1. US Army Corps of Engineers BUILDING STRONG ® The Effects of Suspended Sediment from Western Lake Erie on Walleye (Sander vitreus) Eggs and Fingerlings? Burton Suedel, C.H. Lutz, J.U. Clarke, D.G. Clarke USACE-ERDC-EL, Vicksburg, MS C. Godard-Codding and J. Maul The Institute of Environmental and Human Health Texas Tech University Lubbock, TX Dredging 2012 San Diego, CA 24 October 2012

2. BUILDING STRONG ® 2 Sediment Resuspension The most frequently cited concern related to restrictions imposed on dredging schedules Exposures may affect:  Spawning or foraging behavior  Egg hatching success and larval development  Disrupt anadromous fish migrations  Physical disturbance of habitat by increased sedimentation rates Engbretson Underwater Photography

3. BUILDING STRONG ® Setting Environmental Windows is Controversial  EW: Time periods that allow dredging  No consistent, broadly accepted methodology for objectively setting EWs has emerged  Often set without scientific basis  Established by negotiations emphasizing conservative professional judgments  Lack of effects data for suspended sediments on species used to set EW 3

4. BUILDING STRONG ® Maumee Bay Study Area Spawning Area Larval Nursery Area 4

5. BUILDING STRONG ® Near-field Plume Conditions Maumee Bay Study Area 46 m30 m 15 m LWC Max. Turb. 700 NTU (15 m) < 300 NTU (30m) Max. TSS 800 mg/l Plume Width 50 m Distance from Dredge: 3m Entrained Air UWC Max. Turb. 175 NTU (15 m) 50 NTU (30m) Ambient in < 50 m 5

6. BUILDING STRONG ® Materials and Methods  Flow-through Fish Larvae and Egg Exposure System (FLEES)  3 modules/3 500 L water baths/15 aquaria  Aquaria (15) constructed from 20 L polyethylene carboys  Pump recirculated water and suspended sediment in aquaria  Sediment mixed with water and stored in 375 L tank via double diaphragm pump  Slurry routed through FLEES and reused  Sediment concentrations monitored using OBS 6

7. BUILDING STRONG ® Materials and Methods  Walleye (Sander vitreus)  Four experiments: northern and southern strain eggs (newly spawned) and fingerlings (45-60 d old)  Sediment: Maumee Bay, Ohio (Lake Erie)  Concentrations: 0, 100, 250, 500 mg/L TSS  Duration: 3 days (72 h)  Temp: 10-13°C eggs; 14-17°C fingerlings  PVC cups for containment 7

8. BUILDING STRONG ® Experiments and Endpoints  Two Phases ► 2010 ► 2011  Northern and Southern Strains ► Fingerlings – survival, coiling, scoliosis, lordosis/kyphosis, gill integrity ► Eggs – viability and hatchability, wet and dry mass 8

9. BUILDING STRONG ® 2010 No. Viable Northern Strain Eggs No significant differences among treatments were observed for viable eggs (Anova, F=0.38, P=0.7678). 9

10. BUILDING STRONG ® 2010 No. Viable Southern Strain Eggs No significant differences among treatments were observed for viable eggs (Anova, F=3.53, P=0.0681). 10

11. BUILDING STRONG ® Southern Strain Fingerling Survival Fingerling survival did not differ significantly among TSS treatments (Anova, F=2.74, P=0.113). 11

12. BUILDING STRONG ® Northern Strain Fingerling Gill Lamellae Fingerling gill lamellae did not differ significantly among TSS treatments. 12

13. BUILDING STRONG ® Percent Hatch of Northern Strain Eggs No significant differences among treatments were observed for percent hatch (Anova, F=1.15, P=0.386). 13

14. BUILDING STRONG ® Number of Viable Northern Strain Eggs No significant differences among treatments were observed for viable eggs (Anova, F=0.56, P=0.6533). 14

15. BUILDING STRONG ® Wet Mass Northern Strain Eggs No significant differences among treatments were observed for viable eggs. 15

16. BUILDING STRONG ®  These experimental data can be used with dredge plume characterization data that were obtained for bucket dredging in Maumee Bay to assess potential risk to walleye.  Current EW restrictions in Lake Erie may merit review in light of reduced uncertainty regarding risk associated with effect thresholds within the range of dredging- induced perturbations. Implications 16