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Mortality of waterbirds in the Upper Mississippi River. Jennifer Sauer; USGS — La Crosse, Wisconsin Dr. Rebecca Cole; USGS—Madison, Wisconsin Dr. Greg Sandland, UW-La Crosse Dr. Roger Haro, UW-La Crosse Jim Nissen; USFWS La Crosse District Ed Britton; USFWS Savanna District.
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Mortality of waterbirds in the Upper Mississippi River Jennifer Sauer; USGS—La Crosse, Wisconsin Dr. Rebecca Cole; USGS—Madison, Wisconsin Dr. Greg Sandland, UW-La Crosse Dr. Roger Haro, UW-La Crosse Jim Nissen; USFWS La Crosse District Ed Britton; USFWS Savanna District Upper Midwest Environmental Sciences Center
Mortality Events 2007 1998 2006-8 1996-P 1992 2002-P 2001-4
Cyathocotyle bushiensis (Coots) Sphaeridiotrema globulus (Scaup, Coots) Leyogonimus polyoon (Coots)
Sphaeridiotrema reside in the small intestine feed on blood, causing severe blood loss and anemia Cyathocotyle reside in the ceca cause a disruption in water and electrolyte balance Leyogonimus polyoon infects primarily the upper and middle areas of the small intestine. severe enteritis characterized by thickening of the intestinal wall that blocks the lumen of the intestine Pathology
Total Mortality Estimates Pool 7 Pool 8 Fall 2002 580 - 700 50 - 65 Fall 2003 6,100 - 7,600 Fall 2004 2,100 - 2,600 10-15 Fall 2005 5,300 - 7,000 150 - 200 Fall 2006 3,700 - 5,000 3,700 - 5,000 Fall 2007 2,100 - 2,700 10,500 -13,000 Total (Spring & Fall) 26,840 - 34,140 16,420 - 20,795
Overall prevalence for parasites at all sites across entire season was 70.75% Highest prevalence for a parasite was in August 83.1% Lowest prevalence for a parasite was in May 54.1% Prevalence of Infection
2006 & 2007 Management study T2 C 6 areas at 110 feet T1 Artificial Island T2 C C T1 T1 Treatments C = Control T1 = Gravel T2 = Gravel/sand mix T2 3 areas at ~90 feet
Monitoring Infected snails found in every pool sampled
>1000 >100 <1000 6-100 1 – 5 2007 Vegetation and Snail Sampling Pool 8 Pool 13 Pool 8
2008—Pools 7 and 8 study Example of sampling protocol Site 2 Site 1 30 cm 60 cm A A B B X 2 X 2 Cobble assessment N
Snail comparisons between pools Pool 7 Pool 8
R2 = 0.88; P = 0.014 Infection Rates
C. bushiensis S. globulus B. tentaculata L. polyoon Documented exotic infection patterns After this summer, additional hosts identified: C. bushiensis S. globulus Amnicola L. polyoon Campeloma
Experimental exposures Conclusion: Bithynia does not appear to be as susceptible to NATIVE parasite species as native snail species
X Molluscacide; Decrease rip rap (rocks) Harvest submersed vegetation Harass birds?? Cover rip-rap Modify island design Pick up dead birds X X X X Management Strategies