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 Lakescaused 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 2001Tactile searches for 4 person hours per 50 x 50 m plotCollected 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 >35 cm

Catch per unit effort 0.4 (0.2)a 0.8 (0.37)

a 12.7 (3.44)b

Species Richness 0.5 (0.23)a 0.8 (0.22)

a 3.4 (0.56)b

Number of zebra

mussels per unionid 0

a 0.01 (0.00)

a 3.3 (1.42)b

• Unionids clustered in deep areas (>35 cm) not exposed during late season seiches

• Attached Zebra mussels highest in deep areas

• 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)

Young Marsh (n= 176 mussels)

Pyganodon grandis

Quadrula quadrula

Leptodea fragilis

Toxolasma parvus

Lasmigona complanata

Utterbackia imbecilis

Crane Creek Marsh (n= 1130 mussels) Quadrula quadrula

Leptodea fragilis

Amblema plicata

Pyganodon grandis

Potamilus alatus

Quadrula pustulosa

Toxolasma parvus

*Obliquaria reflexa

Fusconaia flava

Lasmigona complanata

Lampsilis siliquoidea

*Truncilla donaciformis

*Truncilla truncata

*Uniomerus tetralasmus

Utterbackia imbecillis

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

• 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

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

Quadrula - September

0

20

40

60

80

100

Fishless Open Sham

Number ZM/Unionidb

b

a

P<0.001

Leptodea - September

0

20

40

60

80

100

120

Fishless Open Sham

ZM per Unionid

N.S.

Quadrula - July

0

1

2

3

4

5

6

Fishless Open Sham

ZM per Unionid

a

a,b

b

P<0.05

Leptodea - July

0

2

4

6

8

10

Fishless Open Sham

ZM per Unionid

N.S.

Implications

• Predators limit zebra mussels on unionids– Which predators are impacting zebra mussels?

Fish Species Number Size

Bluegill 454 7.4Pumpkinseed Sunfish 152 6.3Green Sunfish 116 4.0Orange-spotted Sunfish 102 7.7Gizzard Shad 60 4.8Black Crappie 54 6.0Brown Bullhead 29 16.9Spottail Shiner 22 3.9Emerald Shiner 19 3.6Common Carp 9 25.7Bowfin 6 56.0White Crappe 6 7.2Tadpole Madtom 4 6.5Brook Silversides 3 5.9Channel Catfish 3 28.0Golden Shiner 3 4.9Largemouth Bass 3 9.9Round Goby 3 3.0Yellow Bullhead 3 4.7Goldfish 2 16.4Black Bullhead 1 5.6Central Mudminnow 1 3.7Freshwater Drum 1 3.9Hybrid Striped Bass 1 15.5Redear 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

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

September - Dead Quadrula

0

20

40

60

80

100

Fishless Sham Carp

ZM per Unionid

a

bb

P<0.05

September - Live Quadrula

0

20

40

60

80

100

Fishless Sham Carp

ZM per Unionid

a

b

b

P<0.01

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

Funded provided by Ohio Department of Natural Resources, Lake Erie Protection Fund, A.&M. Herrick Aquatic Ecology Research Facility Fund

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