted removal during peak capture times • During spring, pre-spawn period and during winter • Continued angler education • Helps in preventing further spread to other waterways

  17. Questions?

  18. 2009 Creel Survey • 264 interviews • 83% of anglers interviewed targeted largemouth bass

  19. 2009 Creel Survey Do you think northern snakehead will impact… Opinions toward targeting snakeheads…

  20. Arkansas • April 2008 • Spawning populations of NSH in Piney Creek • Confined in Piney Creek watershed • Tributary to Big Creek, White River, Mississippi River • Awaiting Commission approval and looking for funding to eradicate NSH in Piney Creek

  21. Pennsylvania • First discovered in ponds at FDR Park in South Philadelphia • NSH found in tidal portion of Schuylkill River near Philadelphia • Angler confirmed capture, 8.3 miles upstream of Delaware River • Tributary to Delaware River

  22. New York • May 2008 • Three NSH captured • Catlin Creek, Ridgebury Lake • Tributary to Hudson River • Proposing to Rotenone

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