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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
• Surveys by Zanatta, Nichols, Schloesser et al. found
remnant unionid populations in some Great Lakes CW and
nearshore areas
Crane Creek Marsh,
Ottawa NWR
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
• Abundant ZM at all locations
• Most in deep areas (>35 cm)
• Collected 1129 unionids in 15 species
• Dominant species: Q. quadrula, P. grandis, L. fragilis, A. plicata
• Aged 1 - 28 years
Water Depth 1
1-17cm
18-35 cm
a
a
Catch per unit effort
0.4 (0.2)
Species Richness
0.5 (0.23)
Number of zebra
a
b
0.8 (0.37)
a
0
>35 cm
12.7 (3.44)
a
0.8 (0.22)
3.4 (0.56)
a
0.01 (0.00)
3.3 (1.42)
mussels per unionid
• Unionids clustered in deep areas (>35 cm) not exposed
during late season seiches
• Attached Zebra mussels highest in deep areas
b
b
• GIS analysis – patchy distribution of unionids
• Most in stream channel, deep pools
• Few in areas dewatered during seiches
• Thick shell species inhabited deepest areas (>35 cm)
• Thin shell species inhabited deep & shallow areas (>15 cm)
Crane Creek Marsh (n= 1130 mussels)
Quadrula quadrula
Leptodea fragilis
Amblema plicata
Pyganodon grandis
Potamilus alatus
Quadrula pustulosa
2001-2008 surveys
similar unionid
communities at
other sites at
Ottawa NWR
Toxolasma parvus
*Obliquaria reflexa
Fusconaia flava
Lasmigona complanata
Lampsilis siliquoidea
*Truncilla donaciformis
*Truncilla truncata
*Uniomerus tetralasmus
Utterbackia imbecillis
Young Marsh (n= 176 mussels)
Gaeth Kurdy Marsh (n= 54 mussels)
Pyganodon grandis
Pyganodon grandis
Quadrula quadrula
Quadrula quadrula
Toxolasma parvus
Potamalis alatus
Utterbackia imbecilis
Leptodea fragilis
Lasmigona complanata
Amblema plicata
Leptodea fragilis
Toxolasma parvus
Lasmigona complanata
Utterbackia imbecilis
• 63% with up to 1/4 of shell covered with byssal threads
• 77% had no live zebra mussels on shell
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)
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
• Added live Quadrula
quadrula, Leptodea fragilis in
June 2007
• Collected in July &
September 2007
• Counted attached zebra
mussels
Quadrula - July
ZM per Unionid
6
Leptodea - July
10
a,b
5
P<0.05
4
b
3
2
1
ZM per Unionid
a
0
Fishless
6
4
2
0
Sham
Fishless
100
120
80
100
b
60
P<0.001
40
20
Open
Sham
Leptodea - September
Quadrula - September
b
0
ZM per Unionid
Number ZM/Unionid
a
Open
N.S.
8
N.S.
80
60
40
20
0
Fishless
Open
Sham
Fishless
Open
• Q. quadrula - Fishless >> Open = Sham
• L. fragilis - N.S.
Sham
Implications
• Predators limit zebra mussels on unionids
– Which predators are impacting zebra mussels?
Fish Species
Number Size
Bluegill
454
7.4
Pumpkinseed Sunfish
152
6.3
Green Sunfish
116
4.0
Orange-spotted Sunfish
102
7.7
Gizzard Shad
60
4.8
Black Crappie
54
6.0
Brown Bullhead
29
16.9
Spottail Shiner
22
3.9
Emerald Shiner
19
3.6
Common Carp
9
25.7
Bowfin
6
56.0
White Crappe
6
7.2
Tadpole Madtom
4
6.5
Brook Silversides
3
5.9
Channel Catfish
3
28.0
Golden Shiner
3
4.9
Largemouth Bass
3
9.9
Round Goby
3
3.0
Yellow Bullhead
3
4.7
Goldfish
2
16.4
Black Bullhead
1
5.6
Central Mudminnow
1
3.7
Freshwater Drum
1
3.9
Hybrid Striped Bass
1
15.5
Redear Sunfish
1
5.6
1058
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
September - Dead Quadrula
September - Live Quadrula
100
a
80
P<0.01
60
b
40
b
20
a
P<0.05
80
ZM per Unionid
ZM per Unionid
100
60
40
b
b
Sham
Carp
20
0
0
Fishless
Sham
Carp
Fishless
• Live Q. quadrula - Fishless >> Sham = Carp
• Dead Q. quadrula - Fishless >> Sham = Carp
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
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