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Unionid research in Lake Erie coastal wetlands

Unionid research in Lake Erie coastal wetlands Ferenc A. de Szalay, Richard Bowers, and Doug Kapusinski Department of Biological Sciences. http://el.erdc.usace.army.mil. http://el.erdc.usace.army.mil. Since 1980s, Zebra mussels invaded lower Great Lakes caused drastic declines of unionids

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Unionid research in Lake Erie coastal wetlands

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  1. Unionid research in Lake Erie coastal wetlands Ferenc A. de Szalay, Richard Bowers, and Doug Kapusinski Department of Biological Sciences http://el.erdc.usace.army.mil

  2. http://el.erdc.usace.army.mil • Since 1980s, Zebra mussels invaded lower Great Lakes • caused drastic declines of unionids • Surveys by Zanatta, Nichols, Schloesser et al. found remnant unionid populations in some Great Lakes CW and nearshore areas

  3. Crane Creek Marsh, Ottawa NWR

  4. Crane Creek Marsh, Ottawa NWR Sampled 77 random locations in 2001 Tactile searches for 4 person hours per 50 x 50 m plot Collected zebra mussels on PVC plates at 4 locations

  5. Abundant ZM at all locations • Most in deep areas (>35 cm)

  6. Collected 1129 unionids in 15 species • Dominant species: Q. quadrula, P. grandis, L. fragilis, A. plicata • Aged 1 - 28 years

  7. Unionids clustered in deep areas (>35 cm) not exposed during late season seiches • Attached Zebra mussels highest in deep areas

  8. GIS analysis – patchy distribution of unionids • Most in stream channel, deep pools • Few in areas dewatered during seiches

  9. Thick shell species inhabited deepest areas (>35 cm) • Thin shell species inhabited deep & shallow areas (>15 cm)

  10. 2001-2008 surveys similar unionid communities at other sites at Ottawa NWR

  11. 63% with up to 1/4 of shell covered with byssal threads • 77% had no live zebra mussels on shell

  12. Why are unionids surviving in Crane Creek Marsh? • Zebra mussel mortality when unionids burrow in sediments (e.g. Nichols and Wilcox 1997) • Predation of zebra mussels by fish and waterfowl (e.g., Petrie and Knapton 1999, Magoulick and Lewis 2002)

  13. Predator Exclosure Experiment • 5-m diameter Exclosures with: • 3 X 3 cm mesh sides - Fishless • 3 X 3 cm mesh sides with 1 m X 1 m holes - Open • Stakes only - Sham

  14. Added live Quadrula quadrula, Leptodea fragilis in June 2007 • Collected in July & September 2007 • Counted attached zebra mussels

  15. Q. quadrula - Fishless >> Open = Sham • L. fragilis - N.S.

  16. Implications • Predators limit zebra mussels on unionids • Which predators are impacting zebra mussels?

  17. Carp Enclosure Experiment • 5-m diameter Exclosures with: • 3 X 3 cm mesh sides - Fishless • Stakes only - Sham • 3 X 3 cm mesh sides with 1 carp - Carp • Added live and dead Q. quadrula in June 2008 • Collected live and dead Q. quadrula in July, Sept. 2008 • Counted attached zebra mussels

  18. Live Q. quadrula - Fishless >> Sham = Carp • Dead Q. quadrula - Fishless >> Sham = Carp

  19. Conclusions • Zebra mussel survive in Great Lakes coastal marshes • Zebra mussel reduced by fish predation • Common Carp are key predators of zebra mussel on unionids • Unionid burrowing during summer does not eliminate attached zebra mussels

  20. Thanks to: Dan Frisk, Doug Brewer, Ron Huffman, USFWS; Chris Dwyer, Ohio DNR Field and laboratory help by D. Kapusinski, J. Clark, N. Yaussy, J. Bowers, A. Brager. M. Rubin, K. Gee, Robert Christy, KSU photgrapher Funded provided by Ohio Department of Natural Resources, Lake Erie Protection Fund, A.&M. Herrick Aquatic Ecology Research Facility Fund

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